In planta induced changes in the native plasmid profile of Pseudomonas syringae pathover phaseolicola strain 1302A
In planta induced changes in the native plasmid profile of Pseudomonas syringae pathover phaseolicola strain 1302A
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DOI：
10.1016/j.plasmid.2013.07.002
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发表时间：
2013-11-01
期刊：
影响因子：
2.6
通讯作者：
Arnold, Dawn L.
中科院分区：
文献类型：
--
作者：
Neale, Helen C.;Slater, Ross T.;Arnold, Dawn L.
丁香假单胞菌 pv.菜豆 (Pph) 菌株 1302A 是菜豆菜豆 (Phaseolus vulgaris) 中晕枯病的病原体，含有四种天然质粒，分别命名为 pAV505 (150 kb)、pAV506 (50 kb)、pAV507 (47 kb) 和 pAV508 (42 kb)。 Pph 1302A 还包含一个 106 kb 基因组岛 PPHGI-1，其与整合和接合元件 (ICElands) 具有相同的特征，并携带效应基因 avrPphB (hopAR1)，该基因在携带匹配 R3 抗性基因的豆品种中触发防御反应。结果表明，当Pph 1302A依次接种（传代）产生过敏反应（HR）的抗性豆品种Tendergreen（TG）时，三个最大的质粒丢失，并获得额外的类似于100kb的质粒，经测试证实该质粒是PPHGI-1的106kb环状形式。当前研究的目的是确定在进一步传代豆类植物后，Pph 1302A 的质粒谱是否会再次改变，以及缺失的质粒是否已整合到染色体中。 Pph 1302A-P6，具有改变的质粒谱的菌株通过TG传代两次，并且在检查的四个重新分离的菌株中，全部显示与野生型Pph 1302A相关的质粒谱，即，所有四个天然质粒都重新出现并且PPHGI-1质粒不存在。这表明 Pph 1302A-P6 的质粒组成确实可以在进一步暴露于植物环境时发生变化，而且看似缺失的天然质粒仍然存在于基因组中，这为它们已整合到染色体中的理论提供了证据。此外，其中两个重新分离的菌株完全失去了 PPHGI-1，这意味着它们不再触发 TG 上的 HR，而是产生疾病反应。这项研究清楚地证明了细菌基因组的可塑性以及它受植物环境和同源反应过程中产生的条件影响的程度。 (C) 2013 Elsevier Inc. 保留所有权利。
Pseudomonas syringae pv. phaseolicola (Pph) strain 1302A, a causative agent of halo blight in the common bean Phaseolus vulgaris, contains four native plasmids designated pAV505 (150 kb), pAV506 (50 kb), pAV507 (47 kb) and pAV508 (42 kb). Pph 1302A also contains a 106 kb genomic island PPHGI-1 which shares features with integrative and conjugative elements (ICElands) and carries the effector gene avrPphB (hopAR1) which triggers a defensive response in bean cultivars carrying the matching R3 resistance gene. It has been shown that when Pph 1302A is sequentially inoculated (passaged) through resistant bean cultivar Tendergreen (TG) in which the hypersensitive response (HR) is generated, the three largest plasmids are lost and an extra similar to 100 kb plasmid is gained, which tests confirmed to be the 106 kb circular form of PPHGI-1. The aim of the current study was to determine if upon further passaging though bean plants, the plasmid profile of Pph 1302A would alter again and if the missing plasmids had been integrated into the chromosome. Pph 1302A-P6, the strain with the altered plasmid profile was passaged twice through TG and of the four re-isolated strains examined all displayed the plasmid profile associated with wildtype Pph 1302A, that is, all four native plasmids had reappeared and the PPHGI-1 plasmid was absent. This demonstrated that the plasmid composition of Pph 1302A-P6 could indeed change on further exposure to the plant environment and also that the seemingly missing native plasmids were still present within the genome, lending evidence to the theory that they had integrated into the chromosome. Furthermore two of these re-isolated strains had lost PPHGI-1 entirely, meaning they no longer triggered a HR on TG and instead generated a disease response. This study clearly demonstrates the plasticity of the bacterial genome and the extent it can be influenced by the plant environment and conditions generated during the HR. (C) 2013 Elsevier Inc. All rights reserved.