Caractérisation du potentiel antagoniste de la flore Bacillus rhizosphérique vis - à- vis des phytopathogènes

Abstract

Plant growth-promoting bacteria (PGPR) represent a part of rhizobacteria that have the capacity to promote plant growth and can improve plant performance and tolerance to environmental stresses. In this work, we studied the potential of rhizospheric bacteria of the Bacillus flora on some phytopathogens. A total of 33 Bacillus isolates were isolated from the rhizospheres of eight 8 samples grown at Ain Safsaf and Achaachad in the wilaya of Mostaganem. After isolating the rhizobacteria, they were tested to assess their antagonistic activity against phytopathogens and some PGP activities. Analysis of the results showed that seven bacterial isolates (LD2, LB1, LC1, LA4b, LA5, LB7 and LD1) had antifungal activity against some phytopathogens. Two isolates formed a transparent halo around the colonies, indicating phosphate solubilization on PVK medium with solubilization indices of 2.25 and 2.14 respectively. Among the bacterial isolates tested, 16 isolates produced indole acetic acid (IAA) at concentrations ranging from 7.87ug/ml to 54.76ug/ml, 12 isolates were able to hydrolyze cellulose, 22 isolates were positive for amylase production, and no isolate was able to produce the pectinase. The results obtained suggest that these isolates could be used to reduce the impact of plant pathogens.