Zhao Xia, Wang Ruoyu, Shang Qianhan, Hao Haiting, Li Yuyao, Zhang Yubao, Guo Zhihong, Wang Yun, Xie Zhongkui
Gaolan Station of Agricultural and Ecological Experiment, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China; University of Chinese Academy of Sciences, Beijing, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province, Lanzhou, China.
Gaolan Station of Agricultural and Ecological Experiment, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions of Gansu Province, Lanzhou, China.
Microbiol Res. 2016 Mar;184:25-31. doi: 10.1016/j.micres.2015.12.004. Epub 2015 Dec 23.
Collagen-like proteins (CLPs) share the distinctive Gly-X-Thr repeating amino acid sequence of animal collagens, and contain N- and C-terminal domain making a collagen-like structure in Bacillus amyloliquefaciens FZB42, a plant growth-promoting rhizobacterium. Our previous study demonstrated that CLPs play important roles in biofilm construction and adherence to the surfaces on plant roots. However, bacterial localization of the CLPs remains unclear. Here, disrupted strains on all four clp genes (clpA, clpB, clpC and clpD) shown fewer filament than wild-type bacteria in extracellular matrix under scanning electron microscope (SEM). Transmission electron microscopy (TEM) was used to observe the differences on filament which associated on the cell surface, then the CLPs mutation strains showed less flagella than the wild type. Immunogold labeling determined the location that ClpB and ClpC localized on the flagella surface. In addition, western blotting analysis of crude flagella extracts suggested that the ClpB and ClpC are associated to flagella as well. The mutation strains also reduced motility of swimming on the surface of soft agar medium and changed the architectural of microcolony biofilm edge. The study suggests that collagen-like protein ClpB and ClpC, as novel proteins, associated with flagella in B. amyloliquefaciens.
类胶原蛋白（CLPs）具有动物胶原蛋白独特的甘氨酸- X -苏氨酸重复氨基酸序列，并含有N端和C端结构域，在植物促生根际细菌解淀粉芽孢杆菌FZB42中形成类胶原蛋白结构。我们之前的研究表明，CLPs在生物膜构建以及在植物根表面的附着过程中发挥重要作用。然而，CLPs在细菌中的定位仍不清楚。在此，扫描电子显微镜（SEM）下观察到，所有四个clp基因（clpA、clpB、clpC和clpD）的缺失菌株在细胞外基质中的丝状结构比野生型细菌少。利用透射电子显微镜（TEM）观察细胞表面相关丝状结构的差异，结果显示CLPs突变菌株的鞭毛比野生型少。免疫金标记确定了ClpB和ClpC定位于鞭毛表面。此外，对粗鞭毛提取物的蛋白质免疫印迹分析表明，ClpB和ClpC也与鞭毛相关。突变菌株在软琼脂培养基表面的游动能力也降低，并且改变了微菌落生物膜边缘的结构。该研究表明，类胶原蛋白ClpB和ClpC作为新的蛋白质，在解淀粉芽孢杆菌中与鞭毛相关。
