Bacillus velezensis stimulates resident rhizosphere Pseudomonas stutzeri for plant health through metabolic interactions

• Published in: The ISME Journal Vol. 16; no. 3; pp. 774 - 787
• Main Authors: Sun, Xinli, Xu, Zhihui, Xie, Jiyu, Hesselberg-Thomsen, Viktor, Tan, Taimeng, Zheng, Daoyue, Strube, Mikael L., Dragoš, Anna, Shen, Qirong, Zhang, Ruifu, Kovács, Ákos T.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2022; Nature Publishing Group
• Subjects: 101/58; 38/22; 38/23; 38/39; 38/77; 38/90; 38/91; 42/70; 45/22; 631/158/855; 631/326/171/1818; 631/326/2565; 631/326/41; 631/326/46; Amino acids; Bacillus - genetics; Bacillus - metabolism; Bacillus velezensis; Bacteria; Biofilms; Biological control; Biomedical and Life Sciences; Biosynthesis; Chain branching; Cooperation; Ecology; Evolutionary Biology; Genetic analysis; Genomes; Indigenous plants; Life Sciences; Metabolism; Metabolites; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microbiota; Microorganisms; Pellicle; Plant bacterial diseases; Plant growth; Plant Roots - microbiology; Pseudomonas; Pseudomonas stutzeri; Pseudomonas stutzeri - genetics; Rhizosphere; Soil Microbiology; Species; Transcriptomics; Trophic relationships
• ISSN: 1751-7362; 1751-7370
• DOI: 10.1038/s41396-021-01125-3

Trophic interactions play a central role in driving microbial community assembly and function. In gut or soil ecosystems, successful inoculants are always facilitated by efficient colonization; however, the metabolite exchanges between inoculants and resident bacteria are rarely studied, particularly in the rhizosphere. Here, we used bioinformatic, genetic, transcriptomic, and metabonomic analyses to uncover syntrophic cooperation between inoculant ( Bacillus velezensis SQR9) and plant-beneficial indigenous Pseudomonas stutzeri in the cucumber rhizosphere. We found that the synergistic interaction of these two species is highly environmental dependent, the emergence of syntrophic cooperation was only evident in a static nutrient-rich niche, such as pellicle biofilm in addition to the rhizosphere. Our results identified branched-chain amino acids (BCAAs) biosynthesis pathways are involved in syntrophic cooperation. Genome-scale metabolic modeling and metabolic profiling also demonstrated metabolic facilitation among the bacterial strains. In addition, biofilm matrix components from Bacillus were essential for the interaction. Importantly, the two-species consortium promoted plant growth and helped plants alleviate salt stress. In summary, we propose a mechanism in which synergic interactions between a biocontrol bacterium and a partner species promote plant health.