Department of Plant Science, Faculty of Agricultural and Environmental Sciences, McGill University, 21 111 Lakeshore Drive, Sainte-Anne-de-Bellevue, Quebec H9X 3V9, Canada.
Can J Microbiol. 2020 Oct;66(10):562-575. doi: 10.1139/cjm-2020-0041. Epub 2020 Apr 29.
Root colonization by plant-growth-promoting bacteria could not be useful without the beneficial properties of the bacterium itself. Thus, it is necessary to evaluate the bacterial capacity to form biofilms and establish a successful interaction with the plant roots. We assessed the ability of growth-promoting bacterial strains to form biofilm and display chemotactic behaviour in response to organic acids and (or) root exudates of the model plant This assessment was based on the evaluation of single strains of bacteria and a multispecies consortium. The strains coexisted together and formed biofilm under biotic (living root) and abiotic (glass) surfaces. Citric acid stimulated biofilm formation in all individual strains, indicating a strong chemotactic behaviour towards organic acids. Recognizing that the transition from single strains of bacteria to a "multicellular" system would not happen without the presence of adhesion, the alginate and exopolysaccharide (EPS) contents were evaluated. The EPS amounts were comparable in single strains and consortium forms. Alginate production increased 160% in the consortium subjected to drought stress (10% PEG). These findings demonstrated that () bacteria-bacteria interaction is the hub of various factors that would not only affect their relation but also could indirectly affect the balanced plant-microbe relation and () root exudates could be very selective in recruiting a highly qualified multispecies consortium.
如果没有细菌本身的有益特性，植物促生菌的根定植就不会有用。因此，有必要评估细菌形成生物膜的能力，并与植物根系建立成功的相互作用。我们评估了促生细菌菌株形成生物膜的能力，并对其在响应有机酸和/或模式植物根分泌物时表现出的趋化行为进行了评估。这种评估是基于对单个细菌菌株和多菌种联合体的评估。在生物（活根）和非生物（玻璃）表面，菌株共同存在并形成生物膜。柠檬酸刺激所有单个菌株形成生物膜，表明其对有机酸具有强烈的趋化行为。鉴于从单个菌株向“多细胞”系统的转变如果没有黏附的存在就不会发生，因此评估了藻酸盐和胞外多糖 (EPS) 的含量。单个菌株和联合体形式的 EPS 含量相当。在受到干旱胁迫（10%PEG）的联合体中，藻酸盐的产量增加了 160%。这些发现表明，（）细菌-细菌相互作用是各种因素的中心，这些因素不仅会影响它们之间的关系，还会间接影响植物-微生物之间的平衡关系，（）根分泌物在招募具有高度资格的多菌种联合体方面可能非常有选择性。
