Antifungal activity of bacterial strains from maize silks against Fusarium verticillioides.

Fusarium verticillioides is pathogenic to maize and mycotoxin-producer, causing yield losses, feed and food contamination, and risks to human and animal health. Endophytic (ISD04 and IPR45) and epiphytic (CT02 and IM14) bacteria from maize silks were tested in vitro and greenhouse against F. verticillioides and for hydrolytic enzyme production (cellulase, pectinase, protease, lipase, and chitinase). The strains preliminarily identified as Achromobacter xylosoxidans (ISD04), Pseudomonas aeruginosa (IPR45), and Bacillus velezensis (CT02 and IM14) by 16S gene sequencing. All strains showed antifungal activity in vitro with inhibition values from 58.5 to 100%; they changed hyphae morphology and inhibited the conidial germination by up to 100% (IPR45). The four strains produced at least one enzyme with antifungal activity. The microbiolized seeds reduced the fungal development in stored grains and stalk rot severity in the greenhouse by 72.6% (ISD04). These results highlight the potential of these strains as biocontrol agents against F. verticillioides.