Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA.
Microb Biotechnol. 2008 Jan;1(1):17-29. doi: 10.1111/j.1751-7915.2007.00002.x.
Whole-transcriptome analysis was used here for the first time in the rhizosphere to discern the genes involved in the pathogenic response of Pseudomonas aeruginosa PAO1 as well as to discern the response of the poplar tree. Differential gene expression shows that 185 genes of the bacterium and 753 genes of the poplar tree were induced in the rhizosphere. Using the P. aeruginosa transcriptome analysis, isogenic knockout mutants, and two novel plant assays (poplar and barley), seven novel PAO1 virulence genes were identified (PA1385, PA2146, PA2462, PA2463, PA2663, PA4150 and PA4295). The uncharacterized putative haemolysin repressor, PA2463, upon inactivation, resulted in greater poplar virulence and elevated haemolysis while this mutant remained competitive in the rhizosphere. In addition, disruption of the haemolysin gene itself (PA2462) reduced the haemolytic activity of P. aeruginosa, caused less cytotoxicity and reduced barley virulence, as expected. Inactivating PA1385, a putative glycosyl transferase, reduced both poplar and barley virulence. Furthermore, disrupting PA2663, a putative membrane protein, reduced biofilm formation by 20-fold. Inactivation of PA3476 (rhlI) increased virulence with barley as well as haemolytic activity and cytotoxicity, so quorum sensing is important in plant pathogenesis. Hence, this strategy is capable of elucidating virulence genes for an important pathogen.
首次在根际中使用全转录组分析来辨别铜绿假单胞菌 PAO1 的致病反应相关基因，并辨别杨树的反应。差异基因表达表明，细菌中有 185 个基因和杨树中有 753 个基因在根际中被诱导。利用铜绿假单胞菌转录组分析、同源敲除突变体和两种新的植物测定（杨树和大麦），鉴定了 7 个新的 PAO1 毒力基因（PA1385、PA2146、PA2462、PA2463、PA2663、PA4150 和 PA4295）。未表征的假定溶血素抑制剂 PA2463 失活后，导致杨树毒力增加和溶血增加，而该突变体在根际中仍具有竞争力。此外，溶血素基因本身（PA2462）的破坏降低了铜绿假单胞菌的溶血活性，导致细胞毒性降低和大麦毒力降低，这是预期的。失活 PA1385，一种假定的糖基转移酶，降低了杨树和大麦的毒力。此外，破坏 PA2663，一种假定的膜蛋白，使生物膜形成减少 20 倍。PA3476（rhlI）的失活增加了与大麦以及溶血活性和细胞毒性相关的毒力，因此群体感应在植物发病机制中很重要。因此，这种策略能够阐明重要病原体的毒力基因。
