Leonard Simon, Villard Camille, Nasser William, Reverchon Sylvie, Hommais Florence
Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS, UMR 5240 MAP, Microbiologie, Adaptation, Pathogénie, Villeurbanne, France.
Front Microbiol. 2021 Jun 24;12:687484. doi: 10.3389/fmicb.2021.687484. eCollection 2021.
is an important pathogenic bacterium that infects a number of crops including potato and chicory. While extensive works have been carried out on the control of the transcription of its genes encoding the main virulence functions, little information is available on the post-transcriptional regulation of these functions. We investigated the involvement of the RNA chaperones Hfq and ProQ in the production of the main virulence functions. Phenotypic assays on the and mutants showed that inactivation of resulted in a growth defect, a modified capacity for biofilm formation and strongly reduced motility, and in the production of degradative extracellular enzymes (proteases, cellulase, and pectate lyases). Accordingly, the mutant failed to cause soft rot on chicory leaves. The mutant had reduced resistance to osmotic stress, reduced extracellular pectate lyase activity compared to the wild-type strain, and reduced virulence on chicory leaves. Most of the phenotypes of the and mutants were related to the low amounts of mRNA of the corresponding virulence factors. Complementation of the double mutant by each individual protein and cross-complementation of each chaperone suggested that they might exert their effects via partially overlapping but different sets of targets. Overall, it clearly appeared that the two Hfq and ProQ RNA chaperones are important regulators of pathogenicity in This underscores that virulence genes are regulated post-transcriptionally by non-coding RNAs.
是一种重要的病原菌，可感染包括马铃薯和菊苣在内的多种作物。虽然在控制其编码主要毒力功能的基因转录方面已经开展了大量工作，但关于这些功能的转录后调控的信息却很少。我们研究了RNA伴侣蛋白Hfq和ProQ在主要毒力功能产生中的作用。对hfq和proQ突变体的表型分析表明，hfq失活导致生长缺陷、生物膜形成能力改变、运动性大幅降低，以及降解性胞外酶（蛋白酶、纤维素酶和果胶酸裂解酶）的产生。因此，hfq突变体无法在菊苣叶片上引起软腐病。proQ突变体对渗透胁迫的抗性降低，与野生型菌株相比，胞外果胶酸裂解酶活性降低，在菊苣叶片上的毒力也降低。hfq和proQ突变体的大多数表型与相应毒力因子的低mRNA水平有关。用每个单独的蛋白对双突变体hfq proQ进行互补以及每个伴侣蛋白的交叉互补表明，它们可能通过部分重叠但不同的靶标集发挥作用。总体而言，很明显Hfq和ProQ这两种RNA伴侣蛋白是该病原菌致病性的重要调节因子。这强调了毒力基因是由非编码RNA进行转录后调控的。
