Godiard Laurence, Sauviac Laurent, Torii Keiko U, Grenon Olivier, Mangin Brigitte, Grimsley Nigel H, Marco Yves
Laboratoire des Interactions Plantes-Microorganismes, CNRS-INRA, B.P. 27, 31326 Castanet-Tolosan, France.
Plant J. 2003 Nov;36(3):353-65. doi: 10.1046/j.1365-313x.2003.01877.x.
Bacterial wilt, one of the most devastating bacterial diseases of plants worldwide, is caused by Ralstonia solanacearum and affects many important crop species. We show that several strains isolated from solanaceous crops in Europe are pathogenic in different accessions of Arabidopsis thaliana. One of these strains, 14.25, causes wilting symptoms in A. thaliana accession Landsberg erecta (Ler) and no apparent symptoms in accession Columbia (Col-0). Disease development and bacterial multiplication in the susceptible Ler accession depend on functional hypersensitive response and pathogenicity (hrp) genes, key elements for bacterial pathogenicity. Genetic analysis using Ler x Col-0 recombinant inbred lines showed that resistance is governed by at least three loci: QRS1 (Quantitative Resistance to R. solanacearum) and QRS2 on chromosome 2, and QRS3 on chromosome 5. These loci explain about 90% of the resistance carried by the Col-0 accession. The ERECTA gene, which encodes a leucine-rich repeat receptor-like kinase (LRR-RLK) and affects development of aerial organs, is dimorphic in our population and lies close to QRS1. Susceptible Ler plants transformed with a wild-type ERECTA gene, and the LER line showed increased disease resistance to R. solanacearum as indicated by reduced wilt symptoms and impaired bacterial growth, suggesting unexpected cross-talk between resistance and developmental pathways.
青枯病是全球最具毁灭性的植物细菌性病害之一，由青枯雷尔氏菌引起，影响许多重要的作物品种。我们发现，从欧洲茄科作物中分离出的几个菌株对不同拟南芥种质具有致病性。其中一个菌株14.25，在拟南芥种质Landsberg erecta（Ler）中引起萎蔫症状，而在Columbia（Col-0）种质中未引起明显症状。在易感的Ler种质中，病害发展和细菌繁殖依赖于功能性过敏反应和致病性（hrp）基因，这是细菌致病性的关键要素。利用Ler×Col-0重组自交系进行的遗传分析表明，抗性由至少三个位点控制：位于2号染色体上的QRS1（对青枯雷尔氏菌的数量抗性）和QRS2，以及位于5号染色体上的QRS3。这些位点解释了Col-0种质所携带抗性的约90%。ERECTA基因编码一种富含亮氨酸重复序列的类受体激酶（LRR-RLK），影响地上器官的发育，在我们的群体中呈二态性，且位于QRS1附近。用野生型ERECTA基因转化的易感Ler植株，以及LER品系对青枯雷尔氏菌的抗病性增强，表现为萎蔫症状减轻和细菌生长受抑制，这表明抗性和发育途径之间存在意想不到的相互作用。
