Wang Bowen, Huang Bingfen, Chen Junmei, Li Wenpeng, Yang Ling, Yao Lunguang, Niu Qiuhong
Department of Life Science and Biotechnology, Nanyang Normal University, Nanyang, 473000, People's Republic of China.
Nanyang Academy of Agricultural Sciences, Nanyang, 473083, Henan, People's Republic of China.
Mol Biol Rep. 2019 Apr;46(2):1563-1575. doi: 10.1007/s11033-018-04574-w. Epub 2019 Mar 16.
Colonization resistance is an important attribute for bacterial interactions with hosts, but the mechanism is still not completely clear. In this study, we found that Phytobacter sp. SCO41 can effectively inhibit the in vivo colonization of Bacillus nematocida B16 in Caenorhabditis elegans, and we revealed the colonization resistance mechanism. Three strains of colonization-resistant bacteria, SCO41, BX15, and BC7, were isolated from the intestines of the free-living nematode C. elegans derived from rotten fruit and soil. The primary characteristics and genome map of one of the three isolates was investigated to explore the underlying mechanism of colonization resistance in C. elegans. In addition, we performed exogenous iron supplementation and gene cluster knockout experiments to validate the sequencing results. The results showed that relationship was close among the three strains, which was identified as belonging to the genus Phytobacter. The type strain is SCO41 (= CICC 24103 = KCTC 52362). Whole genome analysis showed that csgA, csgB, csgC, csgE, csgF, and csgG were involved in the curli adhesive process and that fepA, fepB, fepC, fepD, and fepG played important roles in SCO41 against the colonization of B. nematocida B16 in C. elegans by competing for iron. Exogenous iron supplementation showed that exogenous iron can increase the colonization of B. nematocida B16, which was additionally confirmed by a deletion mutant strain. The csg gene family contributes to the colonization of SCO41 in C. elegans. Curli potentially contribute to the colonization of SCO41 in C. elegans, and enterobactin has a key role in SCO41 to resist the colonization of B. nematocida B16 by competing for iron.
定殖抗性是细菌与宿主相互作用的一个重要特性，但其机制仍不完全清楚。在本研究中，我们发现植物杆菌属菌株SCO41能够有效抑制杀线虫芽孢杆菌B16在秀丽隐杆线虫体内的定殖，并揭示了定殖抗性机制。从腐烂水果和土壤中分离得到的自由生活线虫秀丽隐杆线虫的肠道中，分离出三株具有定殖抗性的细菌SCO41、BX15和BC7。对这三株分离菌之一的主要特征和基因组图谱进行了研究，以探索秀丽隐杆线虫定殖抗性的潜在机制。此外，我们进行了外源铁补充和基因簇敲除实验，以验证测序结果。结果表明，这三株菌亲缘关系密切，均被鉴定为植物杆菌属。模式菌株为SCO41（=CICC 24103=KCTC 52362）。全基因组分析表明，csgA、csgB、csgC、csgE、csgF和csgG参与了卷曲菌毛黏附过程，而fepA、fepB、fepC、fepD和fepG通过竞争铁在SCO41抵抗杀线虫芽孢杆菌B16在秀丽隐杆线虫体内定殖中发挥重要作用。外源铁补充实验表明，外源铁可增加杀线虫芽孢杆菌B16的定殖，缺失突变株进一步证实了这一点。csg基因家族有助于SCO41在秀丽隐杆线虫体内定殖。卷曲菌毛可能有助于SCO41在秀丽隐杆线虫体内定殖，而肠杆菌素在SCO41通过竞争铁抵抗杀线虫芽孢杆菌B16定殖中起关键作用。
