Functional Analysis Of Wheat MADS-box Gene TaAGL32

Wheat(Triticum aestivum L.)is an important food crop in China and even in the world,accounting for 40% of the world's staple food.Heading time is critical to the formation of wheat yield.It will be important for wheat genetic improvement to understand the molecular mechanism of wheat heading time.In this study,a MADS-box gene Ta AGL32 was cloned and analyzed.The main results are as follows.1)There were three copies of TaAGL32 in common hexaploid wheat,which were assigned to chromosome 7A,7B,and 7D,respectively.The near full length of three genomic DNA were 1908bp(TaAGL32-7A),1912bp(TaAGL32-7B)and 1790bp(TaAGL32-7D).They contain seven exons and six introns,and the CDS length of three genes are same 693 bp that encodes 230 amino acids.2)All TaAGL32 protein contains two conserved domains,the MEF2-like domain and the K-Box domain,belong to a kind of classic MIKC-type protein.Phylogenetic tree analysis showed that TaAGL32 had evolutionary conservatism compared with its ancestral species.The subcellular localization analysis of TaAGL32 protein showed that it was located in nucleus.3)The results of qRT-PCR showed that the expression of TaAGL32 gene was expressed highly in roots and stems,followed by in spikelets and florets.Further analysis showed that TaAGL32 genes were circadian rhythmically expressed under both long-day(LD)and short-day(SD)conditions.The expression level of TaAGL32 genes increased during the day period,and reached the expression peak after 12 hours.4)The RNA interference(RNAi)strategy was used to knockdown the expression of TaAGL32 genes in wheat.The heading of transgenic wheat plants was delayed for 5 to 7 days under LD condition.The transgenic plants headed,on average,about 3d later than the wild-type plants in the field.These results indicate that TaAGL32 may play a role in regulation of wheat heading time.5)The other agronomic traits of transgenic wheat were also investigated.The plant height of the transgenic lines was significantly lower than that of the wildtype plants.But there are not obvious difference in the number of spikelets and the grain weight.