HY5通过PIF4基因控制高温诱导的拟南芥下胚轴伸长反应

Hypocotyl Elongation of Arabidopsis under High Temperature Condition through PIF4 Gene Control Regulated by HY5

考察了拟南芥野生型、hy5、pif4及hy5pif4双突变体在22℃和30℃培养下的下胚轴伸长表型;利用q RT-PCR监测PIF4基因在野生型和hy5突变体30℃处理后持续多个时间点的动态表达。结果表明,HY5通过抑制下游基因PIF4调控高温诱导的下胚轴伸长。PIF4::GUS启动子融合报告基因株系的染色结果表明,高温对PIF4转录水平的诱导主要发生在子叶而不是下胚轴。通过q RT-PCR检测PIF4同源基因PIF5,生长素合成基因YUC2、YUC3、YUC8和生长素反应基因IAA29在野生型和hy5突变体的动态表达,HY5通过调控PIF4介导的生长素通路来控制拟南芥下胚轴的伸长反应。

Hypocotyl phenotype of wild type,hy5,pif4 and hy5pif4 were examined under 22 ℃ and 30 ℃. q RT-PCR was performed to compare PIF4 expression dynamics during the time course after heat treatment in wild type and hy5 mutant. The expression level of PIF4 was increased in hy5 mutant,suggesting that HY5 repress PIF4 to regulate hypocotyl elongation. Tissue level analysis of PIF4：：GUS promoter reporter indicates that high temperature induced expression of PIF4 occurred in cotyledon but not hypocotyl. Moreover,PIF4 homolog gene PIF5,auxin synthesis genes YUC2,YUC3,YUC8,and auxin response gene IAA29 were upregulated in hy5 mutant when compare to wild type during the time course after high temperature treatment. These suggest HY5 regulate PIF4 mediated auxin pathway to control hypocotyl elongation under high temperature condition.