Kato Taro, Morohoshi Tomohiro, Someya Nobutaka, Ikeda Tsukasa
a Department of Material and Environmental Chemistry, Graduate School of Engineering , Utsunomiya University , Utsunomiya , Japan.
Biosci Biotechnol Biochem. 2015;79(4):673-80. doi: 10.1080/09168451.2014.988679. Epub 2014 Dec 8.
Pseudomonas sp. StFLB209 was isolated from potato leaf as an N-acylhomoserine lactone (AHL)-producing bacterium and showed a close phylogenetic relationship with P. cichorii, a known plant pathogen. Although there are no reports of potato disease caused by pseudomonads in Japan, StFLB209 was pathogenic to potato leaf. In this study, we reveal the complete genome sequence of StFLB209, and show that the strain possesses a ppuI-rsaL-ppuR quorum-sensing system, the sequence of which shares a high similarity with that of Pseudomonas putida. Disruption of ppuI results in a loss of AHL production as well as remarkable reduction in motility. StFLB209 possesses strong pectate lyase activity and causes maceration on potato tuber and leaf, which was slightly reduced in the ppuI mutant. These results suggest that the quorum-sensing system is well conserved between StFLB209 and P. putida and that the system is essential for motility, full pectate lyase activity, and virulence in StFLB209.
假单胞菌属菌株StFLB209是从马铃薯叶片中分离得到的一种能产生N-酰基高丝氨酸内酯（AHL）的细菌，与已知的植物病原菌菊苣假单胞菌具有密切的系统发育关系。尽管在日本尚无假单胞菌引起马铃薯病害的报道，但StFLB209对马铃薯叶片具有致病性。在本研究中，我们揭示了StFLB209的完整基因组序列，并表明该菌株具有一个ppuI-rsaL-ppuR群体感应系统，其序列与恶臭假单胞菌的序列具有高度相似性。ppuI的缺失导致AHL产生丧失以及运动性显著降低。StFLB209具有很强的果胶酸裂解酶活性，并导致马铃薯块茎和叶片软腐，在ppuI突变体中这种情况略有减轻。这些结果表明，群体感应系统在StFLB209和恶臭假单胞菌之间高度保守，并且该系统对于StFLB209的运动性、完整的果胶酸裂解酶活性和毒力至关重要。
