Abstract—

The regulatory protein encoded by the rosR gene is involved in the processes of adaptation of root nodule bacteria Rhizobium leguminosarum to changes in environmental conditions. It affects the expression of a number of genes associated with the synthesis of exopolysaccharides, which play a critical role in formation of bacterial biofilms on various surfaces. The goal of this work was to study the effect of overexpression of the rosR gene on formation of R. leguminosarum biofilms on inert surfaces and roots of heterologous plant hosts by obtaining recombinant strains with an additional copy of the rosR gene under the control of the Pm promoter. Our analysis of recombinant strains showed that additional expressed copies of the rosR gene allowed rhizobia to overcome the inhibitory effect on biofilm formation caused by low calcium concentrations in the medium, the effect of proteases and detergents, and to form biofilms more efficiently on the surface of tomato and clover roots. The results obtained open up prospects for using rosR as a tool both for increasing the efficiency of endosymbiosis of rhizobia with legumes, and for the formation of stable associative interactions with other agricultural crops.

中文翻译：

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rosR基因过表达对豆科根瘤菌生物膜形成的影响

摘要—

rosR基因编码的调节蛋白参与根瘤菌根瘤菌对环境条件的适应过程。它影响与胞外多糖合成相关的许多基因的表达，胞外多糖在各种表面细菌生物膜的形成中起关键作用。这项工作的目的是通过获得带有额外拷贝的rosR的重组菌株，研究rosR基因的过表达对异源植物宿主惰性表面和根上豆科植物豆类生物膜形成的影响。Pm启动子控制的基因。我们对重组菌株的分析表明，额外表达的rosR基因拷贝使根瘤菌克服了培养基中钙浓度低引起的对生物膜形成的抑制作用，蛋白酶和去污剂的作用，并更有效地在细菌表面形成了生物膜。番茄和三叶草的根。结果为使用rosR作为工具来提高豆科植物的根瘤菌内共生效率以及与其他农作物形成稳定的缔合相互作用开辟了前景。