Improvement Of Maize Overexpression Mutant Generation System And Identification Of Mutants

Maize(Zea mays L.)is a widely used crop,and plays a very important role in the people’s livelihood and economic development.The function analysis of maize genes by mutants is of great significance for maize variety improvement.In our laboratory,we preliminatively built a maize overexpression mutant generation system by combining maize Ac/Ds transposons and overexpression tag generation line technology.In this study,the overexpression mutant generation system was supplemented and mutant screening and identification were carried out.The main research results are as follows:1.Three maize overexpression mutant lines DATTL-68,DATTL-69 and DATTL-70 were created.The transposition frequencies of artificial transposons were 42.50%,33.10% and 37.10%,respectively.2.Two transposon lines were constructed: Zm Ds-697-Transposon line and Zm DsRsc-Bar-Transposon line.TAIL-PCR and resequencing techniques were used to identify TDNA insertion sites of transposon lines and isolate flank sequences,and T-DNA insertion sites of 18 transposon lines were obtained.The number of the 54 lines established in the laboratory was increased to 72,and the transposon lines on the short arm of chromosome 8were added,and the core population of maize overexpression mutant generation system was initially established3.During the four sowing seasons from 2021 to 2022,the overexpressed mutant lines of maize were screened under conventional agronomic conditions,and hundreds of mutant plants with phenotypic variation were obtained,covering plant shape,leaf color,leaf morphology,growth potential and the developmental morphology of male and female ears of maize.Among them,7 mutant characters could be inherited stably.4.The mutant with stable character inheritance was identified and the candidate gene was determined.Resequencing technology was used to isolate and locate the LW(Leaf Width)artificial transposon tag insertion site located on chromosome 7 of maize genome:At 128326215 bp,insert the 5’end of the CDS sequence of GRMZM2G095254 gene at 59 bp.Four candidate genes were predicted: GRMZM2G095254,GRMZM2G308503,GRMZM2G396350,GRMZM2G161619.In this study,the generation system of maize overexpression mutants was supplemented and improved,and the overexpression mutants were screened.The mutants with stable inheritance were selected for study,candidate genes were predicted,and a standardized process was explored for the application of the generation system of maize overexpression mutants,which promoted the construction process of large maize overexpression mutants library.