The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance
The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance
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DOI：
10.15252/embj.201487923
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发表时间：
2014-09-01
期刊：
影响因子：
11.4
通讯作者：
Kroj, Thomas
中科院分区：
文献类型：
--
作者：
Cesari, Stella;Kanzaki, Hiroyuki;Kroj, Thomas
植物抗性蛋白是一类核苷酸结合蛋白和富含亮氨酸重复结构域蛋白（nb - lrs），它们是识别病原体来源分子的免疫传感器，称为无毒蛋白（AVR）。我们发现，RGA4和RGA5这两个来自水稻的nb - lrr在功能和物理上相互作用，介导水稻对真菌病原体稻瘟病菌的抗性，并在AVR识别中完成不同的功能。RGA4触发一种与avr无关的细胞死亡，这种死亡在水稻原生质体和烟叶中都受到抑制。通过直接结合RGA5识别病原体效应物AVR-Pia，抑制被解除，细胞发生死亡。RGA4和RGA5形成同质和异质复合物，并通过它们的线圈结构域相互作用。水稻原生质体的定位研究表明，RGA4和RGA5定位于细胞质中。在识别AVR-Pia后，RGA4和RGA5都不会重新定位到细胞核中。这些结果建立了植物中nb - lrs异源对相互作用的模型：RGA4介导细胞死亡激活，而RGA5作为RGA4的抑制因子和AVR受体。
Plant resistance proteins of the class of nucleotide-binding and leucine-rich repeat domain proteins (NB-LRRs) are immune sensors which recognize pathogen-derived molecules termed avirulence (AVR) proteins. We show that RGA4 and RGA5, two NB-LRRs from rice, interact functionally and physically to mediate resistance to the fungal pathogen Magnaporthe oryzae and accomplish different functions in AVR recognition. RGA4 triggers an AVR-independent cell death that is repressed in the presence of RGA5 in both rice protoplasts and Nicotiana benthamiana. Upon recognition of the pathogen effector AVR-Pia by direct binding to RGA5, repression is relieved and cell death occurs. RGA4 and RGA5 form homo-and hetero-complexes and interact through their coiled-coil domains. Localization studies in rice protoplast suggest that RGA4 and RGA5 localize to the cytosol. Upon recognition of AVR-Pia, neither RGA4 nor RGA5 is re-localized to the nucleus. These results establish a model for the interaction of hetero-pairs of NB-LRRs in plants: RGA4 mediates cell death activation, while RGA5 acts as a repressor of RGA4 and as an AVR receptor.