Type III Secretion-Dependent and -Independent Phenotypes Caused by Ralstonia solanacearum in Arabidopsis Roots
Type III Secretion-Dependent and -Independent Phenotypes Caused by Ralstonia solanacearum in Arabidopsis Roots
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DOI：
10.1094/mpmi-05-17-0109-fi
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发表时间：
2018-01-01
影响因子：
3.5
通讯作者：
Coll, Nuria S.
中科院分区：
文献类型：
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作者：
Lu, Haibin;Lema, Saul A.;Coll, Nuria S.
青枯病的病原菌青枯病是一种土传病原体，通过植物的根入侵植物，穿过许多组织层直到到达木质部，在那里繁殖并导致植物倒塌。青枯菌感染的影响是毁灭性的，到目前为止还没有有效的方法来抗击这种疾病。侵染的早期步骤，以及早期的植物防御反应，对于定殖是必不可少的，目前大多尚不清楚。在这里，我们建立了一个简单的体外拟南芥-R。青枯菌的致病机制，使我们能够确定与感染早期阶段相关的三种明确的根表型：根生长抑制、根毛形成和根尖细胞死亡。利用这种方法，我们已经能够在拟南芥植物上区分关键细菌毒力调节因子hrpB和hrpG的突变体引起的表型，这两种表型在经典的土壤淋洗接种致病试验中仍然是无法区分的。此外，我们还揭示了以前未知的生长素参与青枯病菌侵染引起的根的重排。我们的系统提供了一个简单易用、高通量的工具来研究青枯病菌的侵袭性。此外，观察到的表型可以用来鉴定细菌的毒性决定因素，甚至可以用来筛选早期植物对青枯病的新形式的抗性。
The causal agent of bacterial wilt, Ralstonia solanacearum, is a soilborne pathogen that invades plants through their roots, traversing many tissue layers until it reaches the xylem, where it multiplies and causes plant collapse. The effects of R. solanacearum infection are devastating, and no effective approach to fight the disease is so far available. The early steps of infection, essential for colonization, as well as the early plant defense responses remain mostly unknown. Here, we have set up a simple, in vitro Arabidopsis thaliana-R. solanacearum pathosystem that has allowed us to identify three clear root phenotypes specifically associated to the early stages of infection: root-growth inhibition, root-hair formation, and root-tip cell death. Using this method, we have been able to differentiate, on Arabidopsis plants, the phenotypes caused by mutants in the key bacterial virulence regulators hrpB and hrpG, which remained indistinguishable using the classical soil-drench inoculation pathogenicity assays. In addition, we have revealed the previously unknown involvement of auxins in the root re-arrangements caused by R. solanacearum infection. Our system provides an easy-to-use, high-throughput tool to study R. solanacearum aggressiveness. Furthermore, the observed phenotypes may allow the identification of bacterial virulence determinants and could even be used to screen for novel forms of early plant resistance to bacterial wilt.