Lindeberg Magdalen, Myers Christopher R, Collmer Alan, Schneider David J
Department of Plant Pathology, Cornell University, Ithaca, NY 14853, U.S.A.
Mol Plant Microbe Interact. 2008 Jun;21(6):685-700. doi: 10.1094/MPMI-21-6-0685.
Systematic comparison of the current repertoire of virulence-associated genes for three Pseudomonas syringae strains with complete genome sequences, P. syringae pv. tomato DC3,000, P. syringae pv. phaseolicola 1448A, and P. syringae pv. syringae B728a, is prompted by recent advances in virulence factor identification in P. syringae and other bacteria. Among these are genes linked to epiphytic fitness, plant- and insect-active toxins, secretion pathways, and virulence regulators, all reflected in the recently updated DC3,000 genome annotation. Distribution of virulence genes in relation to P. syringae genome organization was analyzed to distinguish patterns of conservation among genomes and association between genes and mobile genetic elements. Variable regions were identified on the basis of deviation in sequence composition and gaps in syntenic alignment among the three genomes. Mapping gene location relative to the genome structure revealed strong segregation of the HrpL regulon with variable genome regions (VR), divergent distribution patterns for toxin genes depending on association with plant or insect pathogenesis, and patterns of distribution for other virulence genes that highlight potential sources of strain-to-strain differences in host interaction. Distribution of VR among other sequenced bacterial genomes was analyzed and future plans for characterization of this potential reservoir of virulence genes are discussed.
丁香假单胞菌的三个具有完整基因组序列的菌株，即丁香假单胞菌番茄致病变种DC3000、丁香假单胞菌菜豆致病变种1448A和丁香假单胞菌丁香致病变种B728a，其目前与毒力相关基因库的系统比较是由丁香假单胞菌及其他细菌在毒力因子鉴定方面的最新进展所推动的。其中包括与附生适应性、植物和昆虫活性毒素、分泌途径以及毒力调节因子相关的基因，所有这些都反映在最近更新的DC3000基因组注释中。分析了毒力基因相对于丁香假单胞菌基因组组织的分布，以区分基因组间的保守模式以及基因与可移动遗传元件之间的关联。基于三个基因组序列组成的偏差和共线性比对中的缺口确定了可变区。相对于基因组结构绘制基因位置图，揭示了HrpL调控子与可变基因组区域（VR）的强烈分离、毒素基因根据与植物或昆虫致病作用的关联而呈现的不同分布模式，以及其他毒力基因的分布模式，这些模式突出了宿主相互作用中菌株间差异的潜在来源。分析了VR在其他已测序细菌基因组中的分布，并讨论了表征这个潜在毒力基因库的未来计划。
