Zhang Lisha, Kars Ilona, Essenstam Bert, Liebrand Thomas W H, Wagemakers Lia, Elberse Joyce, Tagkalaki Panagiota, Tjoitang Devlin, van den Ackerveken Guido, van Kan Jan A L
Wageningen University, Laboratory of Phytopathology, 6708 PB, Wageningen, The Netherlands.
Plant Physiol. 2014 Jan;164(1):352-64. doi: 10.1104/pp.113.230698. Epub 2013 Nov 20.
Plants perceive microbial invaders using pattern recognition receptors that recognize microbe-associated molecular patterns. In this study, we identified RESPONSIVENESS TO BOTRYTIS POLYGALACTURONASES1 (RBPG1), an Arabidopsis (Arabidopsis thaliana) leucine-rich repeat receptor-like protein, AtRLP42, that recognizes fungal endopolygalacturonases (PGs) and acts as a novel microbe-associated molecular pattern receptor. RBPG1 recognizes several PGs from the plant pathogen Botrytis cinerea as well as one from the saprotroph Aspergillus niger. Infiltration of B. cinerea PGs into Arabidopsis accession Columbia induced a necrotic response, whereas accession Brno (Br-0) showed no symptoms. A map-based cloning strategy, combined with comparative and functional genomics, led to the identification of the Columbia RBPG1 gene and showed that this gene is essential for the responsiveness of Arabidopsis to the PGs. Transformation of RBPG1 into accession Br-0 resulted in a gain of PG responsiveness. Transgenic Br-0 plants expressing RBPG1 were equally susceptible as the recipient Br-0 to the necrotroph B. cinerea and to the biotroph Hyaloperonospora arabidopsidis. Pretreating leaves of the transgenic plants with a PG resulted in increased resistance to H. arabidopsidis. Coimmunoprecipitation experiments demonstrated that RBPG1 and PG form a complex in Nicotiana benthamiana, which also involves the Arabidopsis leucine-rich repeat receptor-like protein SOBIR1 (for SUPPRESSOR OF BIR1). sobir1 mutant plants did not induce necrosis in response to PGs and were compromised in PG-induced resistance to H. arabidopsidis.
植物利用模式识别受体来感知微生物入侵者，这些受体能够识别微生物相关分子模式。在本研究中，我们鉴定出了对葡萄孢多聚半乳糖醛酸酶1（RBPG1）有响应，它是拟南芥（Arabidopsis thaliana）中一种富含亮氨酸重复序列的受体样蛋白AtRLP42，能够识别真菌内切多聚半乳糖醛酸酶（PGs），并作为一种新型的微生物相关分子模式受体发挥作用。RBPG1能够识别来自植物病原菌灰葡萄孢（Botrytis cinerea）的几种PGs以及来自腐生菌黑曲霉（Aspergillus niger）的一种PG。将灰葡萄孢PGs浸润到拟南芥生态型哥伦比亚中会诱导坏死反应，而生态型布尔诺（Br-0）则没有症状。基于图谱的克隆策略，结合比较基因组学和功能基因组学，导致了哥伦比亚RBPG1基因的鉴定，并表明该基因对于拟南芥对PGs的响应至关重要。将RBPG1转化到Br-0生态型中导致了对PGs响应性的增加。表达RBPG1的转基因Br-0植物与受体Br-0对坏死营养型灰葡萄孢和活体营养型阿拉伯假霜霉（Hyaloperonospora arabidopsidis）同样敏感。用PG预处理转基因植物的叶片会导致对阿拉伯假霜霉的抗性增加。免疫共沉淀实验表明，RBPG1和PG在本氏烟草（Nicotiana benthamiana）中形成复合物，这也涉及拟南芥富含亮氨酸重复序列的受体样蛋白SOBIR1（BIR1的抑制子）。sobir1突变体植物对PGs不诱导坏死反应，并且在PG诱导的对阿拉伯假霜霉的抗性方面存在缺陷。
