Understanding the molecular responses of tea leaves to mechanical stress is crucial for elucidating the mechanisms of post-harvest quality formation during oolong tea processing.This study employed an integrated multi...Understanding the molecular responses of tea leaves to mechanical stress is crucial for elucidating the mechanisms of post-harvest quality formation during oolong tea processing.This study employed an integrated multi-omics strategy to characterize the changes and interactions among metabolomic(MB),transcriptomic(TX),and proteomic(PT)profiles in mechanically stressed tea leaves.Mechanical stress initially activated damage-associated molecular patterns(DAMPs),including Ca^(2+)signaling,jasmonic acid signaling,and glutathione metabolism pathways.These processes subsequently induced quality-related metabolic pathways(QRMPs),particularly α-linolenic acid and phenylalanine metabolism.Upregulated expression of LOX,ADH1,and PAR genes,together with the increased abundance of their encoded proteins,respectively promoted the accumulation of jasmine lactone,benzyl alcohol,and 2-phenylethanol.These findings indicate that mechanical stress influences the metabolite biosynthesis in tea leaves through coordinated molecular responses.This study provides new insights into the molecular mechanisms underlying tea leaf responses to mechanical stress and a foundation for future investigations into how early molecular events may contribute to post-harvest metabolic changes during oolong tea processing.展开更多
Animals promote their survival by avoiding rapidly approaching objects that indicate threats.It is believed that looming cues are detected by retinal ganglion cells(RGCs)that project to the superior colliculus(SC).How...Animals promote their survival by avoiding rapidly approaching objects that indicate threats.It is believed that looming cues are detected by retinal ganglion cells(RGCs)that project to the superior colliculus(SC).However,the exact type of RGC that transmits looming-related signals remains unclear.Here we identify a specific transient type of RGCs that controls mouse looming-evoked defensive response by sending axonal collaterals to the dorsal raphe nucleus(DRN)and SC.Looming signals transmitted by DRN-projecting RGCs activate DRN GABA neurons and in turn inhibit serotonin neurons.Moreover,optogenetically stimulating serotonin neurons reduces looming-evoked defensive behaviors.Thus,a dedicated population of RGCs detects rapidly approaching visual threats and their input to the DRN controls a serotonergic self-gating mechanism that regulates innate defensive responses.Our study provides new insights into how DRN and SC work in concert to extract and translate visual threats into defensive behavioral responses.展开更多
Jasmonic acid （JA） is an important phytohormone that regulates plant defense responses against herbivore attack, pathogen infection and mechanical wounding. In this report, we provided biochemical and genetic eviden...Jasmonic acid （JA） is an important phytohormone that regulates plant defense responses against herbivore attack, pathogen infection and mechanical wounding. In this report, we provided biochemical and genetic evidence to show that the Arabidopsis thaliana NAC family proteins ANAC019 and ANAC055 might function as transcription activators to regulate JA-induced expression of defense genes. The role of the two NAC genes in JA signaling was examined with the anacO19 anac055 double mutant and with transgenic plants overexpressing ANACO19 or ANAC055. The anacO19 anac055 double mutant plants showed attenuated JA-induced VEGETATIVE STORAGE PROTEIN1 （VSP1） and LIPOXYGENASE2 （LOX2） expression, whereas transgenic plants overexpressing the two NAC genes showed enhanced JA-induced VSP1 and LOX2 expression. That the JA-induced expression of the two NAC genes depends on the function of COIl and AtMYC2, together with the finding that overexpression of ANACO19 partially rescued the JA-related phenotype of the atmyc2-2 mutant, has led us to a hypothesis that the two NAC proteins act downstream of AtMYC2 to regulate JA-signaled defense responses. Further evidence to substantiate this idea comes from the observation that the response of the anacO19 anac055 double mutant to a necrotrophic fungus showed high similarity to that of the atmyc2-2 mutant.展开更多
Although there were reports suggesting the involvement of endogenous cAMP in plant defense signaling cascades, there is no direct evidence supporting this notion yet and the detailed mechanism is unclear. In the prese...Although there were reports suggesting the involvement of endogenous cAMP in plant defense signaling cascades, there is no direct evidence supporting this notion yet and the detailed mechanism is unclear. In the present study, we have used pathogenic fungi Verticillium dahliae and Arabidopsis plants as a model system of plant-microb interaction to demonstrate the function of endogenous cAMP in Arabidopsis defense responses. Both V. dahliae inoculation and Verticillium toxins injection induced typical “wilt” symptoms in Arabidopsis seedlings. When either 8-Br-AMP (a membrane permeable cAMP analogue) or salicylic acid (SA) was applied to Arabidopsis, the plants became resistant to V. dahliae toxins. However, addition of 8-Br-AMP did not increase the resistance of Arabidopsis transgenic plants deficient in SA to the toxins, suggesting that cAMP might act upstream of SA in plant defense signaling pathway. Indeed, 8-Br-cAMP and forskolin, an activator of adenylyl cyclase, significantly stimulated the endogenous SA level in plants, whereas DDA, an inhibitor of adenylyl cyclase dramatically reduced toxin-induced SA increase. Both the endog- enous cAMP and SA increased significantly in Arabidopsis seedlings treated with toxins. Furthermore, transcription level of pathogenesis-related protein 1 gene (PR1) was strongly induced by both 8-Br-cAMP and the toxin treatment. Taken together, our data demonstrate that endogenous cAMP is involved in plant defense responses against Verticillium- secreted toxins by regulating the production of the known signal SA in plant defense pathway.展开更多
Phenotypical, cytological and molecular responses of rice to the fungus Magnaporthe grisea were studied using rice cultivars and lesion mimic plants. The cultivar Katy was susceptible to several virulent M. grisea iso...Phenotypical, cytological and molecular responses of rice to the fungus Magnaporthe grisea were studied using rice cultivars and lesion mimic plants. The cultivar Katy was susceptible to several virulent M. grisea isolates, and a Sekiguchi like-lesion mimic mutant of Katy （LmmKaty） showed enhanced resistance to these isolates. Lesion mimic phenotype of LmmKaty was rapidly induced by virulent M. grisea isolates or by avirulent ones only at high levels of inoculum. Autofluorescence （a sign of an active defense response） was visible under ultraviolet light 24 h after localized inoculation in the incompatible interaction, whereas, not evident in the compatible interaction. Autofluorescence was also observed in LmmKaty 20 h after pathogen inoculation, indicating that rapid cell death is a mechanism of LmmKaty to restrict pathogen invasion. Rapid accumulations of defense related （DR） gene transcripts, phenylalanine ammonia lyase and β-glucanase, were observed beginning at 6 h and were obvious at 16 h and 24 h after inoculation in an incompatible interaction. Rapid transcript accumulations of PR-1 and chitinase had occurred by 24 h after inoculation in an incompatible interaction. Accumulations of these transcripts were delayed in the compatible interaction. These results indicate that host active defense responses occur 24 h after pathogen inoculation and that LmmKaty exhibits enhanced resistance to M. grisea. It is suggested that the autofluorescence and expression of the DR genes after heavy inoculation are important cytological and molecular markers respectively for early determination of the host response to M. grisea in the rice blast system.展开更多
The soil-borne necrotrophic fungus Rhizoctonia solani is one of destructive fungi causing severe yield losses in various important crops. However, the host defense mechanisms against the invasion of this pathogen are ...The soil-borne necrotrophic fungus Rhizoctonia solani is one of destructive fungi causing severe yield losses in various important crops. However, the host defense mechanisms against the invasion of this pathogen are poorly understood. In this study, we employed an i TRAQ-based quantitative proteomic approach to investigate host proteins responsive to R. solani using the resistant rice cultivar YSBR1. As a whole, we identified 319 differentially accumulated proteins(DAPs) after inoculation of rice plants with R. solani. Functional categorization analysis indicates that these DAPs cover a broad range of functions. Notably, a substantial portion of the DAPs are involved in cell redox homeostasis, carbohydrate metabolism, and phenylpropanoid biosynthesis, or belong to pathogenesis-related proteins, indicating that these processes/proteins play important roles in host defense against R. solani. Interestingly, all of the DAPs involved in photosynthesis and chlorophyll biosynthetic processes, and part of the DAPs involved in phenylpropanoid biosynthesis, show reduced accumulation after R. solani infection, suggesting that R. solani probably inhibits host photosynthetic system and phenylpropanoid biosynthesis to facilitate infection and colonization. In conclusion, our results provide both valuable resources and new insights into the molecular mechanisms underlying rice and R. solani interaction.展开更多
Parvalbumin-positive retinal ganglion cells(PV+RGCs)are an essential subset of RGCs found in various species.However,their role in transmitting visual information remains unclear.Here,we characterized PV+RGCs in the r...Parvalbumin-positive retinal ganglion cells(PV+RGCs)are an essential subset of RGCs found in various species.However,their role in transmitting visual information remains unclear.Here,we characterized PV+RGCs in the retina and explored the functions of the PV+RGC-mediated visual pathway.By applying multiple viral tracing strategies,we investigated the downstream of PV+RGCs across the whole brain.Interestingly,we found that the PV+RGCs provided direct monosynaptic input to PV+excitatory neurons in the superficial layers of the superior colliculus(SC).Ablation or suppression of SC-projecting PV+RGCs abolished or severely impaired the flight response to looming visual stimuli in mice without affecting visual acuity.Furthermore,using transcriptome expression profiling of individual cells and immunofluorescence colocalization for RGCs,we found that PV+RGCs are predominant glutamatergic neurons.Thus,our findings indicate the critical role of PV+RGCs in an innate defensive response and suggest a non-canonical subcortical visual pathway from excitatory PV+RGCs to PV+SC neurons that regulates looming visual stimuli.These results provide a potential target for intervening and treating diseases related to this circuit,such as schizophrenia and autism.展开更多
A number of plant pathogenic species of Phytophthora are known to produce different classes of secretory proteins during interactions with their hosts.Although several small cysteine-rich(SCR)secretory proteins,conser...A number of plant pathogenic species of Phytophthora are known to produce different classes of secretory proteins during interactions with their hosts.Although several small cysteine-rich(SCR)secretory proteins,conserved in oomycete pathogens,have been identified in Phytophthora,their specific involvement in these interactions remains unknown.In this study,an SCR effector encoded by Pn SCR82 in P.nicotianae was identified and shown to have similarities to P.cactorum phytotoxic protein,Pc F(Phytophthora cactorum Fragaria).Agroinfection with potato virus X vector,Pn SCR82,was capable of inducing plant hypersensitive cell death in Nicotiana benthamiana and Solanum lycopersicum.Real-time PCR results indicated that transiently expressed Pn SCR82 in N.benthamiana leaves activated the jasmonate,salicylic acid and ethylene signaling pathways.Transient expression of Pn SCR82 enhanced plant resisitance to P.capsici.In summary,our results demonstrated that P.nicotianae Pn SCR82 elicits defensive responses in N.benthamiana and may potentially play a significant role in future crop protection programs.展开更多
Environmental threats often trigger innate defensive responses in mammals.However,the gradual development of functional properties of these responses during the postnatal development stage remains unclear.Here,we repo...Environmental threats often trigger innate defensive responses in mammals.However,the gradual development of functional properties of these responses during the postnatal development stage remains unclear.Here,we report that looming stimulation in mice evoked fight behavior commencing at P14-16 and had fully developed by P20-24.The visual-evoked innate defensive response was not significantly altered by sensory deprivation at an early postnatal stage.Furthermore,the percentages of wide-field and horizontal cells in the superior colliculus were notably elevated at P20-24.Our findings define a developmental time window for the formation of the visual innate defense response during the early postnatal period and_provide important insight into the underlying mechanism.展开更多
Due to the hidden nature of roots in the soils, it is more challenging to investigate their resistance traits and defense responses as compared to those of the aerial organs. At the same time, it is self-evident that ...Due to the hidden nature of roots in the soils, it is more challenging to investigate their resistance traits and defense responses as compared to those of the aerial organs. At the same time, it is self-evident that root health is fundamental to a plant’s entire life and productivity. It is also easily conceivable that root function, physiology, morphology, and architecture are constantly impacted by the complex soil environment including both biotic and abiotic factors. This report summarizes and updates the challenges and progress in evaluating resistance responses of apple root to infection from a necrotrophic oomycete pathogen, Pythium ultimum. Several obstacles impede the progress of investigating apple root resistance traits including the difficulties of direct and real-time evaluation and the lack of a continuous supply of apple plants for repeated infection assays. Systematic and detailed analyses were made possible by implementing a micropropagation procedure for continuously generating uniform apple plants for repeated infection assays. As a result, an elite panel of apple rootstock germplasm with distinct resistance levels was identified. These apple rootstock genotypes with well-defined resistance levels are the much-needed plant materials for subsequent genomics and transgenics analyses to define the functional roles of specific candidate genes. Careful microscopic examination revealed contrasting necrosis progression patterns between resistant and susceptible genotypes, which shed light on the potential mechanisms underlying resistance traits. Our continuing research will provide a clearer view regarding the genetic elements regulating resistance traits in apple roots to P. ultimum infection.展开更多
Anoplophora glabripennis is one of the most devastating wood-boring beetles that attacks poplars.However,one poplar species,Populus deltoides,has strong resistance to Anoplophora glabripennis infestation,the underlyin...Anoplophora glabripennis is one of the most devastating wood-boring beetles that attacks poplars.However,one poplar species,Populus deltoides,has strong resistance to Anoplophora glabripennis infestation,the underlying defense mechanisms against Anoplophora glabripennis are poorly understood.Secondary metabolites play a crucial role in plants to combat biological stress.Here,based on transcriptome and metabolome,we demonstrated that the mechanisms for responses to mechanical damage and insect infestation were different.The degree of reactions to adult groove production,larval incubation,and larval frass production was not identical.In addition,the potential genes with insect resistance activity were identified.Predominant differentially expressed genes(DEGs)found in the phloem of Populus deltoides include anthocyanidin 3-O-glucosyltransferase5(PdUGT72E),peroxidase 73(PdPod73),peroxidase A2(PdPodA2)and macrophage migration inhibitory factor(PdMIF)responded to stress caused by Anoplophora glabripennis,which further resulted in activation of the plant defense system against insects via changes in regulation of metabolic pathways,such as tyrosine metabolism pathway,phenylpropanoid biosynthesis pathway and flavonoid biosynthesis pathway.Therefore,this work has laid a foundation for further unraveling the mechanisms involved in this interaction.展开更多
The defense mechanisms induced in wild Chinese pine(Pinus tabuliformis)in response to herbivores are not well characterized,especially in the field.To address this knowledge gap,we established a biological model syste...The defense mechanisms induced in wild Chinese pine(Pinus tabuliformis)in response to herbivores are not well characterized,especially in the field.To address this knowledge gap,we established a biological model system to evaluate proteome variations in pine needles after feeding by the Chinese pine caterpillar(Dendrolimus tabulaeformis),a major natural enemy and dominant herbivore.Quantitative tandem mass tag(TMT)proteomics and bioinformatics were utilized to systematically identify differentially abundant proteins implicated in the induced defense response of Chinese pine.We validated key protein changes using parallel reaction monitoring(PRM)technology.Pathway analysis revealed that the induced defenses involved phenylpropanoid,coumarin,and flavonoid biosynthesis,among other processes.To elucidate the regulatory patterns underlying pine resistance,we determined the activities of defense enzymes and levels of physiological and biochemical compounds.In addition,the expression of upstream genes for key proteins was validated by qRT-PCR.Our results provide new molecular insights into the induced defense mechanisms in Chinese pine against this caterpillar in the field.A better understanding of these defense strategies will inform efforts to breed more-resistant pine varieties.展开更多
Viruses are significant pathogens causing severe plant infections and crop losses globally.The resistance mechanisms of rice to viral diseases,particularly Southern rice black-streaked dwarf virus(SRBSDV),remain poorl...Viruses are significant pathogens causing severe plant infections and crop losses globally.The resistance mechanisms of rice to viral diseases,particularly Southern rice black-streaked dwarf virus(SRBSDV),remain poorly understood.In this study,we assessed SRBSDV susceptibility in 20 Xian/indica(XI)and 20 Geng/japonica(GJ)rice varieties.XI-1B accessions in the Xian subgroup displayed higher resistance than GJ accessions.Comparative transcriptome analysis revealed changes in processes like oxidoreductase activity,jasmonic acid(JA)metabolism,and stress response.JA sensitivity assays further linked antiviral defense to the JA pathway.These findings highlight a JA-mediated resistance mechanism in rice and offer insights for breeding SRBSDV-resistant varieties.展开更多
Rice blast disease caused by Magnaporthe oryzae poses a serious threat to rice security worldwide.This filamentous pathogen modulates rice defense responses by secreting effectors to facilitate infection.The phytohorm...Rice blast disease caused by Magnaporthe oryzae poses a serious threat to rice security worldwide.This filamentous pathogen modulates rice defense responses by secreting effectors to facilitate infection.The phytohormone jasmonic acid(JA)plays crucial roles in the response to rice blast fungus.However,how M.oryzae disrupts JA-mediated resistance in rice is not well understood.In this study,we identify a new effector,a chloroplast-targeting protein(MoCHT1),from M.oryzae.Knocking out MoCHT1 decreases virulence,whereas heterologous expression of MoCHT1 in rice compromises disease resistance.MoCHT1 interacts with a rice LESION AND LAMINA BENDING(OsLLB)protein,a negative regulator of JA biosynthesis in the chloroplast.Loss-of-function of Os LLB leads to increased JA accumulation,thereby improving resistance to rice blast.The interaction between MoCHT1 and OsLLB results in the inhibition of OsLLB degradation,consequently reducing JA accumulation,thereby impairing JA content and decreasing plant disease resistance.Overall,this study reveals the molecular mechanism by which M.oryzae utilizes MoCHT1 to subvert rice JA signaling,broadening our understanding of how pathogens circumvent host immune responses by manipulating plant defense hormone biosynthesis.展开更多
Reactive oxygen species(ROSs),including the superoxide anion radical(O_(2)·−)and hydrogen peroxide(H_(2)O_(2)),trigger plant responses to both biotic and abiotic stress(Mittler et al.,2022).Respiratory burst oxid...Reactive oxygen species(ROSs),including the superoxide anion radical(O_(2)·−)and hydrogen peroxide(H_(2)O_(2)),trigger plant responses to both biotic and abiotic stress(Mittler et al.,2022).Respiratory burst oxidase homolog(RBOH),a plant homolog of NADPH oxidase(NOX),converts O_(2) to O_(2)·−in the apoplast,using NADPH as the substrate(Figure 1;Torres,2010).ROS burst during defense response is regulated by the transcriptional and post-translational control of RBOH(Adachi et al.,2015).展开更多
WRKY transcription factors have many regulatory roles we isolated a rice WRKY gene （OsWRKY31） that is induced in response to biotic and abiotic stresses. In this study, by the rice blast fungus Magnaporthe grisea an...WRKY transcription factors have many regulatory roles we isolated a rice WRKY gene （OsWRKY31） that is induced in response to biotic and abiotic stresses. In this study, by the rice blast fungus Magnaporthe grisea and auxin. This gene encodes a polypeptide of 211 amino-acid residues and belongs to a subgroup of the rice WRKY gene family that probably originated after the divergence of monocot and dicot plants. OsWRKY31 was found to be localized to the nucleus of onion epidermis cells to transiently express OsWRKY31-eGFP fusion protein. Analysis of OsWRKY31 and its mutants fused with a Gal4 DNA-binding domain indicated that OsWRKY31 has transactivation activity in yeast. Overexpression of the OsWRKY31 gene was found to enhance resistance against infection with M. grisea, and the transgenic lines exhibited reduced lateral root formation and elongation compared with wild-type and RNAi plants. The lines with overexpression showed constitutive expression of many defense-related genes, such as PBZI and OsSci2, as well as early auxin-response genes, such as OslAA4 and OsCrll genes. Furthermore, the plants with overexpression were less sensitive to exogenously supplied IBA, NAA and 2,4-1） at high concentrations, suggesting that overexpression of the OsWRKY31 gene might alter the auxin response or transport. These results also suggest that OsWRKY31 might be a common component in the signal transduction pathways of the auxin response and the defense response in rice.展开更多
WRKY family proteins are a class of plant specific transcription factors that involve in many stress response pathways. It has been shown that one Arabidopsis WRKY protein, AtWRKY29/22, is activated by MAP kinase sign...WRKY family proteins are a class of plant specific transcription factors that involve in many stress response pathways. It has been shown that one Arabidopsis WRKY protein, AtWRKY29/22, is activated by MAP kinase signaling cascade and confers resistance to both bacterial and fungal pathogens. However, little is known about the biological roles of WRKY proteins in rice. In this study, we investigated the expression patterns of rice AtWRKY29/22 homolog, OsWRKY03, under different conditions, and also its possible role involved in plant defense. Our results showed that OsWRKY03 was up-regulated by several defense signaling molecules or different treatments. Further analysis revealed that the expression of OsWRKY03 was light dependent. Transcriptional activation activity of OsWRKY03 was also demonstrated by yeast functional assay. Transient expression of OsWRKY03-GFP fusion protein in onion epidermis cells showed that OsWRKY03 was a nuclear localized protein. OsNPR1 as well as several other pathogenesis-related genes, such as OsPRlb, phenylalanine ammonia-lyase （ZB8） and peroxidase （POX22.3）, were induced in OsWRKYO3-overexpressing transgenic plants. These results indicated that OsWRKY03 is located upstream of OsNPR 1 as a transcriptional activator in salicylic acid （SA）-dependent or jasmonic acid （JA）-dependent defense signaling cascades.展开更多
Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glyc...Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glycosylation, and ubiquitination, have been reported. Among them, ubiquitination distinguishes itself from others in that most of the ubiquitinated proteins are targeted to the 26S proteasome for degradation. The ubiquitin/26S proteasome system constitutes the major protein degradation pathway in the cell. In recent years, the importance of the ubiquitination machinery in the control of numerous eukaryotic cellular functions has been increasingly appreciated. Increasing number of E3 ubiquitin ligases and their substrates, including a variety of essential cellular regulators have been identified. Studies in the past several years have revealed that the ubiquitination system is important for a broad range of plant developmental processes and responses to abiotic and biotic stresses. This review discusses recent advances in the functional analysis of ubiquitination-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.展开更多
Jasmonic acid （JA） is a fatty acid-derived signaling molecule that regulates a broad range of plant defense responses against herbivores and some microbial pathogens. Molecular genetic studies have established that ...Jasmonic acid （JA） is a fatty acid-derived signaling molecule that regulates a broad range of plant defense responses against herbivores and some microbial pathogens. Molecular genetic studies have established that JA also performs a critical role in several aspects of plant development. Here, we describe the characterization of the Arabidopsis mutantjasmonic acid-hypersensitivel-1 （jah1-1）, which is defective in several aspects of JA responses. Although the mutant exhibits increased sensitivity to JA in root growth inhibition, it shows decreased expression of JA-inducible defense genes and reduced resistance to the necrotrophic fungus Botrytis cinerea. Gene cloning studies indicate that these defects are caused by a mutation in the cytochrome P450 protein CYP82C2. We provide evidence showing that the compromised resistance of thejah1-1 mutant to B. cinerea is accompanied by decreased expression of JA-induced defense genes and reduced accumulation of JA-induced indole glucosinolates （IGs）. Conversely, the enhanced resistance to B. cinerea in CYP82C2-overexpressing plants is accompanied by increased expression of JA-induced defense genes and elevated levels of JA-induced IGs. We demonstrate that CYP82C2 affects JA-induced accumulation of the IG biosynthetic precursor tryptophan （Trp）, but not the JA-induced IAA or pathogen-induced camalexin. Together, our results support a hypothesis that CYP82C2 may act in the metabolism of Trp-derived secondary metabolites under conditions in which JA levels are elevated. Thejah1-1 mutant should thus be important in future studies toward understanding the mechanisms underlying the complexity of JA-mediated differential responses, which are important for plants to adapt their growth to the ever-changing environments.展开更多
Triticum aestivum L. cv. Guizi 1(GZ1) is a drought-tolerant local purple wheat cultivar. It is not clear how purple wheat resists drought stress, but it could be related to anthocyanin biosynthesis. In this study, tra...Triticum aestivum L. cv. Guizi 1(GZ1) is a drought-tolerant local purple wheat cultivar. It is not clear how purple wheat resists drought stress, but it could be related to anthocyanin biosynthesis. In this study, transcriptome data from droughttreated samples and controls were compared. Drought slightly reduced the anthocyanin, protein and starch contents of GZ1 grains and significantly reduced the grain weight. Under drought stress, 16 682 transcripts were reduced, 27 766 differentially expressed genes(DEGs) were identified, and 379 DEGs, including DREBs, were related to defense response. The defense-response genes included response to water deprivation, reactive oxygen, bacteria, fungi, etc. Most of the structural and regulatory genes in anthocyanin biosynthesis were downregulated, with only Ta DFR, Ta OMT, Ta5,3GT, and Ta MYB-4 B1 being upregulated. Ta CHS, Ta F3H, TaCHI, Ta4CL, and TaF3’H are involved in responses to UV, hormones, and stimulus. Ta CHS-2D1, Ta DFR-2D2, Ta DFR-7D, TaOMT-5A, Ta5,3 GT-1B1, Ta5,3GT-3A, and Ta5,3GT-7B1 connect anthocyanin biosynthesis with other pathways, and their interacting proteins are involved in primary metabolism, genetic regulation, growth and development, and defense responses. There is further speculation about the defense-responsive network in purple wheat. The results indicated that biotic and abiotic stress-responsive genes were stimulated to resist drought stress in purple wheat GZ1, and anthocyanin biosynthesis also participated in the drought defense response through several structural genes.展开更多
基金supported by the National Key Research and Development Program of China(2022YFD2101101)the Earmarked Fund for CARS-19+2 种基金the National Natural Science Foundation of China(32402634)the Modern Agricultural(Tea)Industry Technology System of Fujian Province,China(2025 No.593)the Special Fund for Science and Technology Innovation of Fujian Zhang Tianfu Tea Development Foundation,China(FJZTF01)。
文摘Understanding the molecular responses of tea leaves to mechanical stress is crucial for elucidating the mechanisms of post-harvest quality formation during oolong tea processing.This study employed an integrated multi-omics strategy to characterize the changes and interactions among metabolomic(MB),transcriptomic(TX),and proteomic(PT)profiles in mechanically stressed tea leaves.Mechanical stress initially activated damage-associated molecular patterns(DAMPs),including Ca^(2+)signaling,jasmonic acid signaling,and glutathione metabolism pathways.These processes subsequently induced quality-related metabolic pathways(QRMPs),particularly α-linolenic acid and phenylalanine metabolism.Upregulated expression of LOX,ADH1,and PAR genes,together with the increased abundance of their encoded proteins,respectively promoted the accumulation of jasmine lactone,benzyl alcohol,and 2-phenylethanol.These findings indicate that mechanical stress influences the metabolite biosynthesis in tea leaves through coordinated molecular responses.This study provides new insights into the molecular mechanisms underlying tea leaf responses to mechanical stress and a foundation for future investigations into how early molecular events may contribute to post-harvest metabolic changes during oolong tea processing.
文摘Animals promote their survival by avoiding rapidly approaching objects that indicate threats.It is believed that looming cues are detected by retinal ganglion cells(RGCs)that project to the superior colliculus(SC).However,the exact type of RGC that transmits looming-related signals remains unclear.Here we identify a specific transient type of RGCs that controls mouse looming-evoked defensive response by sending axonal collaterals to the dorsal raphe nucleus(DRN)and SC.Looming signals transmitted by DRN-projecting RGCs activate DRN GABA neurons and in turn inhibit serotonin neurons.Moreover,optogenetically stimulating serotonin neurons reduces looming-evoked defensive behaviors.Thus,a dedicated population of RGCs detects rapidly approaching visual threats and their input to the DRN controls a serotonergic self-gating mechanism that regulates innate defensive responses.Our study provides new insights into how DRN and SC work in concert to extract and translate visual threats into defensive behavioral responses.
基金Acknowledgments We are grateful to Dr Xinnian Dong （Duke University, Durham, NC, USA） for critical reading of the manuscript and valuable suggestions. We thank Dr Jianmin Zhou （National Institute of Biological Sciences, Beijing, China） for providing the fungus strain Botrytis cinerea, Dr Salome Prat （Institut de Biologia Molecular de Barcelona, Barcelona, Spain） for providing homozygous atmyc2-2 （T-DNA insertion line SALK_083483） seeds and Dr Daoxin Xie （Tsinghua University, Beijing, China） for providing the coil-I seeds. This work was supported by grants from The National Natural Science Foundation of China （30530440）, The Ministry of Science and Technology of China （2006CB 102004, 2006AA10A 116）, and The Chinese Academy of Sciences （KSCX2-YW-N-045）.
文摘Jasmonic acid （JA） is an important phytohormone that regulates plant defense responses against herbivore attack, pathogen infection and mechanical wounding. In this report, we provided biochemical and genetic evidence to show that the Arabidopsis thaliana NAC family proteins ANAC019 and ANAC055 might function as transcription activators to regulate JA-induced expression of defense genes. The role of the two NAC genes in JA signaling was examined with the anacO19 anac055 double mutant and with transgenic plants overexpressing ANACO19 or ANAC055. The anacO19 anac055 double mutant plants showed attenuated JA-induced VEGETATIVE STORAGE PROTEIN1 （VSP1） and LIPOXYGENASE2 （LOX2） expression, whereas transgenic plants overexpressing the two NAC genes showed enhanced JA-induced VSP1 and LOX2 expression. That the JA-induced expression of the two NAC genes depends on the function of COIl and AtMYC2, together with the finding that overexpression of ANACO19 partially rescued the JA-related phenotype of the atmyc2-2 mutant, has led us to a hypothesis that the two NAC proteins act downstream of AtMYC2 to regulate JA-signaled defense responses. Further evidence to substantiate this idea comes from the observation that the response of the anacO19 anac055 double mutant to a necrotrophic fungus showed high similarity to that of the atmyc2-2 mutant.
基金supported by the National Science Foundation of China(Grant No.39930010)a NSFC Fund for Creative Research Groups(Grant No.30421002)to Wei Hua WU
文摘Although there were reports suggesting the involvement of endogenous cAMP in plant defense signaling cascades, there is no direct evidence supporting this notion yet and the detailed mechanism is unclear. In the present study, we have used pathogenic fungi Verticillium dahliae and Arabidopsis plants as a model system of plant-microb interaction to demonstrate the function of endogenous cAMP in Arabidopsis defense responses. Both V. dahliae inoculation and Verticillium toxins injection induced typical “wilt” symptoms in Arabidopsis seedlings. When either 8-Br-AMP (a membrane permeable cAMP analogue) or salicylic acid (SA) was applied to Arabidopsis, the plants became resistant to V. dahliae toxins. However, addition of 8-Br-AMP did not increase the resistance of Arabidopsis transgenic plants deficient in SA to the toxins, suggesting that cAMP might act upstream of SA in plant defense signaling pathway. Indeed, 8-Br-cAMP and forskolin, an activator of adenylyl cyclase, significantly stimulated the endogenous SA level in plants, whereas DDA, an inhibitor of adenylyl cyclase dramatically reduced toxin-induced SA increase. Both the endog- enous cAMP and SA increased significantly in Arabidopsis seedlings treated with toxins. Furthermore, transcription level of pathogenesis-related protein 1 gene (PR1) was strongly induced by both 8-Br-cAMP and the toxin treatment. Taken together, our data demonstrate that endogenous cAMP is involved in plant defense responses against Verticillium- secreted toxins by regulating the production of the known signal SA in plant defense pathway.
文摘Phenotypical, cytological and molecular responses of rice to the fungus Magnaporthe grisea were studied using rice cultivars and lesion mimic plants. The cultivar Katy was susceptible to several virulent M. grisea isolates, and a Sekiguchi like-lesion mimic mutant of Katy （LmmKaty） showed enhanced resistance to these isolates. Lesion mimic phenotype of LmmKaty was rapidly induced by virulent M. grisea isolates or by avirulent ones only at high levels of inoculum. Autofluorescence （a sign of an active defense response） was visible under ultraviolet light 24 h after localized inoculation in the incompatible interaction, whereas, not evident in the compatible interaction. Autofluorescence was also observed in LmmKaty 20 h after pathogen inoculation, indicating that rapid cell death is a mechanism of LmmKaty to restrict pathogen invasion. Rapid accumulations of defense related （DR） gene transcripts, phenylalanine ammonia lyase and β-glucanase, were observed beginning at 6 h and were obvious at 16 h and 24 h after inoculation in an incompatible interaction. Rapid transcript accumulations of PR-1 and chitinase had occurred by 24 h after inoculation in an incompatible interaction. Accumulations of these transcripts were delayed in the compatible interaction. These results indicate that host active defense responses occur 24 h after pathogen inoculation and that LmmKaty exhibits enhanced resistance to M. grisea. It is suggested that the autofluorescence and expression of the DR genes after heavy inoculation are important cytological and molecular markers respectively for early determination of the host response to M. grisea in the rice blast system.
基金financially supported by grants from the National Key Research and Development Program of China(2016YFD0100601)the National Natural Science Foundation of China(31701057 and 31672013)+5 种基金the Natural Science Foundation of Jiangsu Province,China(BK20170487)the Fok Ying Tung Education Foundation,China(151026)the China Postdoctoral Science Foundation(2017M620227)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(19KJD210001)2018 Annual Key Project of Scientific Research in Yangzhou Polytechnic College,China(2018ZR07)。
文摘The soil-borne necrotrophic fungus Rhizoctonia solani is one of destructive fungi causing severe yield losses in various important crops. However, the host defense mechanisms against the invasion of this pathogen are poorly understood. In this study, we employed an i TRAQ-based quantitative proteomic approach to investigate host proteins responsive to R. solani using the resistant rice cultivar YSBR1. As a whole, we identified 319 differentially accumulated proteins(DAPs) after inoculation of rice plants with R. solani. Functional categorization analysis indicates that these DAPs cover a broad range of functions. Notably, a substantial portion of the DAPs are involved in cell redox homeostasis, carbohydrate metabolism, and phenylpropanoid biosynthesis, or belong to pathogenesis-related proteins, indicating that these processes/proteins play important roles in host defense against R. solani. Interestingly, all of the DAPs involved in photosynthesis and chlorophyll biosynthetic processes, and part of the DAPs involved in phenylpropanoid biosynthesis, show reduced accumulation after R. solani infection, suggesting that R. solani probably inhibits host photosynthetic system and phenylpropanoid biosynthesis to facilitate infection and colonization. In conclusion, our results provide both valuable resources and new insights into the molecular mechanisms underlying rice and R. solani interaction.
基金supported by grants from the National Key R&D Program of China(2017YFE0103400)the National Nature Science Foundation of China(81470628).
文摘Parvalbumin-positive retinal ganglion cells(PV+RGCs)are an essential subset of RGCs found in various species.However,their role in transmitting visual information remains unclear.Here,we characterized PV+RGCs in the retina and explored the functions of the PV+RGC-mediated visual pathway.By applying multiple viral tracing strategies,we investigated the downstream of PV+RGCs across the whole brain.Interestingly,we found that the PV+RGCs provided direct monosynaptic input to PV+excitatory neurons in the superficial layers of the superior colliculus(SC).Ablation or suppression of SC-projecting PV+RGCs abolished or severely impaired the flight response to looming visual stimuli in mice without affecting visual acuity.Furthermore,using transcriptome expression profiling of individual cells and immunofluorescence colocalization for RGCs,we found that PV+RGCs are predominant glutamatergic neurons.Thus,our findings indicate the critical role of PV+RGCs in an innate defensive response and suggest a non-canonical subcortical visual pathway from excitatory PV+RGCs to PV+SC neurons that regulates looming visual stimuli.These results provide a potential target for intervening and treating diseases related to this circuit,such as schizophrenia and autism.
基金supported by the National Natural Science Foundation of China(31972218,31501590,and 31601615)the Program for Talents in Qingdao Agricultural University,China(6631114307)the Independent Innovation of Agricultural Sciences in Jiangsu Province,China(CX(18)3012)。
文摘A number of plant pathogenic species of Phytophthora are known to produce different classes of secretory proteins during interactions with their hosts.Although several small cysteine-rich(SCR)secretory proteins,conserved in oomycete pathogens,have been identified in Phytophthora,their specific involvement in these interactions remains unknown.In this study,an SCR effector encoded by Pn SCR82 in P.nicotianae was identified and shown to have similarities to P.cactorum phytotoxic protein,Pc F(Phytophthora cactorum Fragaria).Agroinfection with potato virus X vector,Pn SCR82,was capable of inducing plant hypersensitive cell death in Nicotiana benthamiana and Solanum lycopersicum.Real-time PCR results indicated that transiently expressed Pn SCR82 in N.benthamiana leaves activated the jasmonate,salicylic acid and ethylene signaling pathways.Transient expression of Pn SCR82 enhanced plant resisitance to P.capsici.In summary,our results demonstrated that P.nicotianae Pn SCR82 elicits defensive responses in N.benthamiana and may potentially play a significant role in future crop protection programs.
基金This work was supported by the National Natural Science Foundation of China(31930047,91732304 and 31630031)The Strategic Priority Research Program of the Chinese Academy of Science(XDB32030100)+9 种基金Guangdong Provincial Key Laboratory of Brain Connectome and Behavior(2017B030301017)the Natural,Science Foundationo Gfuangdong,Province(2018A030313439)a Shenzhen Government grant(JCYJ20170413164535041)Shenzhen Key Science and Technology Infrastructure Planning Project(ZDKJ20190204002)Key Laboratory of CAS(2019DP173024)The Ten Thousand Talents ProgramThe Guangdong Special Support ProgramChang Jiang Scholars ProgramIntermational PartnershipProgram of theChinese Academy of Sciences(172644KYS820170004)and the Key-Area Research and Development Program of Guangdong Province(2018B030331001).
文摘Environmental threats often trigger innate defensive responses in mammals.However,the gradual development of functional properties of these responses during the postnatal development stage remains unclear.Here,we report that looming stimulation in mice evoked fight behavior commencing at P14-16 and had fully developed by P20-24.The visual-evoked innate defensive response was not significantly altered by sensory deprivation at an early postnatal stage.Furthermore,the percentages of wide-field and horizontal cells in the superior colliculus were notably elevated at P20-24.Our findings define a developmental time window for the formation of the visual innate defense response during the early postnatal period and_provide important insight into the underlying mechanism.
文摘Due to the hidden nature of roots in the soils, it is more challenging to investigate their resistance traits and defense responses as compared to those of the aerial organs. At the same time, it is self-evident that root health is fundamental to a plant’s entire life and productivity. It is also easily conceivable that root function, physiology, morphology, and architecture are constantly impacted by the complex soil environment including both biotic and abiotic factors. This report summarizes and updates the challenges and progress in evaluating resistance responses of apple root to infection from a necrotrophic oomycete pathogen, Pythium ultimum. Several obstacles impede the progress of investigating apple root resistance traits including the difficulties of direct and real-time evaluation and the lack of a continuous supply of apple plants for repeated infection assays. Systematic and detailed analyses were made possible by implementing a micropropagation procedure for continuously generating uniform apple plants for repeated infection assays. As a result, an elite panel of apple rootstock germplasm with distinct resistance levels was identified. These apple rootstock genotypes with well-defined resistance levels are the much-needed plant materials for subsequent genomics and transgenics analyses to define the functional roles of specific candidate genes. Careful microscopic examination revealed contrasting necrosis progression patterns between resistant and susceptible genotypes, which shed light on the potential mechanisms underlying resistance traits. Our continuing research will provide a clearer view regarding the genetic elements regulating resistance traits in apple roots to P. ultimum infection.
基金supported by the National Natural Science Foundation of China(Nos.32271891 and 32171798).
文摘Anoplophora glabripennis is one of the most devastating wood-boring beetles that attacks poplars.However,one poplar species,Populus deltoides,has strong resistance to Anoplophora glabripennis infestation,the underlying defense mechanisms against Anoplophora glabripennis are poorly understood.Secondary metabolites play a crucial role in plants to combat biological stress.Here,based on transcriptome and metabolome,we demonstrated that the mechanisms for responses to mechanical damage and insect infestation were different.The degree of reactions to adult groove production,larval incubation,and larval frass production was not identical.In addition,the potential genes with insect resistance activity were identified.Predominant differentially expressed genes(DEGs)found in the phloem of Populus deltoides include anthocyanidin 3-O-glucosyltransferase5(PdUGT72E),peroxidase 73(PdPod73),peroxidase A2(PdPodA2)and macrophage migration inhibitory factor(PdMIF)responded to stress caused by Anoplophora glabripennis,which further resulted in activation of the plant defense system against insects via changes in regulation of metabolic pathways,such as tyrosine metabolism pathway,phenylpropanoid biosynthesis pathway and flavonoid biosynthesis pathway.Therefore,this work has laid a foundation for further unraveling the mechanisms involved in this interaction.
基金supported by the Science and Technology Development Program of Hebei Agricultural University,the Research on Molecular Mechanisms of Population Differentiation and Adaptation of Forest Pests and Insects under Environmental Stress(grant No.:30771739)Forest Pests and Diseases(grant No.:1528003)the National Natural Science Foundation of China for the study of community regulatory mechanisms of insect pest pandemics in larch plantation forests(Grant No.:32371882).
文摘The defense mechanisms induced in wild Chinese pine(Pinus tabuliformis)in response to herbivores are not well characterized,especially in the field.To address this knowledge gap,we established a biological model system to evaluate proteome variations in pine needles after feeding by the Chinese pine caterpillar(Dendrolimus tabulaeformis),a major natural enemy and dominant herbivore.Quantitative tandem mass tag(TMT)proteomics and bioinformatics were utilized to systematically identify differentially abundant proteins implicated in the induced defense response of Chinese pine.We validated key protein changes using parallel reaction monitoring(PRM)technology.Pathway analysis revealed that the induced defenses involved phenylpropanoid,coumarin,and flavonoid biosynthesis,among other processes.To elucidate the regulatory patterns underlying pine resistance,we determined the activities of defense enzymes and levels of physiological and biochemical compounds.In addition,the expression of upstream genes for key proteins was validated by qRT-PCR.Our results provide new molecular insights into the induced defense mechanisms in Chinese pine against this caterpillar in the field.A better understanding of these defense strategies will inform efforts to breed more-resistant pine varieties.
基金funded by the National Key Research and Development Plan of China(2023YFD1400300)National Natural Science Foundation of China(U23A6006,32270149,32272555)+1 种基金Zhejiang Provincial Natural Science Foundation(LZ22C140001)the Ningbo Major Research and Development Plan Project(2023Z124).
文摘Viruses are significant pathogens causing severe plant infections and crop losses globally.The resistance mechanisms of rice to viral diseases,particularly Southern rice black-streaked dwarf virus(SRBSDV),remain poorly understood.In this study,we assessed SRBSDV susceptibility in 20 Xian/indica(XI)and 20 Geng/japonica(GJ)rice varieties.XI-1B accessions in the Xian subgroup displayed higher resistance than GJ accessions.Comparative transcriptome analysis revealed changes in processes like oxidoreductase activity,jasmonic acid(JA)metabolism,and stress response.JA sensitivity assays further linked antiviral defense to the JA pathway.These findings highlight a JA-mediated resistance mechanism in rice and offer insights for breeding SRBSDV-resistant varieties.
基金funded by the Biological Breeding-National Science and Technology Major Projects(2023ZD04070)the National Natural Science Foundation of China(31970284,31900385)+1 种基金the Fujian Provincial Science and Technology Key Project(2022NZ030014)the Natural Science Foundation of Fujian Province,China(2023J01483,2022J01616)。
文摘Rice blast disease caused by Magnaporthe oryzae poses a serious threat to rice security worldwide.This filamentous pathogen modulates rice defense responses by secreting effectors to facilitate infection.The phytohormone jasmonic acid(JA)plays crucial roles in the response to rice blast fungus.However,how M.oryzae disrupts JA-mediated resistance in rice is not well understood.In this study,we identify a new effector,a chloroplast-targeting protein(MoCHT1),from M.oryzae.Knocking out MoCHT1 decreases virulence,whereas heterologous expression of MoCHT1 in rice compromises disease resistance.MoCHT1 interacts with a rice LESION AND LAMINA BENDING(OsLLB)protein,a negative regulator of JA biosynthesis in the chloroplast.Loss-of-function of Os LLB leads to increased JA accumulation,thereby improving resistance to rice blast.The interaction between MoCHT1 and OsLLB results in the inhibition of OsLLB degradation,consequently reducing JA accumulation,thereby impairing JA content and decreasing plant disease resistance.Overall,this study reveals the molecular mechanism by which M.oryzae utilizes MoCHT1 to subvert rice JA signaling,broadening our understanding of how pathogens circumvent host immune responses by manipulating plant defense hormone biosynthesis.
基金supported by the JSPS KAKENHI(grant no.25K01984)to T.Y.
文摘Reactive oxygen species(ROSs),including the superoxide anion radical(O_(2)·−)and hydrogen peroxide(H_(2)O_(2)),trigger plant responses to both biotic and abiotic stress(Mittler et al.,2022).Respiratory burst oxidase homolog(RBOH),a plant homolog of NADPH oxidase(NOX),converts O_(2) to O_(2)·−in the apoplast,using NADPH as the substrate(Figure 1;Torres,2010).ROS burst during defense response is regulated by the transcriptional and post-translational control of RBOH(Adachi et al.,2015).
文摘WRKY transcription factors have many regulatory roles we isolated a rice WRKY gene （OsWRKY31） that is induced in response to biotic and abiotic stresses. In this study, by the rice blast fungus Magnaporthe grisea and auxin. This gene encodes a polypeptide of 211 amino-acid residues and belongs to a subgroup of the rice WRKY gene family that probably originated after the divergence of monocot and dicot plants. OsWRKY31 was found to be localized to the nucleus of onion epidermis cells to transiently express OsWRKY31-eGFP fusion protein. Analysis of OsWRKY31 and its mutants fused with a Gal4 DNA-binding domain indicated that OsWRKY31 has transactivation activity in yeast. Overexpression of the OsWRKY31 gene was found to enhance resistance against infection with M. grisea, and the transgenic lines exhibited reduced lateral root formation and elongation compared with wild-type and RNAi plants. The lines with overexpression showed constitutive expression of many defense-related genes, such as PBZI and OsSci2, as well as early auxin-response genes, such as OslAA4 and OsCrll genes. Furthermore, the plants with overexpression were less sensitive to exogenously supplied IBA, NAA and 2,4-1） at high concentrations, suggesting that overexpression of the OsWRKY31 gene might alter the auxin response or transport. These results also suggest that OsWRKY31 might be a common component in the signal transduction pathways of the auxin response and the defense response in rice.
文摘WRKY family proteins are a class of plant specific transcription factors that involve in many stress response pathways. It has been shown that one Arabidopsis WRKY protein, AtWRKY29/22, is activated by MAP kinase signaling cascade and confers resistance to both bacterial and fungal pathogens. However, little is known about the biological roles of WRKY proteins in rice. In this study, we investigated the expression patterns of rice AtWRKY29/22 homolog, OsWRKY03, under different conditions, and also its possible role involved in plant defense. Our results showed that OsWRKY03 was up-regulated by several defense signaling molecules or different treatments. Further analysis revealed that the expression of OsWRKY03 was light dependent. Transcriptional activation activity of OsWRKY03 was also demonstrated by yeast functional assay. Transient expression of OsWRKY03-GFP fusion protein in onion epidermis cells showed that OsWRKY03 was a nuclear localized protein. OsNPR1 as well as several other pathogenesis-related genes, such as OsPRlb, phenylalanine ammonia-lyase （ZB8） and peroxidase （POX22.3）, were induced in OsWRKYO3-overexpressing transgenic plants. These results indicated that OsWRKY03 is located upstream of OsNPR 1 as a transcriptional activator in salicylic acid （SA）-dependent or jasmonic acid （JA）-dependent defense signaling cascades.
文摘Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glycosylation, and ubiquitination, have been reported. Among them, ubiquitination distinguishes itself from others in that most of the ubiquitinated proteins are targeted to the 26S proteasome for degradation. The ubiquitin/26S proteasome system constitutes the major protein degradation pathway in the cell. In recent years, the importance of the ubiquitination machinery in the control of numerous eukaryotic cellular functions has been increasingly appreciated. Increasing number of E3 ubiquitin ligases and their substrates, including a variety of essential cellular regulators have been identified. Studies in the past several years have revealed that the ubiquitination system is important for a broad range of plant developmental processes and responses to abiotic and biotic stresses. This review discusses recent advances in the functional analysis of ubiquitination-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.
基金We gratefully acknowledge Dr Jianru Zuo （Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, China） for providing T-DNA mutagenized population of Arabidopsis, Dr Salome Prat （Institut de Biologia Molecular de Barcelona, Spain） for providing homozygous atmyc2-2 mutant （T-DNA insertion line SALK_083483） seeds and Dr Jane Glazebrook for assisting with camalexin measurements. This work was supported by grants from the Chinese Academy of Sciences （KSCX2- YW-N-045, KSCX2-YW-N-015）, the Ministry of Agriculture of China （2008ZX08009-003-001） and the Ministry of Science and Technology of China （2007CB948201, 2006AA10A116）. Work in the laboratory of Jerry D Cohen was supported by grants from the US National Science Foundation （MCB-0725149 and DBI- PGRP-0606666） and the USDA, National Research Initiative （2005-35318-16197）.
文摘Jasmonic acid （JA） is a fatty acid-derived signaling molecule that regulates a broad range of plant defense responses against herbivores and some microbial pathogens. Molecular genetic studies have established that JA also performs a critical role in several aspects of plant development. Here, we describe the characterization of the Arabidopsis mutantjasmonic acid-hypersensitivel-1 （jah1-1）, which is defective in several aspects of JA responses. Although the mutant exhibits increased sensitivity to JA in root growth inhibition, it shows decreased expression of JA-inducible defense genes and reduced resistance to the necrotrophic fungus Botrytis cinerea. Gene cloning studies indicate that these defects are caused by a mutation in the cytochrome P450 protein CYP82C2. We provide evidence showing that the compromised resistance of thejah1-1 mutant to B. cinerea is accompanied by decreased expression of JA-induced defense genes and reduced accumulation of JA-induced indole glucosinolates （IGs）. Conversely, the enhanced resistance to B. cinerea in CYP82C2-overexpressing plants is accompanied by increased expression of JA-induced defense genes and elevated levels of JA-induced IGs. We demonstrate that CYP82C2 affects JA-induced accumulation of the IG biosynthetic precursor tryptophan （Trp）, but not the JA-induced IAA or pathogen-induced camalexin. Together, our results support a hypothesis that CYP82C2 may act in the metabolism of Trp-derived secondary metabolites under conditions in which JA levels are elevated. Thejah1-1 mutant should thus be important in future studies toward understanding the mechanisms underlying the complexity of JA-mediated differential responses, which are important for plants to adapt their growth to the ever-changing environments.
基金supported by the grants from the National Key R&D Program of China (2017YFD0100901-4 and 2016YFC0502604)the National Natural Science Foundation of China (31660390)+5 种基金the Major Special Project of Science and Technology Program in Guizhou, China (2017-5411-06 and 2017-5788)the Construction Project of State Engineering Technology Institute for Karst Desertification Control, China (2012FU125X13)the Innovation Talents Team Construction of Science and Technology in Guizhou, China (2016-5624)the Major Research Project of Innovation Group in Guizhou, China (2016-023)the Graduate Innovation Fund of Guizhou University, China (2017025)the Science and Technology Project in Guizhou, China (2019-4246)
文摘Triticum aestivum L. cv. Guizi 1(GZ1) is a drought-tolerant local purple wheat cultivar. It is not clear how purple wheat resists drought stress, but it could be related to anthocyanin biosynthesis. In this study, transcriptome data from droughttreated samples and controls were compared. Drought slightly reduced the anthocyanin, protein and starch contents of GZ1 grains and significantly reduced the grain weight. Under drought stress, 16 682 transcripts were reduced, 27 766 differentially expressed genes(DEGs) were identified, and 379 DEGs, including DREBs, were related to defense response. The defense-response genes included response to water deprivation, reactive oxygen, bacteria, fungi, etc. Most of the structural and regulatory genes in anthocyanin biosynthesis were downregulated, with only Ta DFR, Ta OMT, Ta5,3GT, and Ta MYB-4 B1 being upregulated. Ta CHS, Ta F3H, TaCHI, Ta4CL, and TaF3’H are involved in responses to UV, hormones, and stimulus. Ta CHS-2D1, Ta DFR-2D2, Ta DFR-7D, TaOMT-5A, Ta5,3 GT-1B1, Ta5,3GT-3A, and Ta5,3GT-7B1 connect anthocyanin biosynthesis with other pathways, and their interacting proteins are involved in primary metabolism, genetic regulation, growth and development, and defense responses. There is further speculation about the defense-responsive network in purple wheat. The results indicated that biotic and abiotic stress-responsive genes were stimulated to resist drought stress in purple wheat GZ1, and anthocyanin biosynthesis also participated in the drought defense response through several structural genes.
