Background and aims

Plant-associated microbiotas play a key role in plant health, growth, and stresses resilience. One main component of the plant microbiota is the endophytic bacterial communities, which live inside the internal tissues. The principal sources of this microbiota are the seed and the soil. Particularly, soil bacteria are attracted by different signals present in plant root exudates, to colonize the rhizoplane later to infect internal tissues. Although endophytic bacteria’s colonization and infection processes are well documented, the molecular bases of the mechanisms involved are still poorly understood. Previously it was shown that endophytic strain Kosakonia radicincitans UYSO10 promotes the growth of sugarcane plants and was defined as a true endophyte. It was also demonstrated that the biological nitrogen fixation process is involved in plant growth promotion by the strain UYSO10. This work aimed to expand the knowledge about the adaptations of the diazotrophic endophytic strain UYSO10 to sugarcane root exudates, and identify possible mechanisms involved.

Methodology

Two quantitative complementary proteomic techniques were used to study the response of the strain UYSO10 to sugarcane root exudates.

Results

Roots exudates induce quantifiable changes in the strain UYSO10 bacterial proteome, including the remodeling of several pathways toward the metabolic adaptation to the nutrients available, the bacterial membrane remodeling, and changes that allow the shift from a planktonic lifestyle to biofilm formation.

Conclusions

Results deepen the knowledge of the bacterial adaptation to the rhizosphere environment toward root infection, and identify potential mechanisms involved in the sugarcane plant-UYSO10 strain interaction.

中文翻译：

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甘蔗根系分泌物对内生菌株 Kosakonia radicincitans UYSO10 蛋白质组的调控

 背景和目标

植物相关微生物群在植物健康、生长和压力恢复力中起着关键作用。植物微生物群的一个主要组成部分是生活在内部组织的内生细菌群落。这种微生物群的主要来源是种子和土壤。特别是，土壤细菌被植物根系分泌物中存在的不同信号所吸引，随后在根际定植以感染内部组织。尽管内生细菌的定植和感染过程有据可查，但对其机制的分子基础仍然知之甚少。以前表明，内生菌株 Kosakonia radicincitans UYSO10 促进甘蔗植物的生长，并被定义为真正的内生菌。研究还表明，生物固氮过程参与菌株 UYSO10 的植物生长促进。这项工作旨在扩大关于固氮营养内生菌株 UYSO10 对甘蔗根系分泌物适应性的认识，并确定可能的机制。

 方法论

采用两种定量互补蛋白质组学技术研究菌株 UYSO10 对甘蔗根系分泌物的响应。

 结果

根系分泌物诱导菌株 UYSO10 细菌蛋白质组的可量化变化，包括对可用营养物质的代谢适应的几种途径的重塑、细菌膜重塑以及允许从浮游生活方式转变为生物膜形成的变化。

 结论

结果加深了细菌对根际环境对根系感染的适应的认识，并确定了甘蔗植物-UYSO10 菌株相互作用的潜在机制。