Functional Analysis and Genome Mining Reveal High Potential of Biocontrol and Plant Growth Promotion in Nodule-Inhabiting Bacteria Within Paenibacillus polymyxa Complex

• Published in: Frontiers in microbiology Vol. 11; p. 618601
• Main Authors: Ali, Md Arshad, Lou, Yang, Hafeez, Rahila, Li, Xuqing, Hossain, Afsana, Xie, Ting, Lin, Li, Li, Bin, Yin, Yanni, Yan, Jianli, An, Qianli
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 18.01.2021
• Subjects: endophyte; fusaricidin; Fusarium; Microbiology; nitrogen fixation; plant growth promoting rhizobacteria; Fusarium; fusaricidin; endophyte; nitrogen fixation; plant growth promoting rhizobacteria
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2020.618601

Bacteria belonging to the genus were frequently isolated from legume nodules. The nodule-inhabiting as a resource of biocontrol and plant growth-promoting endophytes has rarely been explored. This study explored the nodule-inhabiting ' antifungal activities and biocontrol potentials against broad-spectrum important phytopathogenic fungi. We collected strains which were isolated from nodules of , , , , , or and belong to , , , , , , or closely related to , or . These nodule-inhabiting showed diverse antagonistic activities against five phytopathogenic fungi ( , , , , and ). Six strains within the complex showed broad-spectrum and potent activities against all the five pathogens, and produced multiple hydrolytic enzymes, siderophores, and lipopeptide fusaricidins. Fusaricidins are likely the key antimicrobials responsible for the broad-spectrum antifungal activities. The nodule-inhabiting strains within the complex were able to epiphytically and endophytically colonize the non-host wheat plants, produce indole acetic acids (IAA), and dissolve calcium phosphate and calcium phytate. strains RP20, RP51, and RP62 could fix N . RP51 and sp. RP31, which showed potent plant colonization and plant growth-promotion competence, effectively control fungal infection . Genome mining revealed that all strains ( = 76) within the complex contain gene encoding indole-3-pyruvate decarboxylase for biosynthesis of IAA, 96% ( = 73) contain the cluster for biosynthesis of fusaricidins, and 43% ( = 33) contain the cluster for nitrogen fixation. Together, our study highlights that endophytic strains within the complex have a high probability to be effective biocontrol agents and biofertilizers and we propose an effective approach to screen strains within the complex.