Characterization of Bacillus and its lipopeptides for controlling fungal phytopathogens and enhancing agriculture output

Abstract

The agricultural productivity loss due to microbial phytopathogens has been a serious global issue. The present study was designed to evaluate soil-borne Bacillus strains for their biocontrol potential against various important fungal pathogens and for promoting plant growth. The bioactivity and PGPR profile of isolated Bacillus strains (MQ7 and MQ8) was determined against Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Fusarium oxysporum using different in vitro techniques. Crude antifungal metabolites were extracted from the Bacillus MQ7 and MQ8 were characterized using FT-IR. Finally, green greenhouse experiments were conducted on the Zea maize plant to assess the antifungal and PGPR activity of Bacillus strains and their comparison with commercially available fungicides (Pyranazole and Fosetyl Aluminium). The results indicated that the strain MQ7 exhibited excellent anti-fungal activity against Aspergillus flavus, Aspergillus niger and Fusarium oxysporum with inhibitory zones of 55mm, 56mm and 23mm respectively. In the case of strain MQ8, 35mm, 48mm, and 35mm of the zones were recorded for the aforementioned fungal isolates. The antifungal activity of the Bacillus strain MQ7 was comparatively higher than the strain MQ8 i.e. 50%±0.5 for F. oxysporum, and for A. flavus 28.71%±0.25. In-vivo experiments on Zea maize showed increase in plant growth up to 10.13% and 5.8% in the presence of strain MQ7 and MQ8 respectively, in comparison to the positive control. Based on the results, it can be concluded that Bacillus strains MQ7 and MQ8 can produce secondary metabolites with excellent antifungal activity and suppress the incidence of fungal infections under greenhouse conditions. In addition, the aforementioned strains effectively enhanced the growth of the Zea maize plants. Therefore, the Bacillus MQ7 and MQ8 could be effective biological resources as alternative biopesticides and biofertilizers and an important tool for sustainable agriculture.