Biological Control of Botrytis cinerea by Bacillus sp. Strain S7LiBe Under Abiotic Stress

Abstract

In this investigation, the isolate S7LiBe isolated from trefoil rhizosphere in Barbacha, Bejaia (northern Algeria), was selected on the basis of plant growth promoting attributes. This isolate identified as Bacillus sp. based on 16SrDNA sequence analysis, exhibits the highest similarity of 99.1% with Bacillus pichinotyi AF519463 andAF519460 and Bacillus sp. JX152775. Bacillus sp. S7LiBe has been subjected to the study of its antifungal activity against Botrytis cinerea in vitro and in vivo on the detached lettuce leaves. The effect of some abiotic factors on the performance of this bacterial strain as biocontrol agent and the production of some antifungal metabolites (siderophores, ammonia, hydrogen cyanide and chitinase) were also carried out. The results showed that Bacillus sp. S7LiBe strain inhibit the mycelial growth in high level (70%±1,33) and the fungal spores germination (82,54%±3,58 ). The strain produce siderophores, ammonia, hydrogen cyanide and chitinase. Its antagonistic activity was found to be optimal on CZA modified medium at a pH of 6.5 and a temperature of 30 ° C. The antagonist activity on the detached lettuce leaves showed that the bacterial strain inhibit 57.0% of the lesion extension.