A Broad Spectrum Identification Approach for Two Generations of epsps GM Soybeans

In order to accurately identify the first and second generations of epsps genetically modified(GM) soybeans and related products,a broad spectrum identification approach was established using the real time Polymerase Chain Reaction(PCR) principle according to the homology of epsps genes of the first and second generations of GM soybeans.A pair of primer and probe was designed to simultaneously identify exogenous gene epsps of two generations of GM soybeans.Besides,evaluation was carried out on this approach from the accuracy,specificity,sensitivity and reproducibility.The experimental results indicated that(ⅰ) although there is certain difference in epsps gene sequence between the first and second generations of epsps genetically modified(GM) soybeans,the established approach can simultaneously detect the epsps genes of the bean curd using two generations of soybean as raw materials;(ⅱ) in the accuracy and specificity experiment,only cp4-epsps genes of two generations of GM soybeans were detected,so this approach has high specificity and accuracy;(ⅲ) in the experiment of 5 copies of epsps genes of 40 repeated identification reaction systems,5 copies of epsps genes can be detected each time,therefore at 100% confidence level,this approach can identify 5 copies of epsps genes,showing that this approach has high sensitivity and reproducibility.

Target Resistance of Eleusine indica to Glyphosate

[Objectives]This study was conducted to detect the evolution of resistance to glyphosate in Eleusine indica.[Methods]In the previous study,glyphosate-resistant population T2-4 was screened out from E.indica populations in sugarcane fields in Guangxi.In this study,we determined the resistance index of T2-4 by whole plant bioactivity assay and further explored the molecular biological mechanism of resistance.[Results]The resistance index of T2-4 was 112,and it is thus a highly resistant population.Amino acid mutations were found at positions 102,106 and 381 in the EPSPS sequence of T2-4,containing at least a triple mutation allele in Thr-102-Ile,Pro-106-Ser and Pro-381-Leu and a double mutation allele in Pro-106-Ser and Pro-381-Leu.qPCR was used to determine the EPSPS gene copy number and expression in resistant plants of T2-4.EPSPS gene copy number and expression both increased,with 8.3-fold higher copy number and 2.7-fold higher expression than the sensitive population.Therefore,the resistance of T2-4 to glyphosate was mainly caused by multiple target mechanisms including mutation of EPSPS gene,copy number increase and expression increase,and the resistance of E.indica to glyphosate needs our high attention.[Conclusions]At present,the level of resistance to glyphosate is very high in the sugarcane fields of Guangxi,and it is necessary to take a variety of weed control measures to solve the problem of glyphosate resistance.