College of Life Sciences, Guizhou University, 550025, Guiyang, Guizhou, China.
BMC Microbiol. 2023 Mar 30;23(1):85. doi: 10.1186/s12866-023-02818-9.
Burkholderia pyrrocinia strain P10 is a plant growth-promoting rhizobacterium (PGPR) that can substantially increase peanut growth. However, the mechanisms and pathways involved in the interaction between B. pyrrocinia P10 and peanut remain unclear. To clarify complex plant-PGPR interactions and the growth-promoting effects of PGPR strains, the B. pyrrocinia P10 transcriptome changes in response to the peanut root exudate (RE) were elucidated and the effects of RE components on biofilm formation and indole-3-acetic acid (IAA) secretion were analyzed.
During the early interaction phase, the peanut RE enhanced the transport and metabolism of nutrients, including carbohydrates, amino acids, nitrogen, and sulfur. Although the expression of flagellar assembly-related genes was down-regulated, the expression levels of other genes involved in biofilm formation, quorum sensing, and Type II, III, and VI secretion systems were up-regulated, thereby enabling strain P10 to outcompete other microbes to colonize the peanut rhizosphere. The peanut RE also improved the plant growth-promoting effects of strain P10 by activating the expression of genes associated with siderophore biosynthesis, IAA production, and phosphorus solubilization. Additionally, organic acids and amino acids were identified as the dominant components in the peanut RE. Furthermore, strain P10 biofilm formation was induced by malic acid, oxalic acid, and citric acid, whereas IAA secretion was promoted by the alanine, glycine, and proline in the peanut RE.
The peanut RE positively affects B. pyrrocinia P10 growth, while also enhancing colonization and growth-promoting effects during the early interaction period. These findings may help to elucidate the mechanisms underlying complex plant-PGPR interactions, with potential implications for improving the applicability of PGPR strains.
伯克霍尔德氏菌 P10 菌株是一种能显著促进花生生长的植物促生根际细菌（PGPR）。然而，伯克霍尔德氏菌 P10 与花生之间的相互作用涉及的机制和途径仍不清楚。为了阐明复杂的植物-PGPR 相互作用和 PGPR 菌株的促生作用，解析了伯克霍尔德氏菌 P10 对花生根分泌物（RE）响应的转录组变化，并分析了 RE 成分对生物膜形成和吲哚-3-乙酸（IAA）分泌的影响。
在早期的相互作用阶段，花生 RE 增强了包括碳水化合物、氨基酸、氮和硫在内的营养物质的运输和代谢。虽然鞭毛组装相关基因的表达下调，但参与生物膜形成、群体感应以及 II、III 和 VI 型分泌系统的其他基因的表达水平上调，从而使 P10 菌株能够与其他微生物竞争定植在花生根际。花生 RE 还通过激活与铁载体生物合成、IAA 产生和磷溶解相关的基因表达，增强了 P10 菌株的促生作用。此外，有机酸和氨基酸被鉴定为花生 RE 的主要成分。此外，P10 菌株的生物膜形成受苹果酸、草酸和柠檬酸诱导，而 IAA 分泌则受花生 RE 中的丙氨酸、甘氨酸和脯氨酸促进。
花生 RE 对伯克霍尔德氏菌 P10 的生长有积极影响，同时在早期相互作用期间增强了定植和促生作用。这些发现可能有助于阐明复杂的植物-PGPR 相互作用机制，为提高 PGPR 菌株的适用性提供了依据。
