Fan Xiaojing, Yang Ruixian, Qiu Sixin, Cai Xueqing, Zou Huasong, Hu Fangping
College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, P.R. China.
Department of Environmental Engineering and Chemistry, Luoyang Institute of Science and Technology, Luoyang, Henan 471023, P.R. China.
J Microbiol Biotechnol. 2016 May 28;26(5):946-52. doi: 10.4014/jmb.1512.12055.
The eglS gene in Bacillus amyloliquefaciens encodes an endo-β-1,4-glucanase that belongs to glycosyl hydrolase family 5. In this study, a disruption mutant of gene eglS was constructed to examine its role in bacterial adaptation in plants. The mutant TB2k, eglS gene inactivated bacterial strain, was remarkably impaired in extracellular cellulase activity. When inoculated on Brassica campestris, the TB2k population was reduced by more than 60% compared with the wild-type strain in the root, stem, and leaf tissues. Overexpression of eglS in the wild-type strain increased the bacteria population in the plant tissues. Further studies revealed that the transcription level of eglS was correlated with bacterial population. These data demonstrate that endo-β-1,4-glucanase of B. amyloliquefaciens is required for its optimal endophytic colonization.
解淀粉芽孢杆菌中的eglS基因编码一种属于糖基水解酶家族5的内切β-1,4-葡聚糖酶。在本研究中，构建了eglS基因的破坏突变体以研究其在细菌适应植物过程中的作用。突变体TB2k，即eglS基因失活的菌株，其胞外纤维素酶活性显著受损。当接种到油菜上时，与野生型菌株相比，TB2k在根、茎和叶组织中的数量减少了60%以上。野生型菌株中eglS的过表达增加了植物组织中的细菌数量。进一步研究表明，eglS的转录水平与细菌数量相关。这些数据表明解淀粉芽孢杆菌的内切β-1,4-葡聚糖酶是其最佳内生定殖所必需的。
