Hamidreza Alizadeh

Botrytis is one of the most common and harmful plant pathogens in the world and has been reported in all climates. Species of this genus cause economic damage to crop yield in fields and greenhouses and is known as important post-harvest pathogens for various crops. In this study, the biocontrol effects of 10 bacterial isolates against Botrytis cinerea was investigated. The results showed that two isolates of Pseudomonas fluorescens, one isolate of Bacillus subtilis, and one isolate of Bacillus velezensis, were able to reduce the growth of pathogen in inhibition zone test. The largest diameter of the inhibition zone was related to isolate Bacillus subtilis UJB 33. These four isolates did not produce any volatile compounds. However, they were able to produce the enzymes protease, amylase, and cellulase. Isolates Bacillus velezensis UJB 20, Bacillus subtilis UJB 33, and Pseudomonas fluorescens UJB 13 also produced surfactants, and isolates Pseudomonas fluorescens UJB 28 and Bacillus subtilis UJB 33 produced hydrogen cyanide. It is likely that the ability of these four isolates to prevent the growth of Botrytis is due to the effect of these secondary metabolites. Proteases, amylases, and cellulases can damage the cell walls and cell membranes of the fungus, and surfactants can affect the osmotic balance of the fungus. These results suggest these isolates of bacteria have the potential for biological control of Botrytis cinerea