Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
On the basis of preliminary in vitro screening tests, a competent strain of Pantoea agglomerans ENA1 (P. agg. ENA1) recovered from soybean nodule was evaluated for its antagonistic activity against Macrophomina phaseolina causal agent of charcoal rot of soybean. The results of various in vitro assays showed that P. agg. ENA1 is capable of exerting strong antagonistic effect against M. phaseolina inhibiting its mycelial growth up to 89% as compared to control. The results showed a significant reduction of the disease as measured in host-plant weight increase, reduced microsclerotial coverage of the host tissues and decreased population of the pathogen in soil. Soils treated with the antagonist in presence of the pathogen resulted in 40% increase in aerial fresh weight and 63% decrease in root and stem surface covered by microsclerotia as compared with control. Furthermore, a significant decrease in the pathogen population ranging from 73 to 76% was observed in sterile and non-sterile soils, respectively. P. agg. ENA1 is suggested as a potent biocontrol agentthat provides excellent rhizosphere colonization and control of M. phaseolina