1 School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, U.S.A.; and.
2 Emerging Pests & Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, NY 14853, U.S.A.
Mol Plant Microbe Interact. 2017 Apr;30(4):283-294. doi: 10.1094/MPMI-09-16-0196-R. Epub 2017 Apr 6.
Pseudomonas syringae infects diverse plant species and is widely used as a model system in the study of effector function and the molecular basis of plant diseases. Although the relationship between bacterial metabolism, nutrient acquisition, and virulence has attracted increasing attention in bacterial pathology, it is largely unexplored in P. syringae. The Crc (catabolite repression control) protein is a putative RNA-binding protein that regulates carbon metabolism as well as a number of other factors in the pseudomonads. Here, we show that deletion of crc increased bacterial swarming motility and biofilm formation. The crc mutant showed reduced growth and symptoms in Arabidopsis and tomato when compared with the wild-type strain. We have evidence that the crc mutant shows delayed hypersensitive response (HR) when infiltrated into Nicotiana benthamiana and tobacco. Interestingly, the crc mutant was more susceptible to hydrogen peroxide, suggesting that, in planta, the mutant may be sensitive to reactive oxygen species generated during pathogen-associated molecular pattern-triggered immunity (PTI). Indeed, HR was further delayed when PTI-induced tissues were challenged with the crc mutant. The crc mutant did not elicit an altered PTI response in plants compared with the wild-type strain. We conclude that Crc plays an important role in growth and survival during infection.
丁香假单胞菌感染多种植物物种,是研究效应子功能和植物疾病分子基础的广泛应用模式系统。尽管细菌代谢、营养获取和毒力之间的关系在细菌病理学中越来越受到关注,但在丁香假单胞菌中很大程度上仍未得到探索。Crc(分解代谢物阻遏控制)蛋白是一种假定的 RNA 结合蛋白,可调节碳代谢以及假单胞菌中的许多其他因素。在这里,我们表明 crc 的缺失增加了细菌的群集运动和生物膜形成。与野生型菌株相比,crc 突变体在拟南芥和番茄中显示出生长和症状的减少。我们有证据表明,crc 突变体在侵染 Nicotiana benthamiana 和烟草时表现出延迟的过敏反应 (HR)。有趣的是,crc 突变体对过氧化氢更敏感,这表明在植物中,突变体可能对病原体相关分子模式触发免疫 (PTI) 过程中产生的活性氧敏感。事实上,当用 crc 突变体挑战 PTI 诱导的组织时,HR 进一步延迟。与野生型菌株相比,crc 突变体在植物中没有引起改变的 PTI 反应。我们得出结论,Crc 在感染过程中的生长和存活中发挥重要作用。