Study On Expression And Regulation Of The Homologous Gene(OsSEX1) Of Starch Degradation In Rice Leaves

It is close between SEX1 and the degradation of starch in plant.SEX1 protein functions as an overall regulator of starch mobilization by controlling the phosphate content of starch,sex1 mutants could accumulate excessive starch in Arabidopsis thaliana leaves..The SEX1 transcription was influenced by the circadian rhythms of the plant.But there is no report about the gene in rice.According to SEX1 sequence of Arabidopsis thaliana,we found two SEX1 homologous in rice genome,namely OsSEX1-1 and OsSEX1-2.In this study,the maintainer line(Yetai B)were used as the experimental material. Semi-quantitative RT-PCR was used to study their expression pattern in different conditions(including in 3 different developmental stages,natural light/dark,continuous dark,continuous light and trehalose-containing medium).In addition,DNA demethylation's effect on their transcriptional expression was studied.5'-end sequences of OsSEX1-1 were amplicated with RACE research.The main results were summarized as follows:1.The transcription of OsSEX1-1 and OsSEX1-2 were under strong circadian control;2.Light was essential for transcription.At 19:00,transcript reached summit while in dark it decreased;3.Both OsSEX1-1 and OsSEX1-2 were inhabited by trehalose in transcription level which might result in excessive starch accumulation in leaves;4.No difference of DNA demethylation was detected either in OsSEX1-1 or in OsSEX1-2;5.The start site of transcription about OsSEX1-1 was 500bp far from our anti-transcription primer.