Inhibition des champignons phytopathogènes par Rhizobium

Abstract

This study was carried out to evaluate the antagonistic effect of ten isolated characterized Rhizobium sp. isolates and three referenced strains against aggressive fungi Fusarium., Aspergillus, Penicillium ,Alternaria, Humicola and Cladosporium. isolated from infected and wilted plants. The isolated Rhizobia were resistant to penicillin and amoxicillin with generation time ranged from1.9 to 6.4 h, they were able to grow temperatures from 4°C to 37°C, tolerate salt concentration (0.5–2%) and produce siderophores and proteases. The results demonstrated the effectiveness of the Rhizobia isolates and the referenced strains against the fungi isolates in vitro and in vivo. In dual culture, all Rhizobia isolates inhibited the mycelial growth of the pathogens. The best disease control was obtained with isolate F3 from faba bean which inhibited the fungal growth with more than70%. The highest inhibition growth was obtained against Alternaria spp.2, Penicillium spp.2, Cladosporium spp and Humicola spp. with an inhibition rate ranging from 90 to 96%. And with a percentage of 97% towards Fusarium spp.2.In pot experiments, Rhizobia isolates from chickpea, lentil and faba bean reduced significantly all disease incidence with more than 75%; where the best fight was observed in lentil plants, while in faba bean no wilted plants were observed. Seeds inoculated with Rhizobia and fungi in petri dishes showed that isolates from faba bean and lentil were the most effective in reducing fungi disease incidence