Gene Mapping And Preliminary Functional Analysis Of Maize Vivipary Mutants

Vivipary(穗发芽)is one of the main disaster for crops,is often directly related to the plant endogenous hormone abscisic acid(ABA).Molybdenum cofactors(Mo Co)which directly affect ABA synthesis,but its role in vivipary of maize is unclear so far.Therefore,the researchs about Mo Co-related maize vivipary mutants could not only provide information for in-depth understanding of regulation mechanism of vivipary,but also offer materials for maize stress resistance breeding.In this study,preliminary analysis were carried out on two maize vivipary mutants caused by two molybdenum cofactor mutations.For the mutant vp-like5,the candidate gene,which encodes GRMZM2G165966,was fined mapped and cloned.Moreover,the subcellular localization of the candidate gene was carried out.In addition,for another mutant vp-like4,RNA-Seq were conducted using an F2 population to obtain the differentially expressed genes(DEGs).The Gene ontology(GO)analysis were performed to analyze the possible regulatory pathway.The main results are listed as follows:1.The fine mapping of vp-like5.An F2 population were constructed by crossing vp-like5 mutant and Mo17.The seeds with vivipary phenotype were selected for genotyping detection by the polymophic makers.Finally,the candidate interval was narrowed to a 258 kb region on chromosome 4,which contained 17 genes.2.Cloning of the vp-like5.The expression level of the genes in candidate interval were analyzed by RT-PCR and RNA-seq data.The results showed GRMZM2G165966,which was related to the biosynthesis of Molybdenum Cofactor(Mo Co),did not expressed in mutant and was considered as the candidate gene of vp-like5.3.The subcellular localization of vp-like5.The candidate gene GRMZM2G165966 was introduced into the p Earley Gate104 vector,transiently expressed in maize protoplasts and tobacco mesophyll cells.The results indicated that GRMZM2G165966 was mainly expressed in cell membranes,nuclei and organelles.4.RNA-seq Analysis of vp-like4 mutant.A total of 3376 DEGs(2252 up-regulated,1124 down-regulated)were identified between WT and vp-like5,including the candidate gene GRMZM2G121468(down-regulated).The GO functional enrichment analysis showed that DEGs were enriched in 716 GO items.In summary,364 items were enriched in biological process,72 items related to cellular component and 280 items related to molecular function.Among them,the significantly influenced items in biological functions were enriched in plant stress responses,carbohydrate metabolism and photosynthesis,which were all associated with seed dormancy.The results of KEGG analysisshowed that the DEGs were especially enriched in signal transduced pathway including plant hormone signal transduction,carotenoid biosynthesis,photosynthesis and starch and sucrose metabolism.Therefore,the DEGs involved in different metabolic pathways provide deeper understanding for regulatory network of vivipary mutant.