Apoplastic Reactive Oxygen Species Transiently Decrease Auxin Signaling and Cause Stress-Induced Morphogenic Response in Arabidopsis
Apoplastic Reactive Oxygen Species Transiently Decrease Auxin Signaling and Cause Stress-Induced Morphogenic Response in Arabidopsis
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DOI：
10.1104/pp.111.181883
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发表时间：
2011-12-01
期刊：
影响因子：
7.4
通讯作者：
Kangasjarvi, Jaakko
中科院分区：
文献类型：
--
作者：
Blomster, Tiina;Salojarvi, Jarkko;Kangasjarvi, Jaakko
活性氧(ROS)是植物逆境和发育过程中普遍存在的信号分子。为了进一步了解植物对质外体ROS的转录反应，以植物毒性大气污染物臭氧为模型ROS诱导剂，利用基因芯片分析了拟南芥的基因表达。与通过胁迫激素水杨酸、脱落酸、茉莉酸(JA)和乙烯诱导的信号转导增强相反，ROS处理导致生长素信号转导被暂时抑制，这在DR5-uidA生长素报告结构中得到了证实。转录数据显示，质外体ROS改变了生长素动态平衡和信号转导的各个方面。此外，对生长素信号的详细分析表明，一些生长素受体和生长素/吲哚-3-乙酸(AUX/IAA)转录抑制因子的转录水平在质外体ROS的响应下降低。ROS引起的生长素信号基因表达的变化与非生物胁迫、病原菌反应和水杨酸信号部分重叠。已知的在生物胁迫中抑制生长素信号的几种机制被排除在外，这表明ROS通过一种新的机制调节生长素反应。利用不同生长素(AxR1、Nit1、Aux1、TIR1afb2、iaa28-1、iaa28-2)和JA(AxR1、coi1-16)反应缺陷的突变体，发现ROS诱导的细胞死亡受JA调节，但不受生长素调节。长期的ROS处理导致了叶片形态的改变，这种胁迫反应被称为“胁迫诱导的形态发生反应”。TIR1afb2的叶形变化表明生长素是胁迫诱导的莲座丛形态发生反应的负调节因子。
Reactive oxygen species (ROS) are ubiquitous signaling molecules in plant stress and development. To gain further insight into the plant transcriptional response to apoplastic ROS, the phytotoxic atmospheric pollutant ozone was used as a model ROS inducer in Arabidopsis (Arabidopsis thaliana) and gene expression was analyzed with microarrays. In contrast to the increase in signaling via the stress hormones salicylic acid, abscisic acid, jasmonic acid (JA), and ethylene, ROS treatment caused auxin signaling to be transiently suppressed, which was confirmed with a DR5-uidA auxin reporter construct. Transcriptomic data revealed that various aspects of auxin homeostasis and signaling were modified by apoplastic ROS. Furthermore, a detailed analysis of auxin signaling showed that transcripts of several auxin receptors and Auxin/Indole-3-Acetic Acid (Aux/IAA) transcriptional repressors were reduced in response to apoplastic ROS. The ROS-derived changes in the expression of auxin signaling genes partially overlapped with abiotic stress, pathogen responses, and salicylic acid signaling. Several mechanisms known to suppress auxin signaling during biotic stress were excluded, indicating that ROS regulated auxin responses via a novel mechanism. Using mutants defective in various auxin (axr1, nit1, aux1, tir1 afb2, iaa28-1, iaa28-2) and JA (axr1, coi1-16) responses, ROS-induced cell death was found to be regulated by JA but not by auxin. Chronic ROS treatment resulted in altered leaf morphology, a stress response known as "stress-induced morphogenic response." Altered leaf shape of tir1 afb2 suggests that auxin was a negative regulator of stress-induced morphogenic response in the rosette.