A constitutive shade-avoidance mutant implicates TIR-NBS-LRR proteins in Arabidopsis photomorphogenic development
A constitutive shade-avoidance mutant implicates TIR-NBS-LRR proteins in Arabidopsis photomorphogenic development
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DOI：
10.1105/tpc.105.038810
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发表时间：
2006-11-01
期刊：
影响因子：
11.6
通讯作者：
Yanovsky, Marcelo J.
中科院分区：
文献类型：
--
作者：
Faigon-Soverna, Ana;Harmon, Franklin G.;Yanovsky, Marcelo J.
在植物中，邻近植物发出的光信号会加速茎的生长和开花，并促使叶片更加直立，这是一种被称为避荫综合征的发育策略。此外，介导避荫反应的光受体突变增强了拟南芥的疾病易感性。在这里，我们描述了拟南芥组成性避荫1 （csa1）突变体，该突变体在没有荫蔽的情况下显示出避荫表型，并增强了细菌病原体的生长。csa1突变体在Toll/白介素1受体-核苷酸结合位点-富含亮氨酸重复序列（TIR-NBS-LRR）基因的第二外显子内插入T-DNA，导致mRNA被截断。经截断的TIR-NBS-LRR基因转化的拟南芥植株再现了突变表型，表明csa1是一个干扰光敏色素信号传导的显性负突变。TIR-NBS-LRR蛋白参与植物的防御反应。RPS4是与CSA1最接近的同源物，赋予了对丁香假单胞菌的抗性，并补充了CSA1突变表型，表明拟南芥对病原体和邻居的反应共享核心信号成分。在黑腹果蝇和秀丽隐杆线虫中，TIR结构域蛋白与发育和免疫都有关系。因此，TIR结构域的双重作用是跨王国保守的。
In plants, light signals caused by the presence of neighbors accelerate stem growth and flowering and induce a more erect position of the leaves, a developmental strategy known as shade-avoidance syndrome. In addition, mutations in the photo-receptors that mediate shade-avoidance responses enhance disease susceptibility in Arabidopsis thaliana. Here, we describe the Arabidopsis constitutive shade-avoidance1 (csa1) mutant, which shows a shade-avoidance phenotype in the absence of shade and enhanced growth of a bacterial pathogen. The csa1 mutant has a T-DNA inserted within the second exon of a Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR) gene, which leads to the production of a truncated mRNA. Arabidopsis plants transformed with the truncated TIR-NBS-LRR gene recapitulate the mutant phenotype, indicating that csa1 is a dominant-negative mutation that interferes with phytochrome signaling. TIR-NBS-LRR proteins have been implicated in defense responses in plants. RPS4, the closest homolog of CSA1, confers resistance to Pseudomonas syringae and complements the csa1 mutant phenotype, indicating that responses to pathogens and neighbors share core-signaling components in Arabidopsis. In Drosophila melanogaster and Caenorhabditis elegans, TIR domain proteins are implicated in both development and immunity. Thus, the dual role of the TIR domain is conserved across kingdoms.