Peanuts are important oilseed legume crops that are susceptible to contamination by Aspergillus flavus in soil,leading to serious economic losses.Previously,our research team developed the Aspergillus-Rihizobia coupli...Peanuts are important oilseed legume crops that are susceptible to contamination by Aspergillus flavus in soil,leading to serious economic losses.Previously,our research team developed the Aspergillus-Rihizobia coupling(ARC)microbial inoculants and found it can reduce A.flavus abundance in the soil and promote efficient nodulation in peanuts.However,the impact of ARC microbial inoculants on different resistant varieties of A.flavus remains unclear.In this study,we screened peanut varieties that were resistant and susceptible to A.flavus and evaluated their nodulation ability and growth performance after ARC microbial inoculants treatment in the field.The results demonstrated that the nodule number and nitrogenase activity of both varieties significantly increased after ARC microbial inoculants treatment,with the highly susceptible variety AH24 showing a greater increase.For photosynthetic parameters,both varieties also increased after ARC microbial inoculants treatment,but the increase was greater in the moderately resistant variety AH1 than in the highly susceptible variety AH24.Finally,we found that the yield and yield-related traits of the moderately resistant variety AH1 were better than those of the highly susceptible variety AH24.After ARC microbial inoculants treatment,the yield traits of both peanut varieties still increased significantly,but the degree of increase of the moderately resistant variety AH1 was smaller than that of the highly susceptible variety AH24.In addition,the abundance of A.flavus in the rhizosphere soil of the two varieties significantly decreased after ARC microbial inoculants treatment,with no significant difference between the varieties.These results indicated that ARC microbial inoculants exert differential effects on the nodulation and growth of different resistant peanut varieties and have a better effect on highly susceptible varieties.These results provide a solid theoretical basis for the efficient use of ARC microbial inoculants in the field of peanuts in the future.展开更多
In nature, plant extracts play a crucial role in defending plants against biotic and abiotic stressors. Moreover, the use of plant-based products, such as plant extracts, represents a promising alternative to syntheti...In nature, plant extracts play a crucial role in defending plants against biotic and abiotic stressors. Moreover, the use of plant-based products, such as plant extracts, represents a promising alternative to synthetic fungicides, which pose potential health risks to consumers. In this study, the antifungal activity of the essential oils (EOs) of Lippia multiflora, Eucalyptus camaldulensis and Ocimum americanum was evaluated against two strains of Aspergillus flavus via the agar dilution method. These two Aspergillus flavus fungi was isolated from Bamabra groundnut seeds. Lippia multiflora essential oil (EO) showed the best results compared with the other oils, with a minimum inhibitory concentration (MIC) of 9000 μg∙mL−1. The MIC for Eucalyptus camaldulensis and Ocimum americanum EOs was 10,800 μg∙mL−1. In view of their antifungal properties, these EOs could be used to develop a new, safe antifungal agent for food preservation.展开更多
In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different...In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different peanut varieties to the inoculation with A. flavus has not been investigated and might be useful for breed- ing resistant peanut cultivars. In this study, peanut varieties resistant or susceptible to aflatoxin accumulation caused by A. flavus were selected to compare the synthe- sis differences of the four main stilbenes （resveratrol, ε-viniferin, 6-viniferin and pterostilbene） and the activities of their resistant enzymes （PAL, POD, PPO）, and explore the relationship between stilbene synthesis and resistance to aflatoxin accu- mulation. The results indicated that the synthesis speed of stilbenes was related to the resistance to aflatoxin accumulation in peanuts seeds. The total content of the four stilbenes reached the highest value of 47.37 μg/g in the resistant cultivars （Qian huasheng 3） after inoculation by A. flavus （54 times of the control） on the 3nd day, while the total content of stilbenes in susceptible cultivars （Huayu 22） was 5.5 μg/g. The content of stilbenes and the activities of their resistant enzymes from the resistant cultivars were both higher than from the susceptible one. The four peanut varieties with relative higher stilbene contents and lower disease index and aflatoxin content were selected by using the stilbene content. Very significant negative corre- lation, with correlation coefficients （r） of -0.789, -0.851 and -0.850, was observed between the stilbene content with disease index, the content of aflatoxin B1 and the total content of aflatoxins, respectively. Therefore, the study suggested that the total content of stilbene compounds might serve as an important chemical index in peanut seeds after inoculation with A. flavus on the 3nd day, during screening and breeding of peanut varieties resistant to aflatoxin accumulation.展开更多
A new oxygenated tricyclic cyclopiazonic acid(CPA)alkaloid,asperorydine Q(1),along with seven known compounds,namely,asperorydines O(2)and J(3),speradine H(4),cyclopiamides A(5)and H(6),saadamysin(7),and pyrazinemetha...A new oxygenated tricyclic cyclopiazonic acid(CPA)alkaloid,asperorydine Q(1),along with seven known compounds,namely,asperorydines O(2)and J(3),speradine H(4),cyclopiamides A(5)and H(6),saadamysin(7),and pyrazinemethanol(8),were isolated from the coral-associated Aspergillus flavus GXIMD 02503.The structures were elucidated by physicochemical properties and comprehensive spectroscopic data analysis.Compounds 1−5 and 7−8 exhibited potent inhibition of lipopolysaccharide(LPS)-induced nuclear factor-κB(NF-κB)with the IC50 values ranging from 6.5 to 21.8μmol L^(−1).In addition,the most potent one,pyrazinemethanol(8),dose-dependently suppressed receptor activator of NF-κB ligand(RANKL)-induced osteoclast differentiation without obvious cytotoxicity in bone marrow macrophages cells(BMMCs),suggesting it is a promising lead compound for the treatment of osteolytic diseases.展开更多
Fungi produce a variety of microbial volatile organic compounds (MVOCs) during primary and secondary metabolism. The fungus, Aspergillus flavus, is a human, animal and plant pathogen which produces aflatoxin, one of t...Fungi produce a variety of microbial volatile organic compounds (MVOCs) during primary and secondary metabolism. The fungus, Aspergillus flavus, is a human, animal and plant pathogen which produces aflatoxin, one of the most carcinogenic substances known. In this study, MVOCs were analyzed using solid phase microextraction (SPME) combined with GCMS from two genetically different A. flavus strains, an aflatoxigenic strain, NRRL 3357, and a non-aflatoxigenic strain, NRRL 21882. A PDMS/CAR SPME fiber was used over 30 days to observe variations in MVOCs over time. The relative percentage of individual chemicals in several chemical classes (alcohols, aldehydes, esters, furans, hydrocarbons, ketones, and organic acids) was shown to change considerably during the varied fungal growth stages. This changing chemical profile reduces the likelihood of finding a single chemical that can be used consistently as a biomarker for fungal strain identification. In our study, discriminant analysis techniques were successfully conducted using all identified and quantified MVOCs enabling discrimination of the two A. flavus strains over the entire 30-day period. This study underscores the potential of using SPME GCMS coupled with multivariate analysis for fungi strain identification.展开更多
Maize （Zea mays L.）, one of main crops in the world, is easily susceptible to Aspergillusflavus （Link： fr） infection, resulting huge loses worldwide. Breeding for A. flavus resistance has been proved an efficient...Maize （Zea mays L.）, one of main crops in the world, is easily susceptible to Aspergillusflavus （Link： fr） infection, resulting huge loses worldwide. Breeding for A. flavus resistance has been proved an efficient way to solve the problem of aflatoxin contamination. Genetic analysis of the sources of resistance to A.flavus in maize is necessary for this purpose. The complete diallel crosses of 6 inbred lines with different resistance to A.flavus infection were implemented. Inoculation categorical data of each cross were analyzed with the additive-dominant and additive-dominant-epitasis genetic models. Results indicated some crosses fitted the 2 major genes with additive-dominant-epitasis genetic model. Others fitted the major gene and polygene mixed model. Moreover, the additive, dominant, and epitasis effects varied in crosses. The A.flavus resistance was controlled by both major gene and polygene.展开更多
To study the structure-antifungal activity of vanillin against Aspergillus flavus(A.flavus),the susceptibilities of A.flavus to vanillin and its isomers(o-vanillin,2-hydroxy-4-methoxybenzaldehyde(HMB),2-hydroxy-5-meth...To study the structure-antifungal activity of vanillin against Aspergillus flavus(A.flavus),the susceptibilities of A.flavus to vanillin and its isomers(o-vanillin,2-hydroxy-4-methoxybenzaldehyde(HMB),2-hydroxy-5-methoxybenzaldehyde)and the possible antifungal mechanisms have been investigated.All the four volatile aldehydes could inhibit the germination of spores,and the minimum inhibitory concentrations(MICs)of them were in this order:vanillin(200μg/mL),o-vanillin(100μg/mL),2-hydroxy-5-methoxybenzaldehyde(100μg/mL),HMB(70μg/mL).The minimum fungicidal concentrations(MFCs)of them were in this order:vanillin(240μg/mL),o-vanillin(160μg/mL),HMB(140μg/mL),2-hydroxy-5-methoxybenzaldehyde(140μg/mL).Spore size was arrested at 0 h with the treatment of the four volatile aldehydes.Effects of the four volatile aldehydes on the cell wall and cell membrane integrity of A flavus were observed by calcofluor white(CW)staining and propidium iodide(PI)staining.The results showed that HMB exerted the strongest antifungal and fungicidal effects on the growth of A.flavus.The four volatile aldehydes had little influence on cell wall integrity after 3-hour treatment,however,they could strongly damage the cell membrane integrity.All the four volatile aldehydes could effectively prevent the growth of A.flavus on peanut seeds.The antifungal mechanisms of the four volatile aldehydes provide theoretical foundations for their development of new antifungal agents.展开更多
In the process of the fermentation of steroid C11α-hydroxylgenation strain Aspergillus flavus AF-ANo208, a red pigment is derived, which will affect the isolation and purification of the target product. Low energy io...In the process of the fermentation of steroid C11α-hydroxylgenation strain Aspergillus flavus AF-ANo208, a red pigment is derived, which will affect the isolation and purification of the target product. Low energy ion beam implantation is a new tool for breeding excellent mutant strains. In this study, the ion beam implantation experiments were performed by infusing two different ions： argon ion （Ar^＋） and nitrogen ion （N^＋）. The results showed that the optimal ion implantation was N^＋ with an optimum dose of 2.08- 1015 ions/cm^2, with which the mutant strain AF-ANm16 that produced no red pigment was obtained. The strain had high genetic stability and kept the strong capacity of C11α-hydroxylgenation, which could be utilized in industrial fermentation. The differences between the original strain and the mutant strain at a molecular level were analyzed by randomly amplified polymorphic DNA （RAPD）. The results indicated that the frequency of variation was 7.00%, which would establish the basis of application investigation into the breeding of pigment mutant strains by low energy ion implantation.展开更多
The harmof Aspergillus flavus(A.flavus)and aflatoxin is a severe food safety problemworldwide,which causes huge economic losses every year.Therefore,it is urgent to control the growth of A.flavus and the biosynthesis ...The harmof Aspergillus flavus(A.flavus)and aflatoxin is a severe food safety problemworldwide,which causes huge economic losses every year.Therefore,it is urgent to control the growth of A.flavus and the biosynthesis of aflatoxin.Plant-derived natural compounds are superior to synthetic fungicide in inhibiting the growth of A.flavus benefiting from their high safety to the environment,humans and stock,and low cost.This study aimed to evaluate the antifungal effects and potential antifungal mechanisms of three plant-derived compounds(octanal,nonanal and decanal)against A.flavus.We determined the minimum inhibitory concentrations(MICs)and action mechanism of the three volatile aldehydes on A.flavus and also performed calcofluor white(CW)staining for visualizing the distribution of septa.Cell respiration metabolism and the pathogenicity on maize kernels were also carried out to evaluate the efficacy of the three volatile aldehydes on the growth of A.flavus.The results showed that the three volatile aldehydes could inhibit the germination of spores and mycelial growth of A.flavus,the MICs on spores and mycelia were:octanal(1.0 and 0.5μL/mL),nonanal(0.5 and 2.0μL/mL),and decanal(1 and 5μL/mL).The three volatile aldehydes could strongly damage the integrity of both the cell wall and the cell membrane of A.flavus.Meanwhile,they could decrease the content of total lipid and inhibit respiration metabolism of A.flavus cell.Results of in vitro antifungal test showed that all the three volatile aldehydes could effectively prevent the growth of A.flavus on maize kernels.The study revealed that octanal,nonanal and decanal could effectively inhibit the growth of A.flavus both in culture medium and on maize kernels to different extent.The results confirmed that the plant-derived compounds could be developed into promising antifungal agents applied in the preservation of grains.This study provides a theoretical basis for the research and application of potential antifungal agents.展开更多
There was an obvious relationship between seed testa structure, storage material and resistance to A. flavus of peanut. Results showed that seed testa of peanut germplasm with high resistance （HR） to A. flavus infec...There was an obvious relationship between seed testa structure, storage material and resistance to A. flavus of peanut. Results showed that seed testa of peanut germplasm with high resistance （HR） to A. flavus infection had thicker wax layer, integrated and tight epidermis layer, regular vascular tissue range. However, the seed testa of peanut germplasm with high sensitivity （HS） to A. flavus had the reverse results, and results of those with medium resistance （MR） to A. flavus lay in between, but changes of testa thickness were not significant among different resistance kinds. Results also showed that some seed storage materials were closely related with resistance potential to A. flavus. It seemed that varieties with higher resistance to A. flavus had higher oleic acid and protein content, lower linoleic acid and fat content. Content of palm acid, total sugar and VE did not show positive relationship with the resistance to A. flavus.展开更多
Aquatic fungi are common in various aqueous environments and play potentially crucial roles in nutrient and carbon cycling as well as interacting with other organisms. Species of Aspergillus are the most common fungi ...Aquatic fungi are common in various aqueous environments and play potentially crucial roles in nutrient and carbon cycling as well as interacting with other organisms. Species of Aspergillus are the most common fungi that occur in water. The present study was undertaken to elucidate the efficacy of two coagulants, aluminum sulfate and ferric chloride, used at different concentrations to treat drinking water, in removing Aspergillusflavus, as well as testing three different filtration media： sand, activated carbon, and ceramic granules, for their removal of fungi from water. The results revealed that both coagulants were effective in removing fungi and decreasing the turbidity of drinking water, and turbidity decreased with increasing coagulant concentration. Also, at the highest concentration of the coagulants, A. flavus was decreased by 99.6% in the treated water. Among ceramic granules, activated carbon, and sand used as media for water filtration, the sand and activated carbon filters were more effective in removing A.flavus than ceramic granules while simultaneously decreasing the turbidity levels in the test water samples. Post-treatment total organic carbon （TOC） and total nitrogen （TN） concentrations in the experimental water did not decrease; on the contrary, TN concentrations increased with the increasing dosage of coagulants. The filtration process had no effect in reducing TOC and TN in tested water.展开更多
We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ...We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.展开更多
Aflatoxin contamination in peanuts is a major threat to public health, especially in tropical and subtropical regions of the world. Recently, the use of atoxigenic Aspergillus flavus strains as biological control agen...Aflatoxin contamination in peanuts is a major threat to public health, especially in tropical and subtropical regions of the world. Recently, the use of atoxigenic Aspergillus flavus strains as biological control agents prove to be effective in reducing aflatoxin contamination in crops. A total of 208 atoxigenic A. flavus isolates, collected from peanut kernels, were grouped into 7 deletion patterns by quadruplex PCR products of nor-1, ver-1, aflR and omtA genes. 49 SNPs, found in 1254 bp fragment of omtA gene, showed genetic variation of omtA among different A. flavus isolates. These isolates were assigned to either MAT1-1 type or MAT1-2 type with primers for each MAT locus. Thus, rich genetic diversity was found in the atoxigenic A. flavus isolates of peanut in China. The results indicated that quadruplex PCR would be an effective method for rapid screening of atoxigenic isolates with gene deletion in aflatoxin biosynthetic cluster.展开更多
An Aspergillus section/Zam isolate （ NAFFHB396） was isolated from a peanut kernel. It was identified as Aspergillus flavus based on morphology and molecular characteristics. It produced yellow to green - ...An Aspergillus section/Zam isolate （ NAFFHB396） was isolated from a peanut kernel. It was identified as Aspergillus flavus based on morphology and molecular characteristics. It produced yellow to green - colored conidia on CYA medium and colonies with bright orange in color on AFPA medium. NAFFHB396 was grouped with A. flavus NRRL21882 and NRRL3357 by phylogenetic analysis of partial calmodulin sequence data. It was found that 12 genes were absent in aflatoxin gene cluster in NAFF- HB396. HPLC result further showed that it was an atoxigenic isolate. Co - inoculation of NAFFHB396 with a high aflatoxin producer AF2202 at the ratio of 1：1 both on CYA medium and peanut kernel resul-ted in reduction of aflatoxin production by 88.7% and 99. 8% respectively. These results suggested that the atoxigenic NAFFHB396 obtained in this study had a great potential to be a biocontrol agent to reduce aflatoxin contamination of peanut in China.展开更多
基金supported by the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202416)the Foundation of Hubei Hongshan Laboratory(2021hszd015)+1 种基金the Science and Technology Major Projects of Hubei Province(2023BBA002)the Knowledge Innovation Program of Wuhan-Basi Research(2023020201010126)。
文摘Peanuts are important oilseed legume crops that are susceptible to contamination by Aspergillus flavus in soil,leading to serious economic losses.Previously,our research team developed the Aspergillus-Rihizobia coupling(ARC)microbial inoculants and found it can reduce A.flavus abundance in the soil and promote efficient nodulation in peanuts.However,the impact of ARC microbial inoculants on different resistant varieties of A.flavus remains unclear.In this study,we screened peanut varieties that were resistant and susceptible to A.flavus and evaluated their nodulation ability and growth performance after ARC microbial inoculants treatment in the field.The results demonstrated that the nodule number and nitrogenase activity of both varieties significantly increased after ARC microbial inoculants treatment,with the highly susceptible variety AH24 showing a greater increase.For photosynthetic parameters,both varieties also increased after ARC microbial inoculants treatment,but the increase was greater in the moderately resistant variety AH1 than in the highly susceptible variety AH24.Finally,we found that the yield and yield-related traits of the moderately resistant variety AH1 were better than those of the highly susceptible variety AH24.After ARC microbial inoculants treatment,the yield traits of both peanut varieties still increased significantly,but the degree of increase of the moderately resistant variety AH1 was smaller than that of the highly susceptible variety AH24.In addition,the abundance of A.flavus in the rhizosphere soil of the two varieties significantly decreased after ARC microbial inoculants treatment,with no significant difference between the varieties.These results indicated that ARC microbial inoculants exert differential effects on the nodulation and growth of different resistant peanut varieties and have a better effect on highly susceptible varieties.These results provide a solid theoretical basis for the efficient use of ARC microbial inoculants in the field of peanuts in the future.
文摘In nature, plant extracts play a crucial role in defending plants against biotic and abiotic stressors. Moreover, the use of plant-based products, such as plant extracts, represents a promising alternative to synthetic fungicides, which pose potential health risks to consumers. In this study, the antifungal activity of the essential oils (EOs) of Lippia multiflora, Eucalyptus camaldulensis and Ocimum americanum was evaluated against two strains of Aspergillus flavus via the agar dilution method. These two Aspergillus flavus fungi was isolated from Bamabra groundnut seeds. Lippia multiflora essential oil (EO) showed the best results compared with the other oils, with a minimum inhibitory concentration (MIC) of 9000 μg∙mL−1. The MIC for Eucalyptus camaldulensis and Ocimum americanum EOs was 10,800 μg∙mL−1. In view of their antifungal properties, these EOs could be used to develop a new, safe antifungal agent for food preservation.
基金Supported by Natural Science Foundation of Hainan Province(809034)National Nonprofit Institute Research Grant of CATAS-TCGRI(1630032012025)~~
文摘In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different peanut varieties to the inoculation with A. flavus has not been investigated and might be useful for breed- ing resistant peanut cultivars. In this study, peanut varieties resistant or susceptible to aflatoxin accumulation caused by A. flavus were selected to compare the synthe- sis differences of the four main stilbenes （resveratrol, ε-viniferin, 6-viniferin and pterostilbene） and the activities of their resistant enzymes （PAL, POD, PPO）, and explore the relationship between stilbene synthesis and resistance to aflatoxin accu- mulation. The results indicated that the synthesis speed of stilbenes was related to the resistance to aflatoxin accumulation in peanuts seeds. The total content of the four stilbenes reached the highest value of 47.37 μg/g in the resistant cultivars （Qian huasheng 3） after inoculation by A. flavus （54 times of the control） on the 3nd day, while the total content of stilbenes in susceptible cultivars （Huayu 22） was 5.5 μg/g. The content of stilbenes and the activities of their resistant enzymes from the resistant cultivars were both higher than from the susceptible one. The four peanut varieties with relative higher stilbene contents and lower disease index and aflatoxin content were selected by using the stilbene content. Very significant negative corre- lation, with correlation coefficients （r） of -0.789, -0.851 and -0.850, was observed between the stilbene content with disease index, the content of aflatoxin B1 and the total content of aflatoxins, respectively. Therefore, the study suggested that the total content of stilbene compounds might serve as an important chemical index in peanut seeds after inoculation with A. flavus on the 3nd day, during screening and breeding of peanut varieties resistant to aflatoxin accumulation.
基金supported by the Natural Science Foundation of Guangxi(No.2020GXNSFGA297002)the Specific Research Project of Guangxi for Research Bases and Talents(No.AD20297003)+3 种基金the Special Fund for Bagui Scholars of Guangxi(Y.Liu)the National Natural Science Foundation of China(Nos.U20A20101,22007019)the Key State Laboratory Talent Project of Guangxi Normal University(No.CMEMR 2019-A05)the Open Project of CAS Key Laboratory of Tropical Marine Bioresources and Ecology(No.LMB20211005).
文摘A new oxygenated tricyclic cyclopiazonic acid(CPA)alkaloid,asperorydine Q(1),along with seven known compounds,namely,asperorydines O(2)and J(3),speradine H(4),cyclopiamides A(5)and H(6),saadamysin(7),and pyrazinemethanol(8),were isolated from the coral-associated Aspergillus flavus GXIMD 02503.The structures were elucidated by physicochemical properties and comprehensive spectroscopic data analysis.Compounds 1−5 and 7−8 exhibited potent inhibition of lipopolysaccharide(LPS)-induced nuclear factor-κB(NF-κB)with the IC50 values ranging from 6.5 to 21.8μmol L^(−1).In addition,the most potent one,pyrazinemethanol(8),dose-dependently suppressed receptor activator of NF-κB ligand(RANKL)-induced osteoclast differentiation without obvious cytotoxicity in bone marrow macrophages cells(BMMCs),suggesting it is a promising lead compound for the treatment of osteolytic diseases.
文摘Fungi produce a variety of microbial volatile organic compounds (MVOCs) during primary and secondary metabolism. The fungus, Aspergillus flavus, is a human, animal and plant pathogen which produces aflatoxin, one of the most carcinogenic substances known. In this study, MVOCs were analyzed using solid phase microextraction (SPME) combined with GCMS from two genetically different A. flavus strains, an aflatoxigenic strain, NRRL 3357, and a non-aflatoxigenic strain, NRRL 21882. A PDMS/CAR SPME fiber was used over 30 days to observe variations in MVOCs over time. The relative percentage of individual chemicals in several chemical classes (alcohols, aldehydes, esters, furans, hydrocarbons, ketones, and organic acids) was shown to change considerably during the varied fungal growth stages. This changing chemical profile reduces the likelihood of finding a single chemical that can be used consistently as a biomarker for fungal strain identification. In our study, discriminant analysis techniques were successfully conducted using all identified and quantified MVOCs enabling discrimination of the two A. flavus strains over the entire 30-day period. This study underscores the potential of using SPME GCMS coupled with multivariate analysis for fungi strain identification.
基金supported by the National Natural Science Foundation of China (30771353)the Natural Science Foundation of Jiangsu Province, China(BK2007078)the Open Subject of Key Laboratory of Plant Functional Genomics,Ministry of Education of China (K06003)
文摘Maize （Zea mays L.）, one of main crops in the world, is easily susceptible to Aspergillusflavus （Link： fr） infection, resulting huge loses worldwide. Breeding for A. flavus resistance has been proved an efficient way to solve the problem of aflatoxin contamination. Genetic analysis of the sources of resistance to A.flavus in maize is necessary for this purpose. The complete diallel crosses of 6 inbred lines with different resistance to A.flavus infection were implemented. Inoculation categorical data of each cross were analyzed with the additive-dominant and additive-dominant-epitasis genetic models. Results indicated some crosses fitted the 2 major genes with additive-dominant-epitasis genetic model. Others fitted the major gene and polygene mixed model. Moreover, the additive, dominant, and epitasis effects varied in crosses. The A.flavus resistance was controlled by both major gene and polygene.
基金the financial support of the Doctor Research Fund of Henan University of Technology(2019BS019)the Natural Science Research Projects of Education Department of Henan Province(21A550005)the Innovative Funds plan of Henan University of Technology(2020ZKCJ17)。
文摘To study the structure-antifungal activity of vanillin against Aspergillus flavus(A.flavus),the susceptibilities of A.flavus to vanillin and its isomers(o-vanillin,2-hydroxy-4-methoxybenzaldehyde(HMB),2-hydroxy-5-methoxybenzaldehyde)and the possible antifungal mechanisms have been investigated.All the four volatile aldehydes could inhibit the germination of spores,and the minimum inhibitory concentrations(MICs)of them were in this order:vanillin(200μg/mL),o-vanillin(100μg/mL),2-hydroxy-5-methoxybenzaldehyde(100μg/mL),HMB(70μg/mL).The minimum fungicidal concentrations(MFCs)of them were in this order:vanillin(240μg/mL),o-vanillin(160μg/mL),HMB(140μg/mL),2-hydroxy-5-methoxybenzaldehyde(140μg/mL).Spore size was arrested at 0 h with the treatment of the four volatile aldehydes.Effects of the four volatile aldehydes on the cell wall and cell membrane integrity of A flavus were observed by calcofluor white(CW)staining and propidium iodide(PI)staining.The results showed that HMB exerted the strongest antifungal and fungicidal effects on the growth of A.flavus.The four volatile aldehydes had little influence on cell wall integrity after 3-hour treatment,however,they could strongly damage the cell membrane integrity.All the four volatile aldehydes could effectively prevent the growth of A.flavus on peanut seeds.The antifungal mechanisms of the four volatile aldehydes provide theoretical foundations for their development of new antifungal agents.
基金supported by the Key Lab of Biomass and Energy of Anhui Educational Department of China
文摘In the process of the fermentation of steroid C11α-hydroxylgenation strain Aspergillus flavus AF-ANo208, a red pigment is derived, which will affect the isolation and purification of the target product. Low energy ion beam implantation is a new tool for breeding excellent mutant strains. In this study, the ion beam implantation experiments were performed by infusing two different ions： argon ion （Ar^＋） and nitrogen ion （N^＋）. The results showed that the optimal ion implantation was N^＋ with an optimum dose of 2.08- 1015 ions/cm^2, with which the mutant strain AF-ANm16 that produced no red pigment was obtained. The strain had high genetic stability and kept the strong capacity of C11α-hydroxylgenation, which could be utilized in industrial fermentation. The differences between the original strain and the mutant strain at a molecular level were analyzed by randomly amplified polymorphic DNA （RAPD）. The results indicated that the frequency of variation was 7.00%, which would establish the basis of application investigation into the breeding of pigment mutant strains by low energy ion implantation.
基金This study was funded by the Doctor Research Fund of Henan University of Technology(grant number 2019BS019)the Natural Science Research Projects of Education Department of Henan Province(21A550005).
文摘The harmof Aspergillus flavus(A.flavus)and aflatoxin is a severe food safety problemworldwide,which causes huge economic losses every year.Therefore,it is urgent to control the growth of A.flavus and the biosynthesis of aflatoxin.Plant-derived natural compounds are superior to synthetic fungicide in inhibiting the growth of A.flavus benefiting from their high safety to the environment,humans and stock,and low cost.This study aimed to evaluate the antifungal effects and potential antifungal mechanisms of three plant-derived compounds(octanal,nonanal and decanal)against A.flavus.We determined the minimum inhibitory concentrations(MICs)and action mechanism of the three volatile aldehydes on A.flavus and also performed calcofluor white(CW)staining for visualizing the distribution of septa.Cell respiration metabolism and the pathogenicity on maize kernels were also carried out to evaluate the efficacy of the three volatile aldehydes on the growth of A.flavus.The results showed that the three volatile aldehydes could inhibit the germination of spores and mycelial growth of A.flavus,the MICs on spores and mycelia were:octanal(1.0 and 0.5μL/mL),nonanal(0.5 and 2.0μL/mL),and decanal(1 and 5μL/mL).The three volatile aldehydes could strongly damage the integrity of both the cell wall and the cell membrane of A.flavus.Meanwhile,they could decrease the content of total lipid and inhibit respiration metabolism of A.flavus cell.Results of in vitro antifungal test showed that all the three volatile aldehydes could effectively prevent the growth of A.flavus on maize kernels.The study revealed that octanal,nonanal and decanal could effectively inhibit the growth of A.flavus both in culture medium and on maize kernels to different extent.The results confirmed that the plant-derived compounds could be developed into promising antifungal agents applied in the preservation of grains.This study provides a theoretical basis for the research and application of potential antifungal agents.
文摘There was an obvious relationship between seed testa structure, storage material and resistance to A. flavus of peanut. Results showed that seed testa of peanut germplasm with high resistance （HR） to A. flavus infection had thicker wax layer, integrated and tight epidermis layer, regular vascular tissue range. However, the seed testa of peanut germplasm with high sensitivity （HS） to A. flavus had the reverse results, and results of those with medium resistance （MR） to A. flavus lay in between, but changes of testa thickness were not significant among different resistance kinds. Results also showed that some seed storage materials were closely related with resistance potential to A. flavus. It seemed that varieties with higher resistance to A. flavus had higher oleic acid and protein content, lower linoleic acid and fat content. Content of palm acid, total sugar and VE did not show positive relationship with the resistance to A. flavus.
基金supported by the National High-Tech Research and Development Program (863) of China (No. 2012AA062607)the National Natural Scientific Foundation of China (No. 51278482, 51108440)the 100 Talents Program of Chinese Academy of Sciences
文摘Aquatic fungi are common in various aqueous environments and play potentially crucial roles in nutrient and carbon cycling as well as interacting with other organisms. Species of Aspergillus are the most common fungi that occur in water. The present study was undertaken to elucidate the efficacy of two coagulants, aluminum sulfate and ferric chloride, used at different concentrations to treat drinking water, in removing Aspergillusflavus, as well as testing three different filtration media： sand, activated carbon, and ceramic granules, for their removal of fungi from water. The results revealed that both coagulants were effective in removing fungi and decreasing the turbidity of drinking water, and turbidity decreased with increasing coagulant concentration. Also, at the highest concentration of the coagulants, A. flavus was decreased by 99.6% in the treated water. Among ceramic granules, activated carbon, and sand used as media for water filtration, the sand and activated carbon filters were more effective in removing A.flavus than ceramic granules while simultaneously decreasing the turbidity levels in the test water samples. Post-treatment total organic carbon （TOC） and total nitrogen （TN） concentrations in the experimental water did not decrease; on the contrary, TN concentrations increased with the increasing dosage of coagulants. The filtration process had no effect in reducing TOC and TN in tested water.
文摘We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast Extract Sucrose Agar medium and aflatoxins quantified using LCMSMS. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.
基金supported by the Special Program for Basic Research of the Ministry of Science and Technology (2013FY113400)Chinese Agriculture Research System under Grant No. CARS-14the National Natural Science Foundation of China under Grant No. 31371662 and 31464443022
文摘Aflatoxin contamination in peanuts is a major threat to public health, especially in tropical and subtropical regions of the world. Recently, the use of atoxigenic Aspergillus flavus strains as biological control agents prove to be effective in reducing aflatoxin contamination in crops. A total of 208 atoxigenic A. flavus isolates, collected from peanut kernels, were grouped into 7 deletion patterns by quadruplex PCR products of nor-1, ver-1, aflR and omtA genes. 49 SNPs, found in 1254 bp fragment of omtA gene, showed genetic variation of omtA among different A. flavus isolates. These isolates were assigned to either MAT1-1 type or MAT1-2 type with primers for each MAT locus. Thus, rich genetic diversity was found in the atoxigenic A. flavus isolates of peanut in China. The results indicated that quadruplex PCR would be an effective method for rapid screening of atoxigenic isolates with gene deletion in aflatoxin biosynthetic cluster.
文摘An Aspergillus section/Zam isolate （ NAFFHB396） was isolated from a peanut kernel. It was identified as Aspergillus flavus based on morphology and molecular characteristics. It produced yellow to green - colored conidia on CYA medium and colonies with bright orange in color on AFPA medium. NAFFHB396 was grouped with A. flavus NRRL21882 and NRRL3357 by phylogenetic analysis of partial calmodulin sequence data. It was found that 12 genes were absent in aflatoxin gene cluster in NAFF- HB396. HPLC result further showed that it was an atoxigenic isolate. Co - inoculation of NAFFHB396 with a high aflatoxin producer AF2202 at the ratio of 1：1 both on CYA medium and peanut kernel resul-ted in reduction of aflatoxin production by 88.7% and 99. 8% respectively. These results suggested that the atoxigenic NAFFHB396 obtained in this study had a great potential to be a biocontrol agent to reduce aflatoxin contamination of peanut in China.
