Structure And Function Analysis Of Cotton R2R3-MYB And Functional Prediction Of Three MYB Transcription Factors In Cotton

Cotton is one of the most important economic crops in the world.In recent years,more and more studies of genes regulating the cotton fiber development were reported.MYB transcription factor family is one of the largest families of transcription factors in plants,which play an important role in stress tolerance and hormone response in maize and Arabidopsis.In cotton,some study also showed that the MYB family involved in regulating the cotton fiber development.In this study,three MYB genes Gh_A12G1309,Gh_D12G1202 and Gh_A12G2460 were selected for functional analysis,which showed significantly high expression in cotton fiber initiation,fast elongation,and secondary wall biosynthesis.The R2R3 domain was blasted agaist to the TM-1 reference genome,a total of 34 homologous genes were screened including above three genes.According to the C-sequence mutability,we analyzed the genes subfamily,amino acid conservative sequences and genetic informationand and divided them into four subfamilies.However,nine remaining genes were not classified into the any subfamily.Based on the analysis of gene sequence and amino acid sequence,and the function of homologous genes in other species such as Arabidopsis and Maize,the function of each subfamily has been studied and predicted.The expression patterns of these 34 genes in 35 distinct tissues of cotton were also different.We constructed the expression vector pBI1Z1 and pBIN-GFP4 and transfered the studied genes into Arabidopsis thaliana Col-0 as transgenie receptor.The function of the genes was determined by observing the changes of characters and physiological and biochemical experiments.No visible phenotypic changes were observed in transgenic Arabidopsis thaliana with Gh_A12G1309 or Gh_D12G1202.The phenotypes of rosette leaves short and reproductive growth in advance were found in 28 individuals of T2 transgenic Arabidopsis with Gh_A12G2460,indicating that the gene may improve vegetative growth to reproductive growth,or may be involved in the regulation of plant height.