Study On Glyphosate-resistant And High Yield Transgenic Maize Expressing G10evo And Enhanced ZmTE1

Maize(Zea mays L.)yield is an extremely complex trait affected not only by the genetic factors,but also by the environmental factors.The genetic components of maize yield include the weight per ear,ear length,100-kernel weight,kernel length,and kernel width.The ZmTE1 gene belongs to the mei2-like family,whose function is illustrated initially as a regulator of the leaf development in the early stages.The mutant maize of loss of ZmTE1 function exhibit shorter internodes and decreased plant statures,as well as aberrant leaves.We previously overexpressed the rice homologous gene OsTEL in transgenic rice,and found that the yield traits,such as 1000-grain weight,grain length and grain width of transgenic rice were significantly improved.Therefore,we speculated that ZmTE1 might have the potential to increase yield as well in maize.In this study,we constructed a T-DNA vector comprising expression cassettes,one of which is a potential yield enhancing gene,ZmTE1,and the other of which is a glyphosate tolerant EPSPS gene G10evo,which serves as a selection marker for transformation as well as a useful agronomic trait for weed control.Transgenic maize events were obtained by Agrobacterium-mediated transformation.We selected AM16,which had good growth and visible differences in yield traits.PCR analysis confirmed that AM16 contained target genes of G10evo and ZmTE1.Southern blot analysis using probe for G10evo showed that insert T-DNA integrated in a single site in the naize genome.Western blot analysis showed that G10evo protein was expressed in AM 16 with a size of 48kDa,which was consistent with the size of the positive protein.Quantitative PCR analysis showed the transcription level of ZmTE1 gene was significantly higher than that of isogenic non-transgenic line in root,stem and leaves.The transcription level of ZmTE1 in stem was the highest among the different tissues,and was about 300 times higher than that of isogenic non-transgenic line.Glyphosate spray assay in the greenhouse showed that the AM 16 is tolerant to glyphosate at concentrations up to 4 times of recommended field application level.In terms of agronomic traits,the plant height and the internode distance of transgenic maize AM 16 were significantly higher compared to isogenic non-transgenic line,but the number of leaves and the number of internodes did not differ significantly from those of isogenic non-transgenic line.Ear weight,ear length,100-kernel weight,kernel length,and kernel width of the transgenic maize AM 16 increased significantly when compared with isogenic non-transgenic line,Field statistics showed that the 100-kernel weight of transgenic maize increased by 55.77%,kernel length increased by 25.55%,the weight of per ear increased by 80.79%,the differences were extremely significant.In summary,the transgenic maize AM 16 has the potential to increase maize yield in the field.