Phenotypes Analysis Of Synthetic Transcription Factor VP-OsIAA26 In Rice(Oryza Sativa)

Rice is an important food crop, It is crucialto optimize the rice plant type and improve the yield to meet world food securityneeds. Plant hormones which are synthesised in vivo transported to target site and regulate growth and development of plant. Even in low concentration plant hormones act efficiently through signal transduction and regulates variety of genes expression. The earliest discovered plant hormone is auxin(IAA). Previous findings shows that auxin can regulate many mechanisms, including apical dominance,nutrient transportation tropic growth, cell division, vascular bundle differentiation, expansion of leaf blade, stem elongation,falling of flowers, growing branch, and preventing leaves from senility. Hence, the auxin is important to regulate growth and development.Auxin regulates auxin responsive genesexpression. So we can research auxin responsive genes to batter understand it’s function. The auxin response genes can be divided into two types, primary response gene and secondary response genes. The primary response genes are further divided into three types: Aux/IAA( auxin/indoleacetic acid), GH3( Gretchen Hagen3) and SAUR( small auxin-up RNA). Primary genes could be activated by transcription factors that already exists,socrops can response exogenous auxin quickly. Generally, these primary response genes have auxin response element(Aux RE) in promoters, auxin response factor( ARF) can bind Aux RE and regulates genes’ expression.There are 31 Os IAA genes in rice Aux/IAA genes family. IAA is the short-lived protein that located in nucleus. IAA plays role as repressive factor in regulating genes expression. In this study, we construct Os IAA26 fusion 4*VP16 and get a synthetic transcription factor VP- Os IAA26. When compared with wild type(Kita-ate), we found that:(1) Transgenic VP-Os IAA26 rice shows late flowering phenotype under either SD( short day,10 h light under 28℃/14 h dark under 24℃), LD( long day, 14 hlight under 28℃/10 h dark under 24℃), or ND( nature day, from April to September in2015, the place is experiment base construction of Chinese academy of agricultural sciences, 39 °54’N,116°23’E).(2) Compare with WT, tansgenic VP-Os IAA26 rice shows many different in agronomic characrers,such as, tansgenic VP-Os IAA26 rice is higher than WT, and the panicle of tansgenic VP-Os IAA26 rice is higher than WT’s,the grain number per plant of tansgenic VP-Os IAA26 rice is more than WT’s, grain yield per plant of tansgenic VP-Os IAA26 rice is heavier than that of WT.(3) We cultivated the tansgenic VP-Os IAA26 rice and WT under the same condition( SD and LD respectively), and used those plant for RT-PCR.RT-PCR analysis concluded that, the transcriptional level of Hd1 shows no significant different, VP-Os IAA26 affect flowering time through Ehd1 pathway under SD/LD conditions.(4) The result of transactivation activity assays of Os IAA26 and VP-Os IAA26 in the yeast GAL4 system shows that Os IAA26 maybe is a transformation suppressor.(5)By constructing prokaryotic expression vector, we obtained the fusion pritein, Os IAA26-YFP. Through subcellular loczlization analysis,we found Os IAA26 maybe locatedin nucleus and cytomembrane.