Su Mengying, Huang Gan, Zhang Qing, Wang Xiao, Li Chunxin, Tao Yujin, Zhang Shengchun, Lai Jianbin, Yang Chengwei, Wang Yaqin
Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou 510631, PR China.
Plant Sci. 2016 Jun;247:93-103. doi: 10.1016/j.plantsci.2016.03.009. Epub 2016 Mar 24.
The phytohormone abscisic acid (ABA) modulates plant growth and developmental processes such as leaf senescence. In this study, we investigated the role of the Arabidopsis late embryogenesis abundant (LEA) protein ABR (ABA-response protein) in delaying dark-induced leaf senescence. The ABR gene was up-regulated by treatment with ABA, NaCl and mannitol, as well as by light deprivation. In the dark, abr mutant plants displayed a premature leaf senescence phenotype, and various senescence-associated indicators, such as an increase in chlorophyll degradation and membrane leakiness, were enhanced, whereas 35S:ABR/abr transgenic lines showed a marked delay in dark-induced leaf senescence phenotypes. In vitro and in vivo assays showed that ABI5 bind to the ABR promoter, indicating that ABI5 directly regulates the expression of ABR. The disruption of ABI5 function in abr abi5-1 plants abolished the senescence-accelerating phenotype of the abr mutant, demonstrating that ABI5 is epistatic to ABR. In summary, these results highlight the important role that ABR, which is negatively regulated by ABI5, plays in delaying dark-induced leaf senescence.
植物激素脱落酸（ABA）可调节植物生长和发育过程，如叶片衰老。在本研究中，我们探究了拟南芥晚期胚胎丰富（LEA）蛋白ABR（ABA响应蛋白）在延缓黑暗诱导的叶片衰老中的作用。ABA、NaCl和甘露醇处理以及光照剥夺均可上调ABR基因的表达。在黑暗中，abr突变体植株表现出叶片早衰表型，叶绿素降解增加和膜渗漏等各种衰老相关指标增强，而35S:ABR/abr转基因株系在黑暗诱导的叶片衰老表型上表现出明显延迟。体外和体内试验表明，ABI5与ABR启动子结合，表明ABI5直接调控ABR的表达。abr abi5-1植株中ABI5功能的破坏消除了abr突变体的衰老加速表型，表明ABI5对ABR具有上位性。总之，这些结果突出了受ABI5负调控的ABR在延缓黑暗诱导的叶片衰老中所起的重要作用。
