Yuqu River Basin in Tibet is not involved area during previous vegetation investigations.Buxus rugulosa community was first discovered in Yuqu River Basin in Tibet,which would increase a new vegetation type.The discov...Yuqu River Basin in Tibet is not involved area during previous vegetation investigations.Buxus rugulosa community was first discovered in Yuqu River Basin in Tibet,which would increase a new vegetation type.The discovery will provide extremely important material on study of occurrence,origin,community structure and function of the vegetation type.展开更多
In order to establish a fast and effective high-throughput method for identifying maize resistance to Aspergillus flavus infection in the field,5 conidial concentrations and 3 inoculation methods were compared and opt...In order to establish a fast and effective high-throughput method for identifying maize resistance to Aspergillus flavus infection in the field,5 conidial concentrations and 3 inoculation methods were compared and optimized. A correlation model between disease levels and aflatoxin B1 accumulation was established. The results showed that inoculating maize inbred lines with the optimal conidial concentration of 1.0×10^6 c/mL could accurately show the different resistance levels of maize to A.flavus infection,and the spiral quantitative inoculation technique could effectively avoid the defect of calculation error caused by commonly used methods. The positive correlation model of resistance level and aflatoxin B1 accumulation could effectively predict the capability of maize being resistant to A.flavus. 8 resistant and 9 medium resistant maize inbred lines of the RIL population were identified.The spiral quantitative identification method realized the high-throughput identification of maize inbred lines resistant to A.flavus infection in the field,and the results have shown high accuracy,stability and repeatability.展开更多
Aspergillus flavus maize colonization leads to crop contamination by toxic secondary metabolites and carcinogens called aflatoxins （AF）; it has negative effects in public health and has caused economic losses in agr...Aspergillus flavus maize colonization leads to crop contamination by toxic secondary metabolites and carcinogens called aflatoxins （AF）; it has negative effects in public health and has caused economic losses in agricultural activities. Eleven genotypes of immature maize grain frequently used in Mexico were inoculated in vitro with two indigenous toxigenic strains ofA. flavus. The size of inoculum, temperature, humidity and presence of other phytopathogens were assessed. Genotypes Popcorn, C-526, Garst 8366, As910 and 30G40 showed resistance to rating of fungal colonization （FC） and AF accumulation, while 3002W, 30R39, Creole, C-922, HV313 and P3028W genotypes were less resistant. AFB~ had the highest concentrations （26.1 mg/kg ± 14.7 mg/kg）, while AFB2, AFG1 and AFG2 showed only residual concentrations 1.6, 2.0 and 4.0 ~tg/kg, respectively. Concerning FC and AF, there were significant differences （P 〈 0.01） between strains and genotype. Both strains showed significant association （P 〈 0.01） between FC and the concentrations of AFB1 and AFB2 （R2： 99.5% and 93.2%; 87.2% and 73.2%, respectively）. Results suggest that the level of resistance to fungus infection and AF accumulation is related to maize genotype. It emphasizes the relevance of developing A. flavus resistant maize genotypes as an alternative to control contamination in foodstuff intended for human and animal consumption.展开更多
The maximal deoxynivalenol （DON） and fumonisins 131 ＋ B2 （FUM） contents in cereals are dictated by the European regulation 1126/2007. The direct measurement of these mycotoxins is a tedious and expensive process....The maximal deoxynivalenol （DON） and fumonisins 131 ＋ B2 （FUM） contents in cereals are dictated by the European regulation 1126/2007. The direct measurement of these mycotoxins is a tedious and expensive process. Our study is based on an alternative tool： near infrared spectroscopy. Different models were developed on 374 maize samples to predict their DON and FUM contents. Several parameters have been determined and used in a multivariate data analysis. Three models were developed： （1） a classification model based on Discriminant Factor Analysis （DFA）, （2） a linear model based on ANalysis of COVAriance （ANCOVA） and （3） a Partial Least Squares Discriminant Analysis model （PLS-DA）. Firstly, the performances of the DFA model for assessing DON and FUM risk were similar： 69 and 72% of the validation samples were respectively well classified. In the second part, the performances of the ANCOVA model for DON were higher than for FUM. The r2 was worth respectively 0.85 and 0.69. In the last part, the performances of the PLS-DA models were better for FUM than for DON. These results show that an evaluation of the mycotoxin risk is possible by analyzing selected kernel parameters measurable by secondary analytical such as near-infrared spectroscopy. Further work is needed to improve the models, adding more samples and using non linear approaches.展开更多
文摘Yuqu River Basin in Tibet is not involved area during previous vegetation investigations.Buxus rugulosa community was first discovered in Yuqu River Basin in Tibet,which would increase a new vegetation type.The discovery will provide extremely important material on study of occurrence,origin,community structure and function of the vegetation type.
文摘In order to establish a fast and effective high-throughput method for identifying maize resistance to Aspergillus flavus infection in the field,5 conidial concentrations and 3 inoculation methods were compared and optimized. A correlation model between disease levels and aflatoxin B1 accumulation was established. The results showed that inoculating maize inbred lines with the optimal conidial concentration of 1.0×10^6 c/mL could accurately show the different resistance levels of maize to A.flavus infection,and the spiral quantitative inoculation technique could effectively avoid the defect of calculation error caused by commonly used methods. The positive correlation model of resistance level and aflatoxin B1 accumulation could effectively predict the capability of maize being resistant to A.flavus. 8 resistant and 9 medium resistant maize inbred lines of the RIL population were identified.The spiral quantitative identification method realized the high-throughput identification of maize inbred lines resistant to A.flavus infection in the field,and the results have shown high accuracy,stability and repeatability.
文摘Aspergillus flavus maize colonization leads to crop contamination by toxic secondary metabolites and carcinogens called aflatoxins （AF）; it has negative effects in public health and has caused economic losses in agricultural activities. Eleven genotypes of immature maize grain frequently used in Mexico were inoculated in vitro with two indigenous toxigenic strains ofA. flavus. The size of inoculum, temperature, humidity and presence of other phytopathogens were assessed. Genotypes Popcorn, C-526, Garst 8366, As910 and 30G40 showed resistance to rating of fungal colonization （FC） and AF accumulation, while 3002W, 30R39, Creole, C-922, HV313 and P3028W genotypes were less resistant. AFB~ had the highest concentrations （26.1 mg/kg ± 14.7 mg/kg）, while AFB2, AFG1 and AFG2 showed only residual concentrations 1.6, 2.0 and 4.0 ~tg/kg, respectively. Concerning FC and AF, there were significant differences （P 〈 0.01） between strains and genotype. Both strains showed significant association （P 〈 0.01） between FC and the concentrations of AFB1 and AFB2 （R2： 99.5% and 93.2%; 87.2% and 73.2%, respectively）. Results suggest that the level of resistance to fungus infection and AF accumulation is related to maize genotype. It emphasizes the relevance of developing A. flavus resistant maize genotypes as an alternative to control contamination in foodstuff intended for human and animal consumption.
文摘The maximal deoxynivalenol （DON） and fumonisins 131 ＋ B2 （FUM） contents in cereals are dictated by the European regulation 1126/2007. The direct measurement of these mycotoxins is a tedious and expensive process. Our study is based on an alternative tool： near infrared spectroscopy. Different models were developed on 374 maize samples to predict their DON and FUM contents. Several parameters have been determined and used in a multivariate data analysis. Three models were developed： （1） a classification model based on Discriminant Factor Analysis （DFA）, （2） a linear model based on ANalysis of COVAriance （ANCOVA） and （3） a Partial Least Squares Discriminant Analysis model （PLS-DA）. Firstly, the performances of the DFA model for assessing DON and FUM risk were similar： 69 and 72% of the validation samples were respectively well classified. In the second part, the performances of the ANCOVA model for DON were higher than for FUM. The r2 was worth respectively 0.85 and 0.69. In the last part, the performances of the PLS-DA models were better for FUM than for DON. These results show that an evaluation of the mycotoxin risk is possible by analyzing selected kernel parameters measurable by secondary analytical such as near-infrared spectroscopy. Further work is needed to improve the models, adding more samples and using non linear approaches.
