Isolation of Bacillus strains from the rhizosphere of Tomato and their in vitro antagonistic effects against phytopathogenic fungi.

Nihorimbere Venant*, Kakana Pascal, Sindayigaya Ernest

Université du Burundi, Faculté d’Agronomie et de Bioingénierie, Département de Technologie agro alimentaire. B.P. 7268 Bujumbura, Burundi.

*Corresponding Author’s Email: venant.nihorimbere@gmail.com; 

Tel: + 257 77 817 830.

Accepted 20 February, 2013

Abstract

Bacillus strains were isolated from the rhizosphere of tomatoes to detect their biocontrol effects against phytopathogens. We determined in vitro activities of 44 native strains of Bacillus spp. isolated from the tomato rhizosphere against some fungi that are well known for their severe pathogenicity towards many economically important crops. The isolates were first evaluated for hydrolytic enzyme activities such as protease, chitinase and lipase after being screened for the in vitro antifungal activity. The culture on Glucose Yeast Peptone (GYP)-agar medium showed that among those strains, only 28, 3 and 11 isolates had respectively hydrolytic enzyme activities for protease, chitinase and lipase. In addition to enzymatic activities, these isolates were also found to have antagonistic activities against some phytopathogenic fungi, where four among them were selected to be strong inhibitors of at least two potent fungi tested. For strains identity, a complete identification based on molecular characterization and biochemical tests is on the way and further considerations are necessary to optimize soil microbial technology to the benefit of plant-growth and health in the natural environment.

Keywords: Bacillus, isolation, rhizosphere, screening, antagonism, fungi.