Plant hormone jasmonate prioritizes defense over growth by interfering with gibberellin signaling cascade
Plant hormone jasmonate prioritizes defense over growth by interfering with gibberellin signaling cascade
复制标题
植物激素茉莉酸通过干扰赤霉素信号级联将防御置于生长之上
DOI：
10.1073/pnas.1201616109
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发表时间：
2012-05-08
影响因子：
11.1
通讯作者：
He, Sheng Yang
中科院分区：
文献类型：
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作者：
Yang, Dong-Lei;Yao, Jian;He, Sheng Yang
植物必须有效地抵御生物和非生物胁迫才能在自然界中生存。然而，这种防御是昂贵的，往往伴随着显着的生长抑制。植物如何协调波动的生长-防御动力学还没有很好地理解，仍然是一个基本问题。茉莉酸（JA）和赤霉素（GA）是植物中重要的激素，分别调节植物的防御和生长。生物活性JA或GA配体与同源受体的结合导致特异性转录阻遏物（JAZ或DELLA蛋白家族）的蛋白酶体依赖性降解，其在静息状态下阻遏参与防御的同源转录因子（例如，MYC）或生长[例如光敏色素相互作用因子（PIF）]。在这项研究中，我们发现，水稻（一种驯化的单子叶作物）和拟南芥（一种模式双子叶植物）的coi 1 JA受体突变体都表现出GA过敏突变体的标志表型。JA延迟GA介导的DELLA蛋白降解，并且DELLA突变体对JA的生长抑制不太敏感。在拟南芥植物中过表达一组选定的JAZ阻遏物部分表型复制GA相关的表型的coi 1突变体，和JAZ 9抑制RGA（DELLA蛋白）与转录因子PIF 3的相互作用。重要的是，pifq突变体不再响应于JA诱导的生长抑制，PIF 3的过表达可以部分克服JA诱导的生长抑制。因此，已经阐明了涉及COI 1-JAZ-DELLA-PIF信号传导模块的分子级联，被子植物通过该分子级联优先考虑JA介导的防御而不是生长。
Plants must effectively defend against biotic and abiotic stresses to survive in nature. However, this defense is costly and is often accompanied by significant growth inhibition. How plants coordinate the fluctuating growth-defense dynamics is not well understood and remains a fundamental question. Jasmonate (JA) and gibberellic acid (GA) are important plant hormones that mediate defense and growth, respectively. Binding of bioactive JA or GA ligands to cognate receptors leads to proteasome-dependent degradation of specific transcriptional repressors (the JAZ or DELLA family of proteins), which, at the resting state, represses cognate transcription factors involved in defense (e.g., MYCs) or growth [e.g. phytochrome interacting factors (PIFs)]. In this study, we found that the coi1 JA receptor mutants of rice (a domesticated monocot crop) and Arabidopsis (a model dicot plant) both exhibit hallmark phenotypes of GA-hypersensitive mutants. JA delays GA-mediated DELLA protein degradation, and the della mutant is less sensitive to JA for growth inhibition. Overexpression of a selected group of JAZ repressors in Arabidopsis plants partially phenocopies GA-associated phenotypes of the coi1 mutant, and JAZ9 inhibits RGA (a DELLA protein) interaction with transcription factor PIF3. Importantly, the pif quadruple (pifq) mutant no longer responds to JA-induced growth inhibition, and overexpression of PIF3 could partially overcome JA-induced growth inhibition. Thus, a molecular cascade involving the COI1–JAZ–DELLA–PIF signaling module, by which angiosperm plants prioritize JA-mediated defense over growth, has been elucidated.