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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.02727

Oxalic acid from Sesbania rostrata seed exudates mediates the chemotaxis response of Azorhizobium caulinodans ORS571 using multiple strategies

 Xiaolin Liu1, 2, Kaiye Zhang2, 3,  Zhihong Xie2* and  Chengsheng Zhang4
  • 1University of Chinese Academy of Sciences, China
  • 2Key Laboratory of Coastal Biology and Biological Resources Utilization, Yantai Institute of Coastal Zone Research Chinese Academy of Sciences, China
  • 3Shanxi Agricultural University, China
  • 4Tobacco Research Institute (CAAS), China

Chemotaxis towards seed exudates is important in the establishment of microbe-plant associations. The objective of this work was to explore if organic acids from seed exudates of Sesbania rostrata play a role in recruiting Azorhizobium caulinodans ORS571 in the plant rhizosphere. High performance liquid chromatography (HPLC) was used to analyze the organic acids content in seed exudates of S. rostrata and to further determine their roles in A. caulinodans growth and chemotactic response. Succinic, acetic, citric, oxalic, and lactic acids were the most abundant, and except for oxalic acid, they could support A. caulinodans growth as a sole carbon source. TlpA1, a transmembrane chemoreceptor was found to be involved in the chemotactic response to these organic acids. Oxalic acid had a direct role in the chemotactic response, but it also had an indirect role by promoting or inhibiting the chemotaxis response towards other chemoeffectors. Furthermore, the indirect role of oxalic acid on other chemoeffectors was concentration dependent. The effect of oxalic acid at different concentrations on the host root colonization was also determined. By using different strategies, oxalic acid appears to play a major role in early steps of the association of A. caulinodans and its host plant.

Keywords: organic aicds, Chemotaxis, Plant Exudates, colonization, Oxalic Acid

Received: 08 Aug 2019; Accepted: 08 Nov 2019.

Copyright: © 2019 Liu, Zhang, Xie and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Zhihong Xie, Key Laboratory of Coastal Biology and Biological Resources Utilization, Yantai Institute of Coastal Zone Research Chinese Academy of Sciences, Yantai, Shandong Province, China, zhxie@yic.ac.cn