Induced root-secreted D-galactose functions as a chemoattractant and enhances the biofilm formation of Bacillus velezensis SQR9 in an McpA-dependent manner
Induced root-secreted D-galactose functions as a chemoattractant and enhances the biofilm formation of Bacillus velezensis SQR9 in an McpA-dependent manner
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诱导根分泌的 D-半乳糖作为化学引诱剂，并以 McpA 依赖性方式增强贝莱森芽孢杆菌 SQR9 生物膜的形成
DOI：
10.1007/s00253-019-10265-8
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发表时间：
2020-01-01
影响因子：
5
通讯作者：
Zhang, Ruifu
中科院分区：
文献类型：
--
作者：
Liu, Yunpeng;Feng, Haichao;Zhang, Ruifu
对根系分泌物的趋化性和随后的生物膜形成对于根部定殖和提供植物促进根际细菌（PGPR）的有益功能非常重要。在这项研究中，与其他根部分泌的化合物相比，黄瓜根部分泌物中的D-半乳糖被发现在浓度为1μM时对贝莱森芽孢杆菌SQR9具有很强的化学引诱剂。使用甲基接受趋化蛋白 (MCP) 缺失菌株进行的趋化测定表明，McpA 唯一负责对 D-半乳糖的趋化作用。有趣的是，D-半乳糖以 McpA 依赖性方式显着增强 SQR9 的生物膜形成。进一步的实验表明，D-半乳糖还增强了SQR9在根部的定殖。此外，接种SQR9可以诱导黄瓜根部分泌D-半乳糖，表明D-半乳糖可能是植物与SQR9相互作用的重要信号。这些发现表明根部分泌的D-半乳糖是一种信号，其分泌是由有益细菌诱导的，进而诱导细菌定植。
Chemotaxis towards root exudates and subsequent biofilm formation are very important for root colonization and for providing the beneficial functions of plant growth-promoting rhizobacteria (PGPRs). In this study, in comparison with other root-secreted compounds, D-galactose in the root exudates of cucumber was found to be a strong chemoattractant at the concentration of 1 μM for Bacillus velezensis SQR9. Chemotaxis assays with methyl-accepting chemotaxis proteins (MCPs) deletion strains demonstrated that McpA was solely responsible for chemotaxis towards D-galactose. Interestingly, D-galactose significantly enhanced the biofilm formation of SQR9 in an McpA-dependent manner. Further experiment showed that D-galactose also enhanced root colonization by SQR9. In addition, the secretion of D-galactose by cucumber roots could be induced by inoculation with SQR9, indicating that D-galactose may be an important signal in the interaction between plant and SQR9. These findings suggested that the root-secreted D-galactose was a signal, the secretion of which was induced by the beneficial bacteria, and which in turn induced colonization of the bacteria.