To investigate the effects of the endophyte Bacillus subtilisALB629 on the growth of cacao seedlings at early developmental stage and to evaluate its antimicrobial properties.Methods and Results:
Germinating cacao seeds were inoculated with ALB629, and seedlings growth was evaluated 30 days later. Significant increase (P < 0·05) was observed in the root system (up to 30%), leaf area (14%) and stem height (7·6%). ALB629 colonized the entire plant, prevailing over indigenous micro-organisms. In addition, it was tested in vitro, by pairing assays, and showed antagonistic effect against the phytopathogenic fungi Moniliophthora perniciosa, Colletotrichum sp. and C. gossypii. When tested in cacao-grafting procedure in the field, ALB629 increased the grafting success rate (24%), indicating its protective effect. In addition, this Bacillus secretes an antagonist compound, as shown by the antifungal activity of the cell-free culture.Conclusions:
Bacillus subtilisALB629 promotes cacao root growth, besides promoting growth of the aerial part of cacao seedlings. It has antimicrobial properties and produces an antifungal compound.Significance and Impact of the Study:
ALB629 presented beneficial characteristics for cacao cultivation, being a good biological control agent candidate. Furthermore, it is a potential source of antifungal compound with potential for commercial exploitation.