Functional Analysis Of A MYB Transcription Factor TF865 In Regulation Of Rice Height

Rice(Oryza sativa L.) is one of the most important staple crops in China and around the world, feeding more than half the world’s population, and it is also an important model plant for gene function research. Investigators have made great progresses associated with rice genetics and molecular biology and revealed that the regulation of transcription is one of the major layers orchestrating gene expression. Plant MYB transcription factor(TF) family is comprised of a large number TFs which involved in the regulation of many physiological processes including plant development, metabolism and response to biotic and abiotic stress and so on. In this study, we cloned the CDS of a MYB family gene TF865 using the rice Nipponbare c DNA as template. Furthermore, we constructed expression vectors in which TF865 was fused the transcriptional activation motif VP64(CV865) or the transcriptional suppressor motif EAR(CE865) using GATEWAY SYSTEM, respectively. Through genetic transformation, we obtained multiple independent transgenic plants in Kita-ake cultivar background. Via the investigations of CV865 and CE865 transgenic plants, we obtained following observations or conclusions:1. The plant height of CV865 is decreased while CE856 is increased in comparison to WT control at both three-leaf stage and mature stage, indicating that TF865 is possibly involved in the regulation of plant height. Longitudinal anatomical slices of internode observed that the cell number of transgenic materials and WT control did not change significantly, but the length of the cells changed significantly, indicating that TF865 transcription factors is possibly involved in the regulation of cell elongation.2. CV865 showed no obvious effect on plant heading time, but CE865 significantly delayed heading time for about one month; Although the tiller numbers of both CV865 and CE865 transgenic plants were decreased, the primary branch number of CE865 plants significantly increased. Therefore, CE865 transgenic plants perform better than WT control in the aspect of yield per plant.3. The expression profiles in CV865, CE865 transgenic plants were investigated in comparison to that of WT control. The results indicated that: 778up-regulated genes were significantly changed in CV865; 1668 down-regulated genes were significantly changed in CE865; Overlapping analysis revealed that 86 genes were up-regulated in CV865 plants but down-regulated in CE865 plants. So among these genes,there may be downstream regulated genes of TF865 transcription factor genes.