Pseudomonas forestsoilum sp. nov. and P. tohonis biocontrol bacterial wilt by quenching 3-hydroxypalmitic acid methyl ester

Si Wang; Ming Hu; Huilin Chen; Chuhao Li; Yang Xue; Xinyue Song; Yuqing Qi; Fan Liu; Xiaofan Zhou; Lian-Hui Zhang; Jianuan Zhou

doi:10.3389/fpls.2023.1193297

Pseudomonas forestsoilum sp. nov. and P. tohonis biocontrol bacterial wilt by quenching 3-hydroxypalmitic acid methyl ester

Front Plant Sci. 2023 Jun 30:14:1193297. doi: 10.3389/fpls.2023.1193297. eCollection 2023.

Authors

Si Wang¹, Ming Hu¹, Huilin Chen¹, Chuhao Li¹, Yang Xue¹, Xinyue Song¹, Yuqing Qi¹, Fan Liu¹, Xiaofan Zhou¹, Lian-Hui Zhang¹, Jianuan Zhou¹

Affiliation

¹ National Key Laboratory of Green Pesticide, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China.

Abstract

Bacterial wilt caused by Ralstonia solanacearum ranks the second top important bacterial plant disease worldwide. It is also the most important bacterial disease threatening the healthy development of Casuarina equisetifolia protection forest. 3-hydroxypalmitic acid methyl ester (3-OH PAME) functions as an important quorum sensing (QS) signal regulating the expression of virulence genes in R. solanacearum, and has been regarded as an ideal target for disease prevention and control. To screen native microorganisms capable of degrading 3-OH PAME, samples of C. equisetifolia branches and forest soil were collected and cultured in the medium containing 3-OH PAME as the sole carbon source. Bacteria with over 85% degradation rates of 3-OH PAME after 7-day incubation were further separated and purified. As a result, strain Q1-7 isolated from forest soil and strain Q4-3 isolated from C. equisetifolia branches were obtained and identified as Pseudomonas novel species Pseudomonas forestsoilum sp. nov. and P. tohonis, respectively, according to whole genome sequencing results. The degradation efficiencies of 3-OH PAME of strains Q1-7 and Q4-3 were 95.80% and 100.00% at 48 h, respectively. Both strains showed high esterase activities and inhibited R. solanacearum exopolysaccharide (EPS) and cellulase production. Application of strains Q1-7 and Q4-3 effectively protects C. equisetifolia, peanut and tomato plants from infection by R. solanacearum. Findings in this study provide potential resources for the prevention and control of bacterial wilt caused by R. solanacearum, as well as valuable materials for the identification of downstream quenching genes and the research and development of quenching enzymes for disease control.

Keywords: 3-hydroxypalmitic acid methyl ester; Pseudomonas; Ralstonia solanacearum; bacterial wilt; quorum quenching.

Grants and funding

This research was sponsored by grants from the Guangdong Forestry Science and Technology Innovation Project (2020KJCX009), the Key-Area Research and Development Program of Guangdong Province (2018B020205003), the College Students’ Innovative Entrepreneurial Training Plan Program (S202210564160), and the China Scholarship Council Fellowship Program (202108440367).