一个水稻叶片衰老上调表达基因的初步生物学功能分析

叶片衰老是其发育的最后阶段。通过对水稻叶片衰老机制的研究, 有计划地控制或延缓衰老的发生具有重要的理论价值和实践意义。本研究基于基因表达芯片数据挑选了一个叶片衰老上调表达候选基因A12 (LOC_Os 07g41230)。A12基因在水稻全生育期表达谱数据库中的表达模式及在水稻抽穗后不同时期剑叶中的表达量检测结果进一步证明其确为叶片衰老上调表达基因。生物信息学预测A12基因启动子区域存在大量的与激素诱导相关的顺式作用元件。实时定量PCR结果显示A12基因对茉莉酸(JA)和激动素(KT)的诱导有明显的响应, 但是对油菜素内酯(BR)、赤霉素(GA)、生长素(IAA)及脱落酸(ABA)的诱导则无明显响应。对A12基因对应的水稻T-DNA插入突变体观察发现, A12基因的突变会导致剑叶早衰。这些结果为进一步深入研究A12基因的生物学功能打下了基础。

Preliminary Functional Analysis of a Rice Leaf Senescence Up-Regulated Gene

Leaf senescence is the last stage in leaf development. It has important theoretical and practical significance to study the mechanism on rice leaf senescence and the find out a way to purposefully control or delay leaf senececne. In this study, we identified a rice leaf senescence up-regulated gene A12 (LOC_Os 12g33120) according to the leaf senescence gene expression microarray data. The analysis from the rice gene expression profile database in whole growth period and qRT-PCR result of A12 expression in flag leaves at different stages after heading further confirmed that A12 was a leaf senescence up-regulated gene. Bioinformatic analysis found many phytohormone-responsive cis-acting elements in A12 promoter. Quantitative real-time PCR analysis indicated the A12 gene were up-regulated by JA and KT treatments, but not apparently induced by BR, GA, IAA, and ABA. Research on the rice T-DNA insertion mutant of A12 found that loss of function of this gene led to premature senescence of flag leaf. These results lay a foundation for the further functional analysis of this gene.