Pornsiriwong Wannarat, Estavillo Gonzalo M, Chan Kai Xun, Tee Estee E, Ganguly Diep, Crisp Peter A, Phua Su Yin, Zhao Chenchen, Qiu Jiaen, Park Jiyoung, Yong Miing Tiem, Nisar Nazia, Yadav Arun Kumar, Schwessinger Benjamin, Rathjen John, Cazzonelli Christopher I, Wilson Philippa B, Gilliham Matthew, Chen Zhong-Hua, Pogson Barry J
ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Acton, Australia.
Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand.
Elife. 2017 Mar 21;6:e23361. doi: 10.7554/eLife.23361.
Organelle-nuclear retrograde signaling regulates gene expression, but its roles in specialized cells and integration with hormonal signaling remain enigmatic. Here we show that the SAL1-PAP (3'-phosphoadenosine 5'- phosphate) retrograde pathway interacts with abscisic acid (ABA) signaling to regulate stomatal closure and seed germination in . Genetically or exogenously manipulating PAP bypasses the canonical signaling components ABA Insensitive 1 (ABI1) and Open Stomata 1 (OST1); priming an alternative pathway that restores ABA-responsive gene expression, ROS bursts, ion channel function, stomatal closure and drought tolerance in -2. PAP also inhibits wild type and -1 seed germination by enhancing ABA sensitivity. PAP-XRN signaling interacts with ABA, ROS and Ca; up-regulating multiple ABA signaling components, including lowly-expressed Calcium Dependent Protein Kinases (CDPKs) capable of activating the anion channel SLAC1. Thus, PAP exhibits many secondary messenger attributes and exemplifies how retrograde signals can have broader roles in hormone signaling, allowing chloroplasts to fine-tune physiological responses.
细胞器-细胞核逆行信号传导调节基因表达，但其在特化细胞中的作用以及与激素信号传导的整合仍不清楚。在这里，我们表明SAL1-PAP（3'-磷酸腺苷5'-磷酸）逆行途径与脱落酸（ABA）信号传导相互作用，以调节气孔关闭和种子萌发。通过遗传或外源操作PAP绕过了经典信号传导成分ABA不敏感1（ABI1）和开放气孔1（OST1）；启动了一条替代途径，该途径恢复了ABA响应基因表达、ROS爆发、离子通道功能、气孔关闭和耐旱性。PAP还通过增强ABA敏感性来抑制野生型和种子萌发。PAP-XRN信号传导与ABA、ROS和Ca相互作用；上调多种ABA信号传导成分，包括能够激活阴离子通道SLAC1的低表达钙依赖性蛋白激酶（CDPK）。因此，PAP表现出许多第二信使属性，并例证了逆行信号如何在激素信号传导中发挥更广泛的作用，使叶绿体能够微调生理反应。
