ERECTA receptor-like kinase and heterotrimeric G protein from Arabidopsis are required for resistance to the necrotrophic fungus Plectosphaerella cucumerina
ERECTA receptor-like kinase and heterotrimeric G protein from Arabidopsis are required for resistance to the necrotrophic fungus Plectosphaerella cucumerina
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DOI：
10.1111/j.1365-313x.2005.02440.x
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发表时间：
2005-07-01
期刊：
影响因子：
7.2
通讯作者：
Molina, A
中科院分区：
文献类型：
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作者：
Llorente, F;Alonso-Blanco, C;Molina, A
拟南芥对黄瓜枯萎病菌的抗性是复杂的，依赖于乙烯、茉莉酸和水杨酸的信号转导途径。对两个重组自交系群体进行了抗病数量性状基因座(QTL)分析。在第2染色体(QRP1和QRP2)和第5染色体(ORP3)上定位了3个座位ORP1-QRP3。QRP1基因的作用最强，与ERECTA(ER)基因相对应，该基因编码一种受体样激酶(RLK)，此前已被认为与植物发育有关，并与青枯病菌的抗性有关。ERECTA富含亮氨酸的重复序列和激酶结构域是抗病所必需的，因为在这两个结构域中的任何一个受损的ER突变等位基因都显示出对这种真菌的敏感性增强，但对其他致病病原菌没有影响。编码拟南芥异源三聚体G蛋白P-亚基的3个突变体elk2、elk5和elk4(AgB 1-1)也对黄瓜疫霉的抗性造成了损害，从而支持了ER信号通路在黄瓜疫霉病抗性中的作用。G蛋白α亚基的零等位基因(gpa1-4)对黄瓜疫霉病菌的抗性增强证实了拟南芥异源三聚体G蛋白在对黄瓜疫霉病菌的抗性中所起的作用。接种黄瓜疫霉后，er-1和agb1-1突变体侵染部位的β-1，3-葡聚糖沉积明显受损。综上所述，这些数据表明ERECTA和异源三聚体G蛋白可能在黄瓜疫霉的感知中起作用。
Arabidopsis resistance to the necrotrophic fungus Plectosphaerella cucumerina is complex and depends on the ethylene, jasmonic acid and salicylic acid signaling pathways. A quantitative trait loci (QTL) analysis of resistance to this fungus was performed using two populations of recombinant inbred lines. Three loci ORP1-QRP3 (for Quantitative Resistance to Plectosphaerella) were identified and mapped on chromosome 2 (QRP1 and QRP2) and 5 (ORP3). QRP1, the locus showing the strongest effect, was found to correspond to the ERECTA (ER) gene that encodes a receptor-like-kinase (RLK), which has been previously implicated in plant development, and resistance to the bacterium Ralstonia, solanacearum. The leucine-rich repeat and the kinase domains of ERECTA were specifically required for resistance to A cucumerina, as er mutant alleles impaired in any of these domains showed enhanced susceptibility to this fungus, but not to other virulent pathogens. The involvement of the ER-signaling pathway in resistance to P. cucumerina was supported by the fact that three mutants defective in this pathway, elk2, elk5 and elk4 (agb 1-1), which encodes the P-subunit of Arabidopsis heterotrimeric G protein, were also impaired in their resistance to this fungus. The putative function of the Arabidopsis heterotrimeric G protein in resistance to P. cucumerina suggested by the enhanced susceptibility of agb1-1 was corroborated by the demonstration that a null allele (gpa1-4) of the G protein alpha-subunit showed enhanced resistance to this pathogen. Deposition of beta-1,3-glucan callose at infection sites was specifically impaired in er-1 and agb1-1 mutants upon P. cucumerina inoculation. Taken together, these data suggest a putative function of ERECTA and heterotrimeric G protein in P. cucumerina perception.