Siderophore‐like activities inRhizobium phaseoli

Abstract
Nineteen out of fifty‐two strains of R. phaseoli showed siderophore‐like activity when bioassayed against Xanthomonas campestris pv. phaseoli CBP123 (CBP123) and Pseudomonas, syringae pv. phaseolícola (Psp) in minimum and minimum without FeCl3 media. The inhibitory activities of the strains of R. phaseoli were rather specific due to the fact that 50% of inhibition or more was found in 36.6% of the cases of twelve strains of Rhizobium assayed, in as many as 61.3% of the pathogenic strains of Phaseolus vulgaris: CBP123 and Psp, in 16.8% of seven bacterial strains non‐phytopathogenicaly related to the plant P. Vulgaris, whereas only in 6.8% of the cases of two strains that affect animals. The twentyfold concentrated spent media from two R. phaseoli strains diminished the necrotic and chlorotic damages caused by CBP123 and Psp on the leaves of plants of P. vulgaris in the greenhouse.