Isolation And Functional Analysis Of TaMOC1 In Triticum Aestivum L.

Wheat(Triticum aestivum L.)is one of the most widely grown crops for food.Improving yields of wheat is very necessary to feed the increasing human population.Branching(tillering)is one of the most important agronomic traits,which directly affects crop yield,spike number is a very important factor affecting wheat yields,which is determined by the number of effective tiller.Therefore it is very important to understand the molecular mechanism of tillering.Previous researches showed that MOC1 could not only controls the initiation of axillary meristem and formation of tiller buds,but also promotes tiller growth in rice(Oryza sativa L.).To understand the molecular mechanism of tillering in wheat,we isolated TaMOC1 and studied its expression pattern and function.The results are as follows:There are three alleles of TaMOC1,which were assigned to wheat chromosome 7A,7B and 7D,respectively.Three homoeolgs are highly similar(about 97.71%)to each other.The full length of TaMOC1 cDNAs are 1290bp(TaMOC1-7A),1281bp(TaMOC1-7B)and 1278bp(TaMOC1-7D)respectively,which encode 430,427 and 426 amino acids.The gDNA contains only one exon.Phylogenetic tree analysis showed that TaMOC1-7B had a close genetic relationship with LAS1 in barley(Hordeum vulgare L.),so we selected 1281bp(TaMOC1-7B)as the research object.TaMOC1 protein is located in the nucleus by subcellular localization.Quantitative PCR analysis showed that TaMOC1 was expressed mainly in shoot apex,axillary buds and spikelets of wheat,but lower in young leaves and young roots.RNA in situ hybridization showed that the TaMOC1 expression was detected in the epidermal cells of leaf primordia,subsequently lasted to the axillary buds,SAM and young leaves.In addition,the signals could also be detected in spike primordia.To confirm the function of TaMOC1 in wheat,the TaMOC1 RNA interference(RNAi)and overexpression vectors were transfected into wheat(cultivated variety KN199).A total of 13 independent TaMOC1-RNAi transgenic lines and 14 independent TaMOC1-OX transgenic lines were obtained.Further analysis showed that the total tiller numbers of T3 generation TaMOC1-RNAi transgenic line M6-5,M37-2 and M41-5 were reduced,compared with KN199 at pre-overwintering stage and jointing stage.The expression levels of TaMOC1 in M6-5,M37-2 and M41-5 lines were also decreased than that in KN199,which suggested that TaMOC1 might be involved in the regulation of wheat tillering.Now,further phenotypic analysis is performed.In conclusion,TaMOC1 may play an important role in the regulation of wheat tillering.Ours results will provide new insights for understanding the mechanism of tillering in plants.