The Preliminary Study On Molecular Mechanisms Of GIS Family Genes In Controlling Flowering Time In Arabidopsis Thaliana

Flowering transformation process of plants is affected by the plant’s own genetic factors as well as external environmental factors. It is controlled by flowering genes which express sequentially in time and space that results in this process. Currently, it is known that there are five main pathways that regulate flowering in Arabidopsis. They are listed as photoperiod pathway, autonomous pathway, vernalization pathway, gibberellins and flowering suppress ion pathway. So far, photoperiod pathway is the one that we study the most clearly and relatively completely in comparsion to the other flowering pathways. In this study, we found out that GIS family gene regulate flowering time in Arabidopsis. The rosette leaf number of gisgis2 and zfp8gisgis2 mutants was 3 less than the wild-type in average and these two mutants were flowering earlier than the wild-type. amiZFP5ZFP6GIS3-gisgis2 line flowers much earlier than wild-type too. It bolted in 20 days after germination. The resutls from gene expression analyses had shown that mutation of GIS or GIS2 gene resulted in the increase the exprssion of GI gene. GIS or GIS2 gene may act upstream of the GI gene and plays a key role in controling flowering time through photoperiod pathway. GIS or GIS2 gene suppresses the expression of GI gene. Overexpression of GIS or GIS2 delayed flowering time. CO gene may have feedback inhibition on GIS or GIS2 gene.The resutls from gene expression analyses had shown that ZFP6 or GIS3 gene may also act upstraem of the flowering pathway to control flowering in. Arabidopsis. ZFP6 and GIS3 gene significantly inhibited the expressions of GI, CO, FT genes which function in photoperiod flowering pathway and SOC1, LFY, AGL24 gene which act in the downstream of flowering pathway. In contrast, the mutat of ZFP6 gene significantly increase the expressions of SVP gene which negative regulate flowering time in Arabidopsis. ZFP6 or GIS3 gene may controls flowering time by promoting the expressions of downstream genes in Arabidopsis. Suppression of GIS, GIS2, ZFP5, ZFP6 and GIS3 in amiZFP5ZFP6GIS3-gisgis2 line resulted in significant increase the expression of FT and SOC1 gene.