Multifaceted intervention of Bacillus spp. against salinity stress and Fusarium wilt in tomato

AIM: This study aimed to screen halotolerant Bacillus strains able to promote growth and protect tomato plants against salt stress and Fusarium wilt (Fusarium oxysporum f. sp. lycopersici). METHODS AND RESULTS: ) was also evaluated. Compared to control plants, aboveground dry weight increased in plants inoculated with AP-6, AP-85, AP-3, AP-100 and QST-713 strains developed in the absence of salt stress. The same tendency occurred for root dry weight; however, AP-3 strain was more effective, promoting an increase of 163%, when compared to control. Chlorophyll index and height increased >40 and 53%, respectively, for all Bacillus strains. Saline stress reduced plant growth regardless of the presence of Bacillus. Height, stem diameter, and aboveground and root dry weights increased in plants treated with Bacillus strains grown under saline conditions when compared to control. Bacillus velezensis AP-3 reduced the severity of Fusarium wilt in tomato by 50% when compared to control. CONCLUSION: Halotolerant Bacillus strains controlled tomato Fusarium wilt, increased growth as well as tolerance to salt stress. SIGNIFICANCE AND IMPACT OF THE STUDY: We demonstrated the efficacy of halotolerant Bacillus strains to control Fusarium wilt and improve tomato growth. We also demonstrated that these Bacillus strains protect tomato plants against salt stress. Bacillus can be used in an eco-friendly way because they are considered Generally Recognized As Safe.