Detection and functional characterization of a large genomic deletion resulting in decreased pathogenicity in Ralstonia solanacearum race 3 biovar 2 strains
Detection and functional characterization of a large genomic deletion resulting in decreased pathogenicity in Ralstonia solanacearum race 3 biovar 2 strains
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DOI：
10.1111/j.1462-2920.2011.02636.x
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发表时间：
2011-12-01
影响因子：
5.1
通讯作者：
Genin, Stephane
中科院分区：
文献类型：
--
作者：
Gonzalez, Adriana;Plener, Laure;Genin, Stephane
由青枯菌（Ralstonia solanacearum）引起的马铃薯细菌性枯萎病（brown rot disease）是马铃薯的重要细菌性病害之一，是制约马铃薯生产的主要因素。通过比较基因组学分析，对R.在青枯菌“3号生理小种2”（R3bv2）菌株中，我们鉴定了菌株UW551中的77kb区域，该区域在低侵袭性菌株IPO1609中特异性地缺失。我们证明了IPO1609确实携带一个77 kb的基因组缺失，并提供了遗传学证据，该缺失的发生是该菌株致病性几乎完全丧失的原因。我们进行了一个功能分析，这77 kb的区域在菌株UW551使用的基因缺失和功能互补的方法，确定了蛋氨酸生物合成基因metER作为一个主要的贡献IPO1609发病机制的组合。metER基因的缺失显著影响R3bv2菌株的致病性，但不会导致甲硫氨酸营养缺陷型，也不会降低在植物中繁殖的能力。此外，这项研究表明，三个III型分泌系统效应或VI型分泌系统内存在的77 kb区域内没有或非常小的贡献致病性。
Bacterial wilt (brown rot) disease of potato caused by Ralstonia solanacearum is one of the most important bacterial diseases and a major constraint on potato production worldwide. Through a comparative genomic analysis between R. solanacearum 'race 3 biovar 2' (R3bv2) strains, we identified a 77 kb region in strain UW551 which is specifically absent in the hypoaggressive strain IPO1609. We proved that IPO1609 indeed carries a 77 kb genomic deletion and provide genetic evidence that occurrence of this deletion is responsible for almost complete loss of pathogenicity of this strain. We carried out a functional analysis of this 77 kb region in strain UW551 using a combination of gene deletion and functional complementation approaches which identified the methionine biosynthesis genes metER as having a major contribution to IPO1609 pathogenesis. Deletion of the metER genes significantly impacts pathogenicity of R3bv2 strains but does not lead to methionine auxotrophy nor reduced ability to multiply in planta. In addition, this study indicated that three type III secretion system effectors or a type VI secretion system present within the 77 kb region have no or very minor contribution to pathogenicity.