Gong Ya, Zhang Zheng, Zhou Xiu-Wen, Anwar Mian N, Hu Xiao-Zhuang, Li Ze-Shuo, Chen Xiao-Jing, Li Yue-Zhong
State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, China.
Front Microbiol. 2018 Jun 5;9:1200. doi: 10.3389/fmicb.2018.01200. eCollection 2018.
Due to the high similarity in their requirements for space and food, close bacterial relatives may be each other's strongest competitors. Close bacterial relatives often form visible boundaries to separate their swarming colonies, a phenomenon termed colony-merger incompatibility. While bacterial species are known to have many incompatible strains, it is largely unclear which traits lead to multiple incompatibilities and the interactions between multiple incompatible siblings. To investigate the competitive interactions of closely related incompatible strains, we mutated DK1622, a predatory bacterium with complex social behavior. From 3392 random transposon mutations, we obtained 11 self-identification (SI) deficient mutants that formed unmerged colony boundaries with the ancestral strain. The mutations were at nine loci with unknown functions and formed nine independent SI mutants. Compared with their ancestral strain, most of the SI mutants showed reduced growth, swarming and development abilities, but some remained unchanged from their monocultures. When pairwise mixed with their ancestral strain for co-cultivation, these mutants exhibited improved, reduced or unchanged competitive abilities compared with the ancestral strain. The sporulation efficiencies were affected by the DK1622 partner, ranging from almost complete inhibition to 360% stimulation. The differences in competitive growth between the SI mutants and DK1622 were highly correlated with the differences in their sporulation efficiencies. However, the competitive efficiencies of the mutants in mixture were inconsistent with their growth or sporulation abilities in monocultures. We propose that the colony-merger incompatibility in is associated with multiple independent genetic loci, and the incompatible strains hold competitive interaction abilities, which probably determine the complex relationships between multiple incompatible strains and their co-existence strategies.
由于它们对空间和食物的需求高度相似，亲缘关系相近的细菌可能是彼此最强的竞争者。亲缘关系相近的细菌常常形成可见的边界来分隔它们的群体，这种现象被称为群体融合不相容性。虽然已知细菌物种有许多不相容的菌株，但很大程度上不清楚哪些特征导致多种不相容性以及多个不相容菌株之间的相互作用。为了研究亲缘关系相近的不相容菌株之间的竞争相互作用，我们对具有复杂社会行为的捕食性细菌DK1622进行了突变。从3392个随机转座子突变中，我们获得了11个自我识别（SI）缺陷型突变体，它们与原始菌株形成了未融合的群体边界。这些突变位于9个功能未知的位点，形成了9个独立的SI突变体。与原始菌株相比，大多数SI突变体的生长、群体运动和发育能力降低，但有些在单培养中保持不变。当与原始菌株成对混合进行共培养时，这些突变体与原始菌株相比表现出提高、降低或不变的竞争能力。孢子形成效率受到DK1622伙伴的影响，范围从几乎完全抑制到360%的刺激。SI突变体与DK1622之间竞争生长的差异与其孢子形成效率的差异高度相关。然而，突变体在混合培养中的竞争效率与其在单培养中的生长或孢子形成能力不一致。我们提出，[文中未提及具体物种，此处翻译为“该物种”]中的群体融合不相容性与多个独立的基因位点相关，并且不相容菌株具有竞争相互作用能力，这可能决定了多个不相容菌株之间的复杂关系及其共存策略。
