Primo Emiliano, Bogino Pablo, Cossovich Sacha, Foresto Emiliano, Nievas Fiorela, Giordano Walter
Instituto de Biotecnología Ambiental y Salud (INBIAS), CONICET, Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Río Cuarto X5804BYA, Córdoba, Argentina.
Molecules. 2020 Oct 22;25(21):4876. doi: 10.3390/molecules25214876.
is a soil bacterium of great agricultural importance because of its ability to fix atmospheric nitrogen in symbiotic association with alfalfa () roots. We looked into the involvement of exopolysaccharides (EPS) in its survival when exposed to different environmental stressors, as well as in bacteria-bacteria and bacteria-substrate interactions. The strains used were wild-type Rm8530 and two strains that are defective in the biosynthesis of EPS II: wild-type Rm1021, which has a non-functional locus, and mutant Rm8530 . Under stress by water deficiency, Rm8530 remained viable and increased in number, whereas Rm1021 and Rm8530 did not. These differences could be due to Rm8530's ability to produce EPS II. Survival experiments under saline stress showed that viability was reduced for Rm1021 but not for Rm8530 or Rm8530 , which suggests the existence of some regulating mechanism dependent on a functional that is absent in Rm1021. The results of salinity-induced stress assays regarding biofilm-forming capacity (BFC) and autoaggregation indicated the protective role of EPS II. As a whole, our observations demonstrate that EPS play major roles in rhizobacterial survival.
是一种对农业具有重要意义的土壤细菌，因为它能够与苜蓿根形成共生关系，固定大气中的氮。我们研究了胞外多糖（EPS）在其暴露于不同环境应激源时的存活情况，以及在细菌-细菌和细菌-底物相互作用中的作用。所用菌株为野生型Rm8530和两种EPS II生物合成有缺陷的菌株：野生型Rm1021，其 位点无功能，以及突变体Rm8530 。在缺水胁迫下，Rm8530仍能存活且数量增加，而Rm1021和Rm8530 则不能。这些差异可能是由于Rm8530产生EPS II的能力。盐胁迫下的存活实验表明，Rm1021的活力降低，但Rm8530或Rm8530 则没有，这表明存在某种依赖于Rm1021中不存在的功能性 的调节机制。关于生物膜形成能力（BFC）和自聚集的盐度诱导胁迫试验结果表明了EPS II的保护作用。总体而言，我们的观察结果表明EPS在根际细菌存活中起主要作用。
