Zhang Liaoyuan, Guo Zewang, Gao Huifang, Peng Xiaoqian, Li Yongyu, Sun Shujing, Lee Jung-Kul, Lin Wenxiong
Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea.
Key Laboratory of Biopesticide and Chemical Biology, Ministry of Education, College of Life Sciences, Gutian Edible Fungi Research Institute, Fujian Agriculture and Forestry University, Fuzhou, Fujian Province, 350002, P.R. China.
J Microbiol Biotechnol. 2016 Dec 28;26(12):2159-2170. doi: 10.4014/jmb.1607.07073.
Many plant-pathogenic bacteria are dependent on quorum sensing (QS) to evoke disease. In this study, the population of QS and quorum quenching (QQ) bacteria was analyzed in a consecutive monoculture system of . The isolated QS strains were identified as with -type QS system and exhibited a significant increase over the years of monoculture. Only one QQ strain was isolated from newly planted soil sample and was identified as , which secreted lactonase to degrade QS signal molecules. Inoculation of to root could rapidly cause wilt disease, which was alleviated by . Furthermore, the expression of lactonase encoded by the gene in resulted in reduction of its pathogenicity, implying that the toxic effect of on the seedlings was QS-regulated. Meanwhile, excess lactonase in led to reduction in antibacterial substances, exoenzymes, and swarming motility, which might contribute to pathogensis on the seedlings. Root exudates and root tuber extracts of significantly promoted the growth of , whereas a slight increase of was observed in both samples. These results demonstrated that QS-regulated behaviors in mediated by root exudates played an important role in replanting diseases of .
许多植物病原细菌依靠群体感应（QS）引发病害。在本研究中，对连续单作系统中的群体感应和群体淬灭（QQ）细菌群体进行了分析。分离出的群体感应菌株被鉴定为具有 - 型群体感应系统，并且在多年的单作过程中显著增加。仅从新种植的土壤样本中分离出一株群体淬灭菌株，鉴定为 ，其分泌内酯酶以降解群体感应信号分子。将 接种到 根部可迅速引发枯萎病，而 可缓解该病。此外， 基因编码的内酯酶在 中的表达导致其致病性降低，这意味着 对幼苗的毒性作用是由群体感应调节的。同时， 中过量的内酯酶导致抗菌物质、胞外酶和群体运动性减少，这可能有助于其对幼苗的致病作用。 的根系分泌物和块根提取物显著促进了 的生长，而在这两个样本中均观察到 略有增加。这些结果表明，根系分泌物介导的 中群体感应调节的行为在 的连作病害中起重要作用。
