Differential Expression And Its Effect Analysis Of GA-related Genes In TaGW2-6A Allelic Variationduring Wheat Seed Development

Gibberellins are involved in seed development,which is reflected by the contributions of GA perception and signal transduction.E3 ubiquitin-ligases in particular actively participate in GA perception and signal transduction.TaGW2-6A encodes RING E3 ubiquitin-ligase which could negatively regulate grain size.Here,we investigated the transcriptional coordination of GA-related genes and analyzed the difference transcription expression in TaGW2-6A during grain filling.The main results are concluded as follows:1.Grain filling and dry matter accumulation rate of wheat were closely related to grain weight.The fresh and dry weight ofNIL31 were higher than that of CS.At the same time,we found that dry matter accumulation rate in NIL31 was significantly higher than of CSat 9-20 days.The results showed that TaGW2-6A allele variation could control the grain size by affecting grain filling and accumulation rate of dry matter.2.Real-time quantitative PCR results showed that GA synthesis(GA 3-oxidase)and GA response gene(GASA4)had higher expression level in NIL31 than that in CS.Otherwise,GA had higher level in NIL31.This result indicating that the high level of GA through GA 3-oxidasewhichinfluenced the expression of GASA4 to promote endosperm cell division and development in NIL31,thus affecting the size of the seed.In addition,the expression pattern of GA related genes and TaGW2-6A showed that there were negatively correlated relationships between them.3.When cultivated with GA,the endosperm number increased and became larger in CS.In addition,the expression levels of GA 3-oxidase and GASA4 increased andGA had higher level in CS.These results showed that GA promoted the expression of GA 3-ox and GASA4 genes in CS,which in turn led to the development of endosperm cells.However,NIL31 medium endosperm cells become smaller,the number decreased,the grain smaller.In addition,GA had lower level in NIL31,GASA4 expression levels decreased,GA 3-oxidase levels were significantly increased.GA can positively regulate GA3-oxidase to regulate the GA balance in plants.This result showed that TaGW2-6A allele variation has high levels of GA,resulting in negative feedback regulation of GA 3-oxidase.4.NIL31 had a higher germination rate rate than that of CS,and the stems growth rate was significantly higher than that of in CS.In addition,GA had higher level in NIL31 than CS,showed that the high level of GA through GA relatead genes,which promote the seed germinationand the whole plant growth processin NIL31.After GA treatment,the germination experiments showed that CS and NIL31 had the opposite germination effect.At the same time,after the seeds were treated with GA during seed development,they had the same potential for germination as the seeds without GA treatment.It can be seen that the higher level of GA in the plant,which negatively feedback regulation and the expression of GASA4 to affects the seed development.We hypothesized that TaGW2-6A acted synergistically with GA to regulate wheat grain development.