Genome-Enabled Phylogeographic Investigation of the Quarantine Pathogen Ralstonia solanacearum Race 3 Biovar 2 and Screening for Sources of Resistance Against Its Core Effectors
Genome-Enabled Phylogeographic Investigation of the Quarantine Pathogen Ralstonia solanacearum Race 3 Biovar 2 and Screening for Sources of Resistance Against Its Core Effectors
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DOI：
10.1094/phyto-12-14-0373-r
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发表时间：
2015-05-01
期刊：
影响因子：
3.2
通讯作者：
Vinatzer, Boris A.
中科院分区：
文献类型：
--
作者：
Clarke, Christopher R.;Studholme, David J.;Vinatzer, Boris A.
系统地理学研究提供病原体传播途径的信息，有助于改进进出口管制。因此，分析了17个分离物的基因组的细菌性枯萎病和马铃薯褐腐病病原菌青枯雷尔氏菌生理小种3生物型2（R3bv2），在美国的选择剂，以了解这种病原菌的地理分布。来自欧洲、非洲和亚洲的14株分离株中有13株属于单一克隆谱系，而来自南美洲的分离株遗传多样，在分析的基因组位点上倾向于携带祖先等位基因，这与R3bv2的南美洲起源一致。R3bv2分离株共有31个III型分泌的效应基因的核心库，这些基因代表了在育种计划中用抗性基因靶向的优秀候选基因，以开发持久的抗病性。为了实现这一目标，在茄子、番茄、辣椒、烟草和莴苣中测试了27种R3bv2效应物，以诱导指示由同源抗性受体识别的超敏样应答。15个效应子，其中8个是核心效应子，在一个或多个植物物种中引发了反应。这些基因型可能含有可以在番茄或马铃薯中鉴定和定位、克隆和表达的抗性基因，而番茄或马铃薯对R3bv2的遗传抗性来源非常有限。
Phylogeographic studies inform about routes of pathogen dissemination and are instrumental for improving import/export controls. Genomes of 17 isolates of the bacterial wilt and potato brown rot pathogen Ralstonia solanacearum race 3 biovar 2 (R3bv2), a Select Agent in the United States, were thus analyzed to get insight into the phylogeography of this pathogen. Thirteen of fourteen isolates from Europe, Africa, and Asia were found to belong to a single clonal lineage while isolates from South America were genetically diverse and tended to carry ancestral alleles at the analyzed genomic loci consistent with a South American origin of R3bv2. The R3bv2 isolates share a core repertoire of 31 type III-secreted effector genes representing excellent candidates to be targeted with resistance genes in breeding programs to develop durable disease resistance. Toward this goal, 27 R3bv2 effectors were tested in eggplant, tomato, pepper, tobacco, and lettuce for induction of a hypersensitive-like response indicative of recognition by cognate resistance receptors. Fifteen effectors, eight of them core effectors, triggered a response in one or more plant species. These genotypes may harbor resistance genes that could be identified and mapped, cloned, and expressed in tomato or potato, for which sources of genetic resistance to R3bv2 are extremely limited.