The Arabidopsis hrl1 mutation reveals novel overlapping roles for salicylic acid, jasmonic acid and ethylene signalling in cell death and defence against pathogens
The Arabidopsis hrl1 mutation reveals novel overlapping roles for salicylic acid, jasmonic acid and ethylene signalling in cell death and defence against pathogens
复制标题
DOI：
10.1046/j.1365-313x.2002.01300.x
复制
发表时间：
2002-05-01
期刊：
影响因子：
7.2
通讯作者：
Raina, R
中科院分区：
文献类型：
--
作者：
Devadas, SK;Enyedi, A;Raina, R
拟南芥对病原体的防御至少由三种信号分子协调：水杨酸（SA）、茉莉酸（JA）和乙烯（ET）。拟南芥的hrl1（过敏反应样病变1）突变体的特征在于自发性坏死病变、活性氧的积累、SA-和ET/JA-反应性防御基因的组成型表达以及对剧毒细菌和卵菌病原体的抵抗力增强。 hrl1与npr1、etr1、coi1和SA耗尽的nahG植物的上位性分析揭示了SA和ET/JA信号通路在调节防御基因表达和细胞死亡方面的新相互作用。对从hrl1双突变体的病灶(+)和病灶(-)叶中分离的RNA进行RNA凝胶印迹分析，揭示了这些组织中防御基因表达的不同信号传导要求。 ET/JA 响应性 PDF1.2 基因的表达在 hrl1 npr1 和 SA 耗尽的 hrl1 nahG 植物中显着降低。在hrl1 nahG植物中，PDF1.2的表达受到苯并噻二唑的浓度依赖性调节：低浓度诱导，高浓度抑制。 hrl1 etr1 植物缺乏系统性 PR-1 表达，并且表现出对剧毒丁香假单胞菌和寄生霜霉的抗性受损。抑制 hrl1 coi1 植物中的 JA 反应会导致细胞过度死亡和植物严重发育迟缓。最后，hrl1 突变导致 AtrbohD 表达升高，AtrbohD 编码 NADPH 氧化酶复合物的一个主要亚基。我们的结果表明，hrl1 中防御基因的表达和对病原体的抵抗力受到 SA 和 ET/JA 防御途径的协同调节。
Defence against pathogens in Arabidopsis is orchestrated by at least three signalling molecules: salicylic acid (SA), jasmonic acid (JA) and ethylene (ET). The hrl1 (hypersensitive response-like lesions 1 ) mutant of Arabidopsis is characterized by spontaneous necrotic lesions, accumulation of reactive oxygen species, constitutive expression of SA- and ET/JA-responsive defence genes, and enhanced resistance to virulent bacterial and oomycete pathogens. Epistasis analyses of hrl1 with npr1 , etr1, coi1 and SA-depleted nahG plants revealed novel interactions between SA and ET/JA signalling pathways in regulating defence gene expression and cell death. RNA gel-blot analysis of RNA isolated separately from the lesion(+) and the lesion(-) leaves of double mutants of hrl1 revealed different signalling requirements for the expression of defence genes in these tissues. Expression of the ET/JA-responsive PDF1.2 gene was markedly reduced in hrl1 npr1 and in SA-depleted hrl1 nahG plants. In hrl1 nahG plants, expression of PDF1.2 was regulated by benzathiadiazole in a concentration-dependent manner: induced at low concentration and suppressed at high concentration. The hrl1 etr1 plants lacked systemic PR-1 expression, and exhibited compromised resistance to virulent Pseudomonas syringae and Peronospora parasitica . Inhibiting JA responses in hrl1 coi1 plants lead to exaggerated cell death and severe stunting of plants. Finally, the hrl1 mutation lead to elevated expression of AtrbohD , which encodes a major subunit of the NADPH oxidase complex. Our results indicate that defence gene expression and resistance against pathogens in hrl1 is regulated synergistically by SA and ET/JA defence pathways.