Exploring the properties of chitinolytic Bacillus isolates for the pathogens biological control.

Plant fungal diseases generate serious losses in the agriculture. The bacteria producing biologically active substances that inhibit the growth of fungal pathogens can be an alternative to the chemicals. The chitinolytic bacteria were isolated from the rhizosphere of wheat (Triticum aestivum L.) and their physiological properties which may be useful in the promotion of plant growth have been investigated. Their chitinases and antifungal activity were studied. The isolates were also tested for indirect growth-promoting traits such as ammonia production, siderophore production, hydrogen cyanide production, and salicylic acid production. Two chitinolytic strains B3 and B5 were identified as Bacillus subtilis and Bacillus sp., respectively. They produced active chitinases on a medium containing shrimp shell powder. The purified chitinases having the molecular weight of 35-45 kDa inhibited the growth of important plant pathogens such as Alternaria alternata, and Fusarium oxysporum. Additionally, the isolates showed the ability to produce a broad range of biological substances promoting the growth of plants.