ARABIDOPSIS SIGNAL-TRANSDUCTION MUTANT DEFECTIVE IN CHEMICALLY AND BIOLOGICALLY INDUCED DISEASE RESISTANCE
ARABIDOPSIS SIGNAL-TRANSDUCTION MUTANT DEFECTIVE IN CHEMICALLY AND BIOLOGICALLY INDUCED DISEASE RESISTANCE
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DOI：
10.1073/pnas.92.14.6602
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发表时间：
1995-07-03
影响因子：
11.1
通讯作者：
RYALS, JA
中科院分区：
文献类型：
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作者：
DELANEY, TP;FRIEDRICH, L;RYALS, JA
植物具有多种抵抗病原体的机制，其中包括诱导系统，如系统性获得性抗性（SAR）， SAR在病原体暴露后被激活，导致水杨酸（SA）的增加，SAR相关基因的高表达，以及对一系列病原体的抗性。利用2,6-二氯异烟酸作为SAR基因表达和病原体抗性的激活剂，开发了突变体筛选，随后进行了对真菌病原体Peronospora parasitica的抗性测定，随后对该筛选的突变体进行了检测，以评估其防御反应。我们在这里描述了一个隐性突变，导致对SAR基因和抗性的化学和生物诱导剂不敏感的表型，这些数据表明存在一个共同的信号通路，将这些不同的刺激偶联诱导SAR基因和抗性。由于其不可诱导的免疫表型，我们称该突变体为nim1，尽管nim1植物对SA没有反应，但它们保留了积累野生型SA水平的能力。此外，nim1植物支持正常不相容的真菌病原体小种生长的能力表明，该途径在基因决定的抗性表达中起作用，这与早期转基因植物分解SA的发现一致。这些结果表明，野生型NlM1基因产物在调节获得性抗性的途径中起作用。位于SA积累的下游和SAR基因诱导和抗性表达的上游。
Plants possess multiple resistance mechanisms that guard against pathogen attack, Among these are inducible systems such as systemic acquired resistance (SAR), SAR is activated by pathogen exposure and leads to an increase in salicylic acid (SA), high-level expression of SAR-related genes, and resistance to a spectrum of pathogens, To identify components of the signal transduction pathways regulating SAR, a mutant screen was developed that uses 2,6-dichloroisonicotinic acid as an activator of SAR gene expression and pathogen resistance, followed by assays for resistance to the fungal pathogen Peronospora parasitica, Mutants from this screen were subsequently examined to assess their defense responses. We describe here a recessive mutation that causes a phenotype of insensitivity to chemical and biological inducers of SAR genes and resistance, These data indicate the existence of a common signaling pathway that couples these diverse stimuli to induction of SAR genes and resistance, Because of its non-inducible immunity phenotype, we call this mutant nim1, Although nim1 plants fail to respond to SA, they retain the ability to accumulate wild-type levels of SA, a probable endogenous signal for SAR, Further, the ability of nim1 plants to support growth of normally incompatible races of a fungal pathogen indicates a role for this pathway in expression of genetically determined resistance, consistent with earlier findings for transgenic plants engineered to break down SA, These results suggest that the wild-type NlM1 gene product functions in a pathway regulating acquired resistance, at a position downstream of SA accumulation and upstream of SAR gene induction and expression of resistance.