5-Aminolevulinic acid(ALA),is a novel plant growth regulator that can enhance plant tolerance against salt stress.However,the molecular mechanism of ALA is not well studied.In this study,ALA improved salt tolerance of...5-Aminolevulinic acid(ALA),is a novel plant growth regulator that can enhance plant tolerance against salt stress.However,the molecular mechanism of ALA is not well studied.In this study,ALA improved salt tolerance of apple(Malus×domestica'Gala')when the detached leaves or cultured calli were used as the materials.The expression of MdWRKY71,a WRKY transcription factor(TF)gene was found to be responsive to NaCl as well as ALA treatment.Functional analysis showed that overexpressing(OE)-MdWRKY71 significantly improved the salt tolerance of the transgenic apple,while RNA interfering(RNAi)-MdWRKY71 reduced the salt tolerance.However,exogenous ALA alleviated the salt damage in the RNAi-MdWRKY71 apple.When MdWRKY71 was transferred into tobacco,the salt tolerance of transgenic plants was enhanced,which was further improved by exogenous ALA.Subsequently,MdWRKY71 bound to the W-box of promoters of MdSOS2,MdNHX1,MdCLC-g,MdSOD1,MdCAT1 and MdAPX1,transcriptionally activating the gene expressions.Since the genes are responsible for Na+and Cl-transport and antioxidant enzyme activity respectively,it can be concluded that MdWRKY71,a new TF,is involved in ALA-improved salt tolerance by regulating ion homeostasis and redox homeostasis.These results provided new insights into the transcriptional regulatory mechanism of ALA in enhancing apple salt tolerance.展开更多
The content of soluble sugars is a vital parameter that indicates the quality of fleshy fruits such as apple(Malus domestica Borkh.).Studying the patterns of accumulation of soluble sugars and regulatory mechanisms as...The content of soluble sugars is a vital parameter that indicates the quality of fleshy fruits such as apple(Malus domestica Borkh.).Studying the patterns of accumulation of soluble sugars and regulatory mechanisms associated with fruit development is crucial for breeding improved fruit varieties.Here,we report that MdCIbHLH1,a low temperature-induced b HLH transcription factor,inhibits the accumulation of soluble sugars by regulating sugar-metabolizing enzyme activities,photosynthetic performance,and the expression of sugar-related genes in developing apple fruits.MdCIbHLH1 inhibits MdFBP and MdPEPCK expression,thus blocking the conversion of acids to sugars in apple fruits.We also discovered that MdCIbHLH1 decreases the photosynthetic rate and carbohydrate accumulation in apple leaves.Our results suggest that soluble sugar accumulation in apple fruits is influenced by multiple factors,including metabolic status,photosynthesis,and carbohydrate allocation.MdCIbHLH1 is critically involved in controlling the accumulation of soluble sugars by coordinating carbohydrate synthesis and allocation,thus influencing sugar transport and its metabolism during the development of apple fruits.展开更多
Cadmium(Cd)stress is a serious threat to apple growth and development.Ethylene response factors(ERFs)are a major family of transcription factors(TFs)that play a key role in the resistance to Cd stress.In this study,we...Cadmium(Cd)stress is a serious threat to apple growth and development.Ethylene response factors(ERFs)are a major family of transcription factors(TFs)that play a key role in the resistance to Cd stress.In this study,we found that the ERF TF Md ERF114 was induced in response to Cd stress.The overexpression of Md ERF114 in apple(Malus domestica)roots reduced the accumulation of Cd in the plants and enhanced their tolerance to Cd stress.Yeast one-hybrid(Y1H)assays,dual-luciferase assays,and electrophoretic mobility shift assays indicated that MdERF114 directly binds to the promoter of MdATG16 and activates its expression to increase autophagic activity,which leads to higher resistance to Cd stress.In addition,MdMYB306 interacts with MdERF114 and enhances the resistance to Cd stress by promoting the binding of MdERF114 to the promoter of MdATG16.Our findings reveal an important mechanism by which MdMYB306-MdERF114-MdATG16 influences the resistance of apple to Cd stress.展开更多
5-Aminolevulinic acid(ALA)is a novel plant growth regulator that has shown outstanding capability to promote stomatal opening.Starch degradation,catalyzed byβ-amylase(EC3.2.1.2,BAM),plays an important role in stomata...5-Aminolevulinic acid(ALA)is a novel plant growth regulator that has shown outstanding capability to promote stomatal opening.Starch degradation,catalyzed byβ-amylase(EC3.2.1.2,BAM),plays an important role in stomatal opening.However,whether the starch breakdown is involved in ALA-regulating stomatal movement is unclear.In the current study,we found that exogenous ALA effectively stimulated the starch breakdown in guard cells,increasedβ-amylase activity and promoted stomatal opening in leaves of apple(Malus×domestica).Based on genome-wide identification,we identified a total of 119 members of BAM gene family in ten commonly Rosaceae crops.Analyses of gene structure,motif identification,and gene pair collinearity revealed relative conservation among members within the same group or subgroup.Among these genes,MdBAM17 and other 12 genes were identified as the orthologous genes of AtBAM1,which is responsible for starch degradation to modulate the stomatal movement in Arabidopsis.qRT-PCR analysis revealed a positive correlation between the expressions of MdBAM17 and stomatal aperture,as well asβ-amylase activity,whereas a negative correlation was observed with the starch content.Subcellular localization analysis confirmed that MdBAM17 is a chloroplast protein,consistent with the AtBAM1.MdBAM17 was mainly expressed in guard cells and responsive to exogenous ALA.Overexpressing MdBAM17 increasedβ-amylase activity and promoted starch breakdown,leading to stomatal opening,which was further strengthened by ALA.RNA-interfering MdBAM17 decreasedβ-amylase activity,resulting in starch accumulation,and impairing the stomatal opening by ALA.However,modulation of MdBAM17 expression did not affect the levels of flavonols and H_(2)O_(2)in guard cells,suggesting that MdBAM17-promoted starch degradation may function at downstream of ROS signaling in the ALAregulated stomatal opening.Our findings provide new insights into the mechanisms of ALA-regulated stomatal movement.展开更多
Apple replant disease is a complex soil syndrome that occurs when the same fields are repeatedly utilized for apple orchard cultivation.It can be caused by various pathogens,and Fusarium solani is the main pathogen.Fu...Apple replant disease is a complex soil syndrome that occurs when the same fields are repeatedly utilized for apple orchard cultivation.It can be caused by various pathogens,and Fusarium solani is the main pathogen.Fusarium solani disrupts the structure and function of the orchard soil ecosystem and inhibits the growth and development of apple trees,significantly impacting the quality and yield of apples.In this study,we conducted a transcriptome comparison between uninoculated apple saplings and those inoculated with F:solani.The differentially expressed genes were mainly enriched in processes such as response to symbiotic fungus.Plant defensins are antimicrobial peptides,but their roles during F.solani infection remain unclear.We performed a genome-wide identification of apple defensin genes and identified 25 genes with the conserved motif of eight cysteine residues.In wildtype apple rootstock inoculated with F.solani,the root surface cells experienced severe damage,and showed significant differences in the total root length,total root projection area,root tips,root forks,and total root surface area compared to the control group.qRT-PCR analysis revealed that MdDEF3 and MdDEF25 were triggered in response to F.solani infection in apples.Subcellular localization showed specific expression of the MdDEF3-YFP and MdDEF25-YFP proteins on the cell membrane.Overexpressing theMdDEF25-YFP fusiongene enhanced resistance against F.solani in apple,providing a new strategy for the future prevention and biological control of apple replantdisease.展开更多
Cashew processing in Côte d’Ivoire focuses only on the cashew nut, to the detriment of the apple. Only a very small proportion of the apple is processed into juice. The aim of this work is to enhance the value o...Cashew processing in Côte d’Ivoire focuses only on the cashew nut, to the detriment of the apple. Only a very small proportion of the apple is processed into juice. The aim of this work is to enhance the value of cashew apples by transforming them into jam. Specifically, the aim was first to characterize the sensory properties of cashew apple jam formulations using baobab powder as a source of pectin and then to optimise the formulations. A Box-Behken design with pH, Sugar, and Baobab as factors was used to model and characterize the jam sensory descriptors, and a multivariate analysis with SensomineR was used to characterize the jam formulations. The desirability function was used to optimise the formulations. The results show globally significant regressions at the 0.05 threshold for the sensory descriptors Gelling, Brilliance, Smell, Sweetness, and (-)Astringency, with the exception of (-)Salinity. The R2 coefficients are greater than 80%. The factors studied could have effects on the sensory descriptors of cashew jam formulations. The Baobab had the main effect on the gelling, smell, and astringency of the jams. Brilliance depended on the added sugar. A product effect (p < 0.001) was observed for the descriptors Smell, Gelling, Brilliance, and Sweetness, as these allowed the panelists to find differences between the formulations. Optimum jam formulation can be achieved with 51.56% sugar and 2.12% Baobab at a pH of 3.15. Cashew apple jam using Baobab offers opportunities to add value to apples that have long been abandoned in the field. It would be important to find conditions for prolonged storage of this jam.展开更多
Chlorogenic acid(CGA),a potent antioxidant with antimicrobial,antiviral,and metabolic regulatory properties,plays multifunctional roles in apple fruit by enhancing postharvest quality,extending shelf life through oxid...Chlorogenic acid(CGA),a potent antioxidant with antimicrobial,antiviral,and metabolic regulatory properties,plays multifunctional roles in apple fruit by enhancing postharvest quality,extending shelf life through oxidative stress reduction,and inhibiting enzymatic browning to preserve color,flavor,and nutritional integrity.Despite the established role of hydroxycinnamoyl transferase(HCT)as a rate-limiting enzyme in CGA biosynthesis,the specific HCT gene responsible for this process and its regulatory mechanisms remain elusive.To address this knowledge gap,we systematically investigated CGA accumulation dynamics during apple storage and functionally characterized MdHCT6,a candidate gene within the HCT family.We found that the chlorogenic acid content in apple fruit increased significantly during postharvest storage compared with the initial storage.Transcriptome analysis showed that the expression level of MdHCT6 was significantly higher than that of other HCT homologues,which was consistent with the reverse transcription quantitative PCR(RT-qPCR)results.In vitro enzymatic assays demonstrated that MdHCT6 catalyzes the synthesis of chlorogenic acid using shikimic acid and quinic acid as precursors,while genetic evidence confirmed its role as a key positive regulator of chlorogenic acid accumulation in apples.Furthermore,we identified the transcription factor MdMYB93 as a direct upstream activator of MdHCT6,establishing a regulatory cascade that governs CGA production.This work not only deciphers the molecular hierarchy of CGA biosynthesis in apples but also provides actionable targets for genetic improvement of antioxidant capacity and postharvest resilience in apple germplasm.展开更多
Apple polyphenols are widely present in apple pulp,peel,kernel,and leaves.They are natural bioactive substances with a variety of health functions.This review describes the antioxidant functions of anthocyanins,querce...Apple polyphenols are widely present in apple pulp,peel,kernel,and leaves.They are natural bioactive substances with a variety of health functions.This review describes the antioxidant functions of anthocyanins,quercetin,phlorizin,chlorogenic acid,and epicatechin in apple polyphenols through the regulation of signal pathways and transcription factors,and the inhibition or induction of enzymes.Massive food applications of apple polyphenols are summarized,including excellent color protection of fruits and vegetables,meat preservation,preparation of composite packaging fi lms as active ingredients,enhancement of nutritional value as functional ingredients,and improvement of food taste and physical stability.This review would provide a reference for the exploration of apple polyphenol resources and its development in the food field.展开更多
Defensin,an essential component of plant development,is indispensable in pathogen resistance.However,the molecular function of defensins under pathological conditions of Cytospora canker has not been characterized in ...Defensin,an essential component of plant development,is indispensable in pathogen resistance.However,the molecular function of defensins under pathological conditions of Cytospora canker has not been characterized in apple plants.The present study exhibits a detailed overview of the phylogeny and structure of 29 defensins(MdDEF)in apple.Expression analysis revealed that MdDEF genes were spatiotemporally diverse across apple tissues.Five MdDEF genes were found to be significantly up-regulated following a challenge with Cytospora mali.The transgenic overexpression of five defensin genes in apple calli enhanced resistance to C.mali.Among them,MdDEF30 was strongly induced and conferred the highest resistance level in vivo.Meanwhile,antifungal activity assays in vitro demonstrated that a recombinant protein produced from MdDEF30could inhibit the growth of C.mali.Notably,MdDEF30 promoted the accumulation of reactive oxygen species(ROS)and activated defense-related genes such as PR4,PR10,CML13,and MPK3.Co-expression regulatory network analysis showed that MdWRKY75 may regulate the expression of MdDEF30.Further yeast onehybrid(Y1H),luciferase,and chromatin Immunoprecipitation quantitative polymerase chain reaction(ChIPqPCR)assays verified that MdWRKY75 could directly bind to the promoter of MdDEF30.Importantly,pathogen inoculation assays confirmed that MdWRKY75 positively regulates resistance by transcriptionally activating MdDEF30.Overall,these results demonstrated that MdDEF30 promotes resistance to C.mali in apple plants and that MdWRKY75 regulates MdDEF30 expression during the induction of resistance,thereby clarifying biochemical mechanisms of resistance to C.mali in apple trees.展开更多
[Objectives]This study was conducted to investigate the physicochemical and functional properties of soluble dietary fiber(SDF)from apple pomace.[Methods]Soluble dietary fiber(SDF)from apple pomace was extracted by di...[Objectives]This study was conducted to investigate the physicochemical and functional properties of soluble dietary fiber(SDF)from apple pomace.[Methods]Soluble dietary fiber(SDF)from apple pomace was extracted by direct water extraction(W),lactic acid bacteria fermentation(F)and steam explosion(SE)respectively,and the extraction methods and physicochemical and functional characteristics were compared and analyzed.[Results]The solubility,water holding capacities,oil holding capacities and swelling capacities of W-SDF,F-SDF and SE-SDF were(2.13,3.95 and 5.13 g/g),(9.02,13.75 and 15.88 g/g),(2.13,4.08 and 5.11 g/g),and(10.82,14.03 and 15.77 ml/g),respectively.Their emulsifying activity,emulsifying stability and least gelation concentration were(30.28,47.95 and 58.72 ml/100 ml),(37.88,45.25 and 57.13 ml/100 ml),and(12.11,11.25 and 9.87%),respectively.The adsorption capacities of W-SDF,F-SDF and SE-SDF for heavy metals(Pb,As and Cu)in the intestinal environment(pH 7)were(162.7,183.5 and 197.3μmol/g),(132.8,156.7 and 168.9μmol/g),and(57.2,63.5 and 89.2μmol/g)respectively.In the gastric environment(pH 2),they were(72.8,110.5,138.9μmol/g),(82.1,112.5,135.7μmol/g),and(38.9,42.7,55.1μmol/g)respectively.[Conclusions]The study can provide a theoretical basis for functional modification and comprehensive utilization of dietary fiber from apple pomace.展开更多
Ethylene response factors 2(ERF2) are essential for plant growth, fruit ripening, metabolism, and resistance tostress. In this study, the expression levels of the genes for MdERF2 implicated in the biosynthesis, compo...Ethylene response factors 2(ERF2) are essential for plant growth, fruit ripening, metabolism, and resistance tostress. In this study, the expression levels of the genes for MdERF2 implicated in the biosynthesis, compositionand ultrastructure of fruit cuticular wax in apple(Malus domestica) were studied by the transfection of apple fruitand/or calli with MdERF2-overexpression(ERF2-OE) and MdERF2-interference(ERF2-AN) vectors. In addition,the direct target genes of MdERF2 related to wax biosynthesis were identified using electrophoretic mobility shiftassays(EMSAs) and dual-luciferase reporter(DLR) assays. The findings indicated that the expression levels offour wax biosynthetic genes, long-chain acyl-CoA synthetase 2(MdLACS2), eceriferum 1(MdCER1), eceriferum4(MdCER4), and eceriferum 6(MdCER6), were upregulated by ERF2-OE. In contrast, the expression levels ofthese genes were inhibited when MdERF2 was silenced. Furthermore, the overall structure and accumulationof fruit cuticular wax were influenced by the expression level of MdERF2. Treatment with ERF2-OE significantlyincreased the proportions of alkanes and ketones and reduced the proportions of fatty acids and esters. In addition,the EMSAs and DLR assays demonstrated that MdERF2 could bind directly to GCC-box elements in the promotersof MdLACS2, MdCER1, and MdCER6 to activate their transcription. These results confirmed that MdERF2 targetsthe up-regulation of expression of the MdLACS2, MdCER1, and MdCER6 genes, thereby altering the composition,content, and microstructure of apple epidermal wax.展开更多
The cultivation of apples in replanted orchards is essential given limitations in land resources.However,the presence of Fusarium and phenolic acids in the replanted soil harms the soil environment,which impedes the s...The cultivation of apples in replanted orchards is essential given limitations in land resources.However,the presence of Fusarium and phenolic acids in the replanted soil harms the soil environment,which impedes the sustainable development of the apple industry.In this study,earthworm was used as the fermentation precursor protein to optimize the fermentation conditions,and the inhibition mechanism of the fermentation product on Fusarium and its potential to repair the apple replant soil environment were explored.Laboratory experiments showed that the optimum initial pH,temperature and time of earthworm fermentation were 7,37℃ and 10 d,respectively.The inhibition rates of earthworm fermentation products against F.oxysporum,F.solani,F.proliferatum,and F.moniliforme were 79.8%,75.1%,78.7%and 79.2%,respectively.The inhibition rates of spore germination on F.oxysporum,F.solani,F.proliferatum,and F.moniliforme were 83.8%,87.3%,83.2%and84.8%,respectively.In the field,use 300 mL of earthworm fermentation products for each planting pits before planting.The experimental results showed that,compared with the control,the content of soil pathogenic Fusarium and phenolic acid in Wantou(W3)were decreased by75.1%and 59.8%,respectively,after treatment with earthworm fermentation products in 2019.Soil urease,phosphatase,sucrase and catalase activities increased by 383.2%,78.2%,130.3%and 43.5%,respectively.The fruit weight,anthocyanin content,soluble sugar,sugar-acid ratio,total ester ratio,total ester concentration and yield increased by 80.7%,60.6%,25.6%,50.3%,19.7%,262.4%and 193.5%,respectively,while titratable acid content decreased by 16.9%.In conclusion,earthworm fermentation products can be used as a sustainable amendment to control apple replant disease.展开更多
Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of apple.To understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes o...Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of apple.To understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes of two apple cultivars‘Hanfu'(HF)(resistant)and‘Golden Delicious'(GD)(susceptible)were analyzed at 0,6,18,24 and 48 h after AAAP inoculation by RNA-Seq.At each time point,a large number of significantly differentially expressed genes(DEGs)were screened between AAAP-inoculated and uninoculated apple leaves.Analysis of the common DEGs at four time points revealed significant differences in the resistance of‘HF'and‘GD'apple to AAAP infection.RLP,RNL,and JA signal-related genes were upregulated in both cultivars to restrict AAAP development.However,genes encoding CNLs,TNLs,WRKYs,and AP2s were only activated in‘HF'as part of the resistance response,of which,some play major roles in the regulation of ET and SA signal transduction.Further analysis showed that many DEGs with opposite expression trends in the two hosts may play important regulatory roles in response to AAAP infection.Transient expression of one such gene MdERF110 in‘GD'apple leaves improved AAAP resistance.Collectively,this study highlights the reasons for differential resistance to AAAP infection between‘HF'and‘GD'apples which can theoretically assist the molecular breeding of disease-resistant apple crops.展开更多
Abiotic stress reduces plant yield and quality.WRKY transcription factors play key roles in abiotic stress responses in plants,but the molecular mechanisms by which WRKY transcription factors mediate responses to drou...Abiotic stress reduces plant yield and quality.WRKY transcription factors play key roles in abiotic stress responses in plants,but the molecular mechanisms by which WRKY transcription factors mediate responses to drought and osmotic stresses in apple(Malus×domestica Borkh.)remain unclear.Here,we functionally characterized the apple GroupⅢWRKY gene MdWRKY115.qRT-PCR analysis showed that MdWRKY115 expression was up-regulated by drought and osmotic stresses.GUS activity analysis revealed that the promoter activity of MdWRKY115 was enhanced under osmotic stress.Subcellular localization and transactivation assays indicated that MdWRKY115 was localized to the nucleus and had a transcriptional activity domain at the N-terminal region.Transgenic analysis revealed that the overexpression of MdWRKY115 in Arabidopsis plants and in apple callus markedly enhanced their tolerance to drought and osmotic stresses.DNA affinity purification sequencing showed that MdWRKY115 binds to the promoter of the stress-related gene MdRD22.This binding was further verified by an electrophoretic mobility shift assay.Collectively,these findings suggest that MdWRKY115 is an important regulator of osmotic and drought stress tolerance in apple.展开更多
Auxin is throughout the entire life process of plants and is involved in the crosstalk with other hormones,yet its role in apple disease resistance remains unclear.In this study,we investigated the function of auxin/i...Auxin is throughout the entire life process of plants and is involved in the crosstalk with other hormones,yet its role in apple disease resistance remains unclear.In this study,we investigated the function of auxin/indole-3-acetic acid(IAA)gene Md IAA24 overexpression in enhancing apple resistance to Glomerella leaf spot(GLS)caused by Colletotrichum fructicola(Cf).Analysis revealed that,upon Cf infection,35S::Md IAA24 plants exhibited enhanced superoxide dismutase(SOD)and peroxidase(POD)activity,as well as a greater amount of glutathione(reduced form)and ascorbic acid accumulation,resulting in less H_(2)O_(2)and superoxide anion(O_(2)^(-))in apple leaves.Furthermore,35S::Md IAA24 plants produced more protocatechuic acid,proanthocyanidins B1,proanthocyanidins B2 and chlorogenic acid when infected with Cf.Following Cf infection,35S::Md IAA24 plants presented lower levels of IAA and jasmonic acid(JA),but higher levels of salicylic acid(SA),along with the expression of related genes.The overexpression of Md IAA24 was observed to enhance the activity of chitinase andβ-1,3-glucanase in Cfinfected leaves.The results indicated the ability of Md IAA24 to regulate the crosstalk between IAA,JA and SA,and to improve reactive oxygen species(ROS)scavenging and defense-related enzymes activity.This jointly contributed to GLS resistance in apple.展开更多
Accurate diagnosis of apple leaf diseases is crucial for improving the quality of apple production and promoting the development of the apple industry. However, apple leaf diseases do not differ significantly from ima...Accurate diagnosis of apple leaf diseases is crucial for improving the quality of apple production and promoting the development of the apple industry. However, apple leaf diseases do not differ significantly from image texture and structural information. The difficulties in disease feature extraction in complex backgrounds slow the related research progress. To address the problems, this paper proposes an improved multi-scale inverse bottleneck residual network model based on a triplet parallel attention mechanism, which is built upon ResNet-50, while improving and combining the inception module and ResNext inverse bottleneck blocks, to recognize seven types of apple leaf(including six diseases of alternaria leaf spot, brown spot, grey spot, mosaic, rust, scab, and one healthy). First, the 3×3 convolutions in some of the residual modules are replaced by multi-scale residual convolutions, the convolution kernels of different sizes contained in each branch of the multi-scale convolution are applied to extract feature maps of different sizes, and the outputs of these branches are multi-scale fused by summing to enrich the output features of the images. Second, the global layer-wise dynamic coordinated inverse bottleneck structure is used to reduce the network feature loss. The inverse bottleneck structure makes the image information less lossy when transforming from different dimensional feature spaces. The fusion of multi-scale and layer-wise dynamic coordinated inverse bottlenecks makes the model effectively balances computational efficiency and feature representation capability, and more robust with a combination of horizontal and vertical features in the fine identification of apple leaf diseases. Finally, after each improved module, a triplet parallel attention module is integrated with cross-dimensional interactions among channels through rotations and residual transformations, which improves the parallel search efficiency of important features and the recognition rate of the network with relatively small computational costs while the dimensional dependencies are improved. To verify the validity of the model in this paper, we uniformly enhance apple leaf disease images screened from the public data sets of Plant Village, Baidu Flying Paddle, and the Internet. The final processed image count is 14,000. The ablation study, pre-processing comparison, and method comparison are conducted on the processed datasets. The experimental results demonstrate that the proposed method reaches 98.73% accuracy on the adopted datasets, which is 1.82% higher than the classical ResNet-50 model, and 0.29% better than the apple leaf disease datasets before preprocessing. It also achieves competitive results in apple leaf disease identification compared to some state-ofthe-art methods.展开更多
Apple replant disease(ARD) is primarily caused by biotic factors that seriously inhibits the development of apple industry. Therefore, the use of biological control measures to inhibit the main pathogens(such as Fusar...Apple replant disease(ARD) is primarily caused by biotic factors that seriously inhibits the development of apple industry. Therefore, the use of biological control measures to inhibit the main pathogens(such as Fusarium spp.) that cause ARD is of great significance to the sustainable development of the apple industry. Trichoderma virens 6PS-2, which exhibited antagonism toward a variety of pathogens, was screened from the rhizosphere soils of healthy apple trees(Malus robusta) in different replanted orchards in the Yantai and Zibo Cities, Shandong Province, China. Its fermentation extract inhibited the growth of pathogenic Fusarium proliferatum f. sp. Malus domestica MR5, which was proportional to the concentration. These substances also increased the hairy root volume and growth of Arabidopsis thaliana lateral roots. The phenotype of Malus hupehensis seedlings and microbial community structure in rhizosphere soils in greenhouse experiment using Highthroughput sequencing were analyzed, and the field experiment with grafted apple trees were used for further verification. Compared with the application of potato dextrose broth(PDB) medium, application of 6PS-2 spore suspension directly to replanted soils could improve the growth of M. hupehensis seedlings as well as the elongation of grafted apple trees. Concomitant decreases in the gene copy number of Fusarium and increases in the culturable bacteria/fungi were also observed in the greenhouse and field experiments. The abundance of Trichoderma,Bacillus, and Streptomyces increased significantly, but that of Fusarium, Pseudarthrobacter, and Humicola decreased. The content of esters, phenols,furans, and amino acids in root exudates of M. hupehensis seedlings increased, which significantly inhibited the multiplication of Fusarium, but was positively correlated with Bacillus and Trichoderma. In summary, T. virens 6PS-2 not only directly inhibits the activity of pathogenic Fusarium but also secrets secondary metabolites with antifungal and growth-promoting potential. In addition, 6PS-2 spore suspension can also promote the growth of plants to a certain extent, and change the soil microbial community structure of rhizosphere soils. It is believed that T. virens 6PS-2 has the potential for the alleviation of apple replant disease(ARD) in China.展开更多
Apple replant disease(ARD)negatively affects plant growth and reduces yields in replanted orchards.In this study,biochar was applied to apple replant soil with Fusarium oxysporum.Our aim was to investigate whether bio...Apple replant disease(ARD)negatively affects plant growth and reduces yields in replanted orchards.In this study,biochar was applied to apple replant soil with Fusarium oxysporum.Our aim was to investigate whether biochar could promote plant growth and alleviate apple replant disease by reducing the growth of harmful soil microorganisms,changing soil microbial community structure and improving the soil environment.This experiment included five treatments:apple replant soil(CK),methyl bromide fumigation apple replant soil(FM),replant soil with biochar addition(2%),replant soil with F.oxysporum spore solution(8×10^(7)spores·mL^(-1)),and replant soil with biochar and F.oxysporum spore solution addition.Seedling biomass,the activity of antioxidant enzymes in the leaves and roots,and soil environmental variables were measured.Microbial community composition and community structure were analyzed using 16SrDNA and ITS2 gene sequencing.Biochar significantly reduced the abundance of F.oxysporum and increased soil microbial diversity and richness.Biochar also increased the soil enzyme activities(urease,invertase,neutral phosphatase,and catalase),the biomass(plant height,fresh weight,dry weight)and the activity of antioxidant enzymes(superoxide dismutase,peroxidase,and catalase).The root indexes of apple seedlings was also increased in replant soil by biochar.In sum,biochar promoted the growth of plants,improved the replant soil environment,and alleviated apple replant disease.展开更多
基金funded by the Natural Science Foundation of China(Grant Nos.32230097 and 32172512)the Jiangsu Agricultural Science and Technology Innovation Fund[Grant No.CX(20)2023]+1 种基金the Jiangsu Special Fund for Frontier Foundation Research of Carbon Peaking and Carbon Neutralization(Grant No.BK20220005)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘5-Aminolevulinic acid(ALA),is a novel plant growth regulator that can enhance plant tolerance against salt stress.However,the molecular mechanism of ALA is not well studied.In this study,ALA improved salt tolerance of apple(Malus×domestica'Gala')when the detached leaves or cultured calli were used as the materials.The expression of MdWRKY71,a WRKY transcription factor(TF)gene was found to be responsive to NaCl as well as ALA treatment.Functional analysis showed that overexpressing(OE)-MdWRKY71 significantly improved the salt tolerance of the transgenic apple,while RNA interfering(RNAi)-MdWRKY71 reduced the salt tolerance.However,exogenous ALA alleviated the salt damage in the RNAi-MdWRKY71 apple.When MdWRKY71 was transferred into tobacco,the salt tolerance of transgenic plants was enhanced,which was further improved by exogenous ALA.Subsequently,MdWRKY71 bound to the W-box of promoters of MdSOS2,MdNHX1,MdCLC-g,MdSOD1,MdCAT1 and MdAPX1,transcriptionally activating the gene expressions.Since the genes are responsible for Na+and Cl-transport and antioxidant enzyme activity respectively,it can be concluded that MdWRKY71,a new TF,is involved in ALA-improved salt tolerance by regulating ion homeostasis and redox homeostasis.These results provided new insights into the transcriptional regulatory mechanism of ALA in enhancing apple salt tolerance.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.32122080,31972375)Shandong Province(Grant No.ZR2020YQ25)。
文摘The content of soluble sugars is a vital parameter that indicates the quality of fleshy fruits such as apple(Malus domestica Borkh.).Studying the patterns of accumulation of soluble sugars and regulatory mechanisms associated with fruit development is crucial for breeding improved fruit varieties.Here,we report that MdCIbHLH1,a low temperature-induced b HLH transcription factor,inhibits the accumulation of soluble sugars by regulating sugar-metabolizing enzyme activities,photosynthetic performance,and the expression of sugar-related genes in developing apple fruits.MdCIbHLH1 inhibits MdFBP and MdPEPCK expression,thus blocking the conversion of acids to sugars in apple fruits.We also discovered that MdCIbHLH1 decreases the photosynthetic rate and carbohydrate accumulation in apple leaves.Our results suggest that soluble sugar accumulation in apple fruits is influenced by multiple factors,including metabolic status,photosynthesis,and carbohydrate allocation.MdCIbHLH1 is critically involved in controlling the accumulation of soluble sugars by coordinating carbohydrate synthesis and allocation,thus influencing sugar transport and its metabolism during the development of apple fruits.
基金supported by the earmarked fund for the China Agriculture Research System(CARS-27)the National Natural Science Foundation of China(31972389)the Key S&T Special Projects of Shaanxi Province,China(2020zdzx03-01-02)。
文摘Cadmium(Cd)stress is a serious threat to apple growth and development.Ethylene response factors(ERFs)are a major family of transcription factors(TFs)that play a key role in the resistance to Cd stress.In this study,we found that the ERF TF Md ERF114 was induced in response to Cd stress.The overexpression of Md ERF114 in apple(Malus domestica)roots reduced the accumulation of Cd in the plants and enhanced their tolerance to Cd stress.Yeast one-hybrid(Y1H)assays,dual-luciferase assays,and electrophoretic mobility shift assays indicated that MdERF114 directly binds to the promoter of MdATG16 and activates its expression to increase autophagic activity,which leads to higher resistance to Cd stress.In addition,MdMYB306 interacts with MdERF114 and enhances the resistance to Cd stress by promoting the binding of MdERF114 to the promoter of MdATG16.Our findings reveal an important mechanism by which MdMYB306-MdERF114-MdATG16 influences the resistance of apple to Cd stress.
基金supported by the Natural Science Foundation of China(Grant No.32172512)the Jiangsu Special Fund for Frontier Foundation Research of Carbon Peaking and Carbon Neutralization(Grant No.BK20220005)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘5-Aminolevulinic acid(ALA)is a novel plant growth regulator that has shown outstanding capability to promote stomatal opening.Starch degradation,catalyzed byβ-amylase(EC3.2.1.2,BAM),plays an important role in stomatal opening.However,whether the starch breakdown is involved in ALA-regulating stomatal movement is unclear.In the current study,we found that exogenous ALA effectively stimulated the starch breakdown in guard cells,increasedβ-amylase activity and promoted stomatal opening in leaves of apple(Malus×domestica).Based on genome-wide identification,we identified a total of 119 members of BAM gene family in ten commonly Rosaceae crops.Analyses of gene structure,motif identification,and gene pair collinearity revealed relative conservation among members within the same group or subgroup.Among these genes,MdBAM17 and other 12 genes were identified as the orthologous genes of AtBAM1,which is responsible for starch degradation to modulate the stomatal movement in Arabidopsis.qRT-PCR analysis revealed a positive correlation between the expressions of MdBAM17 and stomatal aperture,as well asβ-amylase activity,whereas a negative correlation was observed with the starch content.Subcellular localization analysis confirmed that MdBAM17 is a chloroplast protein,consistent with the AtBAM1.MdBAM17 was mainly expressed in guard cells and responsive to exogenous ALA.Overexpressing MdBAM17 increasedβ-amylase activity and promoted starch breakdown,leading to stomatal opening,which was further strengthened by ALA.RNA-interfering MdBAM17 decreasedβ-amylase activity,resulting in starch accumulation,and impairing the stomatal opening by ALA.However,modulation of MdBAM17 expression did not affect the levels of flavonols and H_(2)O_(2)in guard cells,suggesting that MdBAM17-promoted starch degradation may function at downstream of ROS signaling in the ALAregulated stomatal opening.Our findings provide new insights into the mechanisms of ALA-regulated stomatal movement.
基金supported by a project grant from the Key Research and Development and Promotion Projects of Henan Province,China(212102110113)the Special Fund for Henan Agriculture Research System,China(HARS-22-09-Z2).
文摘Apple replant disease is a complex soil syndrome that occurs when the same fields are repeatedly utilized for apple orchard cultivation.It can be caused by various pathogens,and Fusarium solani is the main pathogen.Fusarium solani disrupts the structure and function of the orchard soil ecosystem and inhibits the growth and development of apple trees,significantly impacting the quality and yield of apples.In this study,we conducted a transcriptome comparison between uninoculated apple saplings and those inoculated with F:solani.The differentially expressed genes were mainly enriched in processes such as response to symbiotic fungus.Plant defensins are antimicrobial peptides,but their roles during F.solani infection remain unclear.We performed a genome-wide identification of apple defensin genes and identified 25 genes with the conserved motif of eight cysteine residues.In wildtype apple rootstock inoculated with F.solani,the root surface cells experienced severe damage,and showed significant differences in the total root length,total root projection area,root tips,root forks,and total root surface area compared to the control group.qRT-PCR analysis revealed that MdDEF3 and MdDEF25 were triggered in response to F.solani infection in apples.Subcellular localization showed specific expression of the MdDEF3-YFP and MdDEF25-YFP proteins on the cell membrane.Overexpressing theMdDEF25-YFP fusiongene enhanced resistance against F.solani in apple,providing a new strategy for the future prevention and biological control of apple replantdisease.
文摘Cashew processing in Côte d’Ivoire focuses only on the cashew nut, to the detriment of the apple. Only a very small proportion of the apple is processed into juice. The aim of this work is to enhance the value of cashew apples by transforming them into jam. Specifically, the aim was first to characterize the sensory properties of cashew apple jam formulations using baobab powder as a source of pectin and then to optimise the formulations. A Box-Behken design with pH, Sugar, and Baobab as factors was used to model and characterize the jam sensory descriptors, and a multivariate analysis with SensomineR was used to characterize the jam formulations. The desirability function was used to optimise the formulations. The results show globally significant regressions at the 0.05 threshold for the sensory descriptors Gelling, Brilliance, Smell, Sweetness, and (-)Astringency, with the exception of (-)Salinity. The R2 coefficients are greater than 80%. The factors studied could have effects on the sensory descriptors of cashew jam formulations. The Baobab had the main effect on the gelling, smell, and astringency of the jams. Brilliance depended on the added sugar. A product effect (p < 0.001) was observed for the descriptors Smell, Gelling, Brilliance, and Sweetness, as these allowed the panelists to find differences between the formulations. Optimum jam formulation can be achieved with 51.56% sugar and 2.12% Baobab at a pH of 3.15. Cashew apple jam using Baobab offers opportunities to add value to apples that have long been abandoned in the field. It would be important to find conditions for prolonged storage of this jam.
基金supported by grants from the National Key Research and Development Program of China(Grant Nos.2023YFD2301000,2022YFD2100102)National Natural Science Foundation of China(Grant No.32302616)+1 种基金Shandong Province(Grant No.ZR2023QC032)the Key Research and Development Program of Shandong Province(Grant No.2023CXGC010709).
文摘Chlorogenic acid(CGA),a potent antioxidant with antimicrobial,antiviral,and metabolic regulatory properties,plays multifunctional roles in apple fruit by enhancing postharvest quality,extending shelf life through oxidative stress reduction,and inhibiting enzymatic browning to preserve color,flavor,and nutritional integrity.Despite the established role of hydroxycinnamoyl transferase(HCT)as a rate-limiting enzyme in CGA biosynthesis,the specific HCT gene responsible for this process and its regulatory mechanisms remain elusive.To address this knowledge gap,we systematically investigated CGA accumulation dynamics during apple storage and functionally characterized MdHCT6,a candidate gene within the HCT family.We found that the chlorogenic acid content in apple fruit increased significantly during postharvest storage compared with the initial storage.Transcriptome analysis showed that the expression level of MdHCT6 was significantly higher than that of other HCT homologues,which was consistent with the reverse transcription quantitative PCR(RT-qPCR)results.In vitro enzymatic assays demonstrated that MdHCT6 catalyzes the synthesis of chlorogenic acid using shikimic acid and quinic acid as precursors,while genetic evidence confirmed its role as a key positive regulator of chlorogenic acid accumulation in apples.Furthermore,we identified the transcription factor MdMYB93 as a direct upstream activator of MdHCT6,establishing a regulatory cascade that governs CGA production.This work not only deciphers the molecular hierarchy of CGA biosynthesis in apples but also provides actionable targets for genetic improvement of antioxidant capacity and postharvest resilience in apple germplasm.
文摘Apple polyphenols are widely present in apple pulp,peel,kernel,and leaves.They are natural bioactive substances with a variety of health functions.This review describes the antioxidant functions of anthocyanins,quercetin,phlorizin,chlorogenic acid,and epicatechin in apple polyphenols through the regulation of signal pathways and transcription factors,and the inhibition or induction of enzymes.Massive food applications of apple polyphenols are summarized,including excellent color protection of fruits and vegetables,meat preservation,preparation of composite packaging fi lms as active ingredients,enhancement of nutritional value as functional ingredients,and improvement of food taste and physical stability.This review would provide a reference for the exploration of apple polyphenol resources and its development in the food field.
基金funded by the National Key R&D Program of China(2023YFD1401401)the China Agriculture Research System(CARS27)。
文摘Defensin,an essential component of plant development,is indispensable in pathogen resistance.However,the molecular function of defensins under pathological conditions of Cytospora canker has not been characterized in apple plants.The present study exhibits a detailed overview of the phylogeny and structure of 29 defensins(MdDEF)in apple.Expression analysis revealed that MdDEF genes were spatiotemporally diverse across apple tissues.Five MdDEF genes were found to be significantly up-regulated following a challenge with Cytospora mali.The transgenic overexpression of five defensin genes in apple calli enhanced resistance to C.mali.Among them,MdDEF30 was strongly induced and conferred the highest resistance level in vivo.Meanwhile,antifungal activity assays in vitro demonstrated that a recombinant protein produced from MdDEF30could inhibit the growth of C.mali.Notably,MdDEF30 promoted the accumulation of reactive oxygen species(ROS)and activated defense-related genes such as PR4,PR10,CML13,and MPK3.Co-expression regulatory network analysis showed that MdWRKY75 may regulate the expression of MdDEF30.Further yeast onehybrid(Y1H),luciferase,and chromatin Immunoprecipitation quantitative polymerase chain reaction(ChIPqPCR)assays verified that MdWRKY75 could directly bind to the promoter of MdDEF30.Importantly,pathogen inoculation assays confirmed that MdWRKY75 positively regulates resistance by transcriptionally activating MdDEF30.Overall,these results demonstrated that MdDEF30 promotes resistance to C.mali in apple plants and that MdWRKY75 regulates MdDEF30 expression during the induction of resistance,thereby clarifying biochemical mechanisms of resistance to C.mali in apple trees.
基金Supported by High-end Talent Project of Hebei ProvinceTangshan Talent Funding Project(B202302006).
文摘[Objectives]This study was conducted to investigate the physicochemical and functional properties of soluble dietary fiber(SDF)from apple pomace.[Methods]Soluble dietary fiber(SDF)from apple pomace was extracted by direct water extraction(W),lactic acid bacteria fermentation(F)and steam explosion(SE)respectively,and the extraction methods and physicochemical and functional characteristics were compared and analyzed.[Results]The solubility,water holding capacities,oil holding capacities and swelling capacities of W-SDF,F-SDF and SE-SDF were(2.13,3.95 and 5.13 g/g),(9.02,13.75 and 15.88 g/g),(2.13,4.08 and 5.11 g/g),and(10.82,14.03 and 15.77 ml/g),respectively.Their emulsifying activity,emulsifying stability and least gelation concentration were(30.28,47.95 and 58.72 ml/100 ml),(37.88,45.25 and 57.13 ml/100 ml),and(12.11,11.25 and 9.87%),respectively.The adsorption capacities of W-SDF,F-SDF and SE-SDF for heavy metals(Pb,As and Cu)in the intestinal environment(pH 7)were(162.7,183.5 and 197.3μmol/g),(132.8,156.7 and 168.9μmol/g),and(57.2,63.5 and 89.2μmol/g)respectively.In the gastric environment(pH 2),they were(72.8,110.5,138.9μmol/g),(82.1,112.5,135.7μmol/g),and(38.9,42.7,55.1μmol/g)respectively.[Conclusions]The study can provide a theoretical basis for functional modification and comprehensive utilization of dietary fiber from apple pomace.
基金supported by the National Natural Science Foundation of China (32272384)the Natural Science Foundation of Shandong Province, China (ZR2020MC149)。
文摘Ethylene response factors 2(ERF2) are essential for plant growth, fruit ripening, metabolism, and resistance tostress. In this study, the expression levels of the genes for MdERF2 implicated in the biosynthesis, compositionand ultrastructure of fruit cuticular wax in apple(Malus domestica) were studied by the transfection of apple fruitand/or calli with MdERF2-overexpression(ERF2-OE) and MdERF2-interference(ERF2-AN) vectors. In addition,the direct target genes of MdERF2 related to wax biosynthesis were identified using electrophoretic mobility shiftassays(EMSAs) and dual-luciferase reporter(DLR) assays. The findings indicated that the expression levels offour wax biosynthetic genes, long-chain acyl-CoA synthetase 2(MdLACS2), eceriferum 1(MdCER1), eceriferum4(MdCER4), and eceriferum 6(MdCER6), were upregulated by ERF2-OE. In contrast, the expression levels ofthese genes were inhibited when MdERF2 was silenced. Furthermore, the overall structure and accumulationof fruit cuticular wax were influenced by the expression level of MdERF2. Treatment with ERF2-OE significantlyincreased the proportions of alkanes and ketones and reduced the proportions of fatty acids and esters. In addition,the EMSAs and DLR assays demonstrated that MdERF2 could bind directly to GCC-box elements in the promotersof MdLACS2, MdCER1, and MdCER6 to activate their transcription. These results confirmed that MdERF2 targetsthe up-regulation of expression of the MdLACS2, MdCER1, and MdCER6 genes, thereby altering the composition,content, and microstructure of apple epidermal wax.
基金supported by the National Natural Science Foundation of China(Grant No.31672104)the earmarked fund for China Agriculture Research System(Grant No.CARS-27)+1 种基金Taishan Scholar Funded Project(Grant No.20190923)Natural Science Foundation of Shandong Province(Grant No.ZR2020MC131)。
文摘The cultivation of apples in replanted orchards is essential given limitations in land resources.However,the presence of Fusarium and phenolic acids in the replanted soil harms the soil environment,which impedes the sustainable development of the apple industry.In this study,earthworm was used as the fermentation precursor protein to optimize the fermentation conditions,and the inhibition mechanism of the fermentation product on Fusarium and its potential to repair the apple replant soil environment were explored.Laboratory experiments showed that the optimum initial pH,temperature and time of earthworm fermentation were 7,37℃ and 10 d,respectively.The inhibition rates of earthworm fermentation products against F.oxysporum,F.solani,F.proliferatum,and F.moniliforme were 79.8%,75.1%,78.7%and 79.2%,respectively.The inhibition rates of spore germination on F.oxysporum,F.solani,F.proliferatum,and F.moniliforme were 83.8%,87.3%,83.2%and84.8%,respectively.In the field,use 300 mL of earthworm fermentation products for each planting pits before planting.The experimental results showed that,compared with the control,the content of soil pathogenic Fusarium and phenolic acid in Wantou(W3)were decreased by75.1%and 59.8%,respectively,after treatment with earthworm fermentation products in 2019.Soil urease,phosphatase,sucrase and catalase activities increased by 383.2%,78.2%,130.3%and 43.5%,respectively.The fruit weight,anthocyanin content,soluble sugar,sugar-acid ratio,total ester ratio,total ester concentration and yield increased by 80.7%,60.6%,25.6%,50.3%,19.7%,262.4%and 193.5%,respectively,while titratable acid content decreased by 16.9%.In conclusion,earthworm fermentation products can be used as a sustainable amendment to control apple replant disease.
基金financially supported by the National Natural Science Foundation of China(Grant No.32202463)China Agriculture Research System(Grant No.CARS-27)the Agricultural Science and Technology Innovation Program(Grant No.CAAS-ASTIP-2021-RIP-02)。
文摘Apple leaf spot,caused by the Alternaria alternata apple pathotype(AAAP),is an important fungal disease of apple.To understand the molecular basis of resistance and pathogenesis in apple leaf spot,the transcriptomes of two apple cultivars‘Hanfu'(HF)(resistant)and‘Golden Delicious'(GD)(susceptible)were analyzed at 0,6,18,24 and 48 h after AAAP inoculation by RNA-Seq.At each time point,a large number of significantly differentially expressed genes(DEGs)were screened between AAAP-inoculated and uninoculated apple leaves.Analysis of the common DEGs at four time points revealed significant differences in the resistance of‘HF'and‘GD'apple to AAAP infection.RLP,RNL,and JA signal-related genes were upregulated in both cultivars to restrict AAAP development.However,genes encoding CNLs,TNLs,WRKYs,and AP2s were only activated in‘HF'as part of the resistance response,of which,some play major roles in the regulation of ET and SA signal transduction.Further analysis showed that many DEGs with opposite expression trends in the two hosts may play important regulatory roles in response to AAAP infection.Transient expression of one such gene MdERF110 in‘GD'apple leaves improved AAAP resistance.Collectively,this study highlights the reasons for differential resistance to AAAP infection between‘HF'and‘GD'apples which can theoretically assist the molecular breeding of disease-resistant apple crops.
基金supported by grants from the Natural Science Foundation of Hebei Province(Grant No.C2022204086)the Hebei Apple Innovation Team of Modern Agricultural Industry Technology System(Grant No.HBCT2021100211)the National Natural Science Foundation of China(Grant No.32072524).
文摘Abiotic stress reduces plant yield and quality.WRKY transcription factors play key roles in abiotic stress responses in plants,but the molecular mechanisms by which WRKY transcription factors mediate responses to drought and osmotic stresses in apple(Malus×domestica Borkh.)remain unclear.Here,we functionally characterized the apple GroupⅢWRKY gene MdWRKY115.qRT-PCR analysis showed that MdWRKY115 expression was up-regulated by drought and osmotic stresses.GUS activity analysis revealed that the promoter activity of MdWRKY115 was enhanced under osmotic stress.Subcellular localization and transactivation assays indicated that MdWRKY115 was localized to the nucleus and had a transcriptional activity domain at the N-terminal region.Transgenic analysis revealed that the overexpression of MdWRKY115 in Arabidopsis plants and in apple callus markedly enhanced their tolerance to drought and osmotic stresses.DNA affinity purification sequencing showed that MdWRKY115 binds to the promoter of the stress-related gene MdRD22.This binding was further verified by an electrophoretic mobility shift assay.Collectively,these findings suggest that MdWRKY115 is an important regulator of osmotic and drought stress tolerance in apple.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000307)the National Natural Science Foundation of China(Grant No.32172529)+2 种基金the Special Funds for Major Scientific and Technological Innovation from Shaanxi Province(Grant No.2020zdzx03-0101)the Earmarked Fund for China Agriculture Research System(Grant No.CARS-27)China Postdoctoral Science Foundation(Grant Nos.2017M610657,2018T111108)。
文摘Auxin is throughout the entire life process of plants and is involved in the crosstalk with other hormones,yet its role in apple disease resistance remains unclear.In this study,we investigated the function of auxin/indole-3-acetic acid(IAA)gene Md IAA24 overexpression in enhancing apple resistance to Glomerella leaf spot(GLS)caused by Colletotrichum fructicola(Cf).Analysis revealed that,upon Cf infection,35S::Md IAA24 plants exhibited enhanced superoxide dismutase(SOD)and peroxidase(POD)activity,as well as a greater amount of glutathione(reduced form)and ascorbic acid accumulation,resulting in less H_(2)O_(2)and superoxide anion(O_(2)^(-))in apple leaves.Furthermore,35S::Md IAA24 plants produced more protocatechuic acid,proanthocyanidins B1,proanthocyanidins B2 and chlorogenic acid when infected with Cf.Following Cf infection,35S::Md IAA24 plants presented lower levels of IAA and jasmonic acid(JA),but higher levels of salicylic acid(SA),along with the expression of related genes.The overexpression of Md IAA24 was observed to enhance the activity of chitinase andβ-1,3-glucanase in Cfinfected leaves.The results indicated the ability of Md IAA24 to regulate the crosstalk between IAA,JA and SA,and to improve reactive oxygen species(ROS)scavenging and defense-related enzymes activity.This jointly contributed to GLS resistance in apple.
基金supported in part by the General Program Hunan Provincial Natural Science Foundation of 2022,China(2022JJ31022)the Undergraduate Education Reform Project of Hunan Province,China(HNJG-20210532)the National Natural Science Foundation of China(62276276)。
文摘Accurate diagnosis of apple leaf diseases is crucial for improving the quality of apple production and promoting the development of the apple industry. However, apple leaf diseases do not differ significantly from image texture and structural information. The difficulties in disease feature extraction in complex backgrounds slow the related research progress. To address the problems, this paper proposes an improved multi-scale inverse bottleneck residual network model based on a triplet parallel attention mechanism, which is built upon ResNet-50, while improving and combining the inception module and ResNext inverse bottleneck blocks, to recognize seven types of apple leaf(including six diseases of alternaria leaf spot, brown spot, grey spot, mosaic, rust, scab, and one healthy). First, the 3×3 convolutions in some of the residual modules are replaced by multi-scale residual convolutions, the convolution kernels of different sizes contained in each branch of the multi-scale convolution are applied to extract feature maps of different sizes, and the outputs of these branches are multi-scale fused by summing to enrich the output features of the images. Second, the global layer-wise dynamic coordinated inverse bottleneck structure is used to reduce the network feature loss. The inverse bottleneck structure makes the image information less lossy when transforming from different dimensional feature spaces. The fusion of multi-scale and layer-wise dynamic coordinated inverse bottlenecks makes the model effectively balances computational efficiency and feature representation capability, and more robust with a combination of horizontal and vertical features in the fine identification of apple leaf diseases. Finally, after each improved module, a triplet parallel attention module is integrated with cross-dimensional interactions among channels through rotations and residual transformations, which improves the parallel search efficiency of important features and the recognition rate of the network with relatively small computational costs while the dimensional dependencies are improved. To verify the validity of the model in this paper, we uniformly enhance apple leaf disease images screened from the public data sets of Plant Village, Baidu Flying Paddle, and the Internet. The final processed image count is 14,000. The ablation study, pre-processing comparison, and method comparison are conducted on the processed datasets. The experimental results demonstrate that the proposed method reaches 98.73% accuracy on the adopted datasets, which is 1.82% higher than the classical ResNet-50 model, and 0.29% better than the apple leaf disease datasets before preprocessing. It also achieves competitive results in apple leaf disease identification compared to some state-ofthe-art methods.
基金supported by China Agriculture Research System of MOF and MARA (Grant No.CARS-27)Shandong Agricultural Major Applied Technology Innovation Project (Grant No.SD2019ZZ008)+5 种基金Qingchuang Science and Technology Support Project of Shandong Colleges and Universities (Grant No.2019KJF020)Natural Science Foundation of Shandong Province (Grant No.ZR2020MC131)the National Key Research and Development Program of China (Grant No.2020YFD1000201)Taishan Scholars Funded Project (Grant No.ts20190923)the National Natural Science Foundation of China (Grant No.32072510)the Fruit Innovation Team in Shandong Province,China (Grant No.SDAIT-06-07)。
文摘Apple replant disease(ARD) is primarily caused by biotic factors that seriously inhibits the development of apple industry. Therefore, the use of biological control measures to inhibit the main pathogens(such as Fusarium spp.) that cause ARD is of great significance to the sustainable development of the apple industry. Trichoderma virens 6PS-2, which exhibited antagonism toward a variety of pathogens, was screened from the rhizosphere soils of healthy apple trees(Malus robusta) in different replanted orchards in the Yantai and Zibo Cities, Shandong Province, China. Its fermentation extract inhibited the growth of pathogenic Fusarium proliferatum f. sp. Malus domestica MR5, which was proportional to the concentration. These substances also increased the hairy root volume and growth of Arabidopsis thaliana lateral roots. The phenotype of Malus hupehensis seedlings and microbial community structure in rhizosphere soils in greenhouse experiment using Highthroughput sequencing were analyzed, and the field experiment with grafted apple trees were used for further verification. Compared with the application of potato dextrose broth(PDB) medium, application of 6PS-2 spore suspension directly to replanted soils could improve the growth of M. hupehensis seedlings as well as the elongation of grafted apple trees. Concomitant decreases in the gene copy number of Fusarium and increases in the culturable bacteria/fungi were also observed in the greenhouse and field experiments. The abundance of Trichoderma,Bacillus, and Streptomyces increased significantly, but that of Fusarium, Pseudarthrobacter, and Humicola decreased. The content of esters, phenols,furans, and amino acids in root exudates of M. hupehensis seedlings increased, which significantly inhibited the multiplication of Fusarium, but was positively correlated with Bacillus and Trichoderma. In summary, T. virens 6PS-2 not only directly inhibits the activity of pathogenic Fusarium but also secrets secondary metabolites with antifungal and growth-promoting potential. In addition, 6PS-2 spore suspension can also promote the growth of plants to a certain extent, and change the soil microbial community structure of rhizosphere soils. It is believed that T. virens 6PS-2 has the potential for the alleviation of apple replant disease(ARD) in China.
基金supported by the earmarked fund for National Natural Science Foundation of China(Grant No.31801816)National Modern Agro-industry Technology Research System(Grant No.CARS-27)Taishan scholar funded project(Grant No.TS20190923)。
文摘Apple replant disease(ARD)negatively affects plant growth and reduces yields in replanted orchards.In this study,biochar was applied to apple replant soil with Fusarium oxysporum.Our aim was to investigate whether biochar could promote plant growth and alleviate apple replant disease by reducing the growth of harmful soil microorganisms,changing soil microbial community structure and improving the soil environment.This experiment included five treatments:apple replant soil(CK),methyl bromide fumigation apple replant soil(FM),replant soil with biochar addition(2%),replant soil with F.oxysporum spore solution(8×10^(7)spores·mL^(-1)),and replant soil with biochar and F.oxysporum spore solution addition.Seedling biomass,the activity of antioxidant enzymes in the leaves and roots,and soil environmental variables were measured.Microbial community composition and community structure were analyzed using 16SrDNA and ITS2 gene sequencing.Biochar significantly reduced the abundance of F.oxysporum and increased soil microbial diversity and richness.Biochar also increased the soil enzyme activities(urease,invertase,neutral phosphatase,and catalase),the biomass(plant height,fresh weight,dry weight)and the activity of antioxidant enzymes(superoxide dismutase,peroxidase,and catalase).The root indexes of apple seedlings was also increased in replant soil by biochar.In sum,biochar promoted the growth of plants,improved the replant soil environment,and alleviated apple replant disease.
