USE OF SOME STREPTOMYCES SPECIES AS BIO-AGENTS TO CONTROL BEAN WHITE ROT DISEASE CAUSED BY Sclerotinia sclerotiorum

Abstract

Bean is subject to several soilborne pathogenic fungi that affect its growth and production. Field observation revealed that the most common symptoms on naturally infected bean plants in Ibsheway (Ebshawai) Province, Fayoum Governorate, Egypt were characteristic white cotton-like mycelium on stems, petioles, and leaves, then exhibited water-soaked lesions and sclerotia were formed on the infected pods. The results of this study could be summarized as the following: 1- The aforementioned symptoms were suspected of being caused by Sclerotinia sclerotiorum and confirmed to be so by the culturing onto the slant tubes Cook's medium. 2- The fungus was identified biologically and molecularly. Based on symptomology and disease severity in the greenhouse, pathogenicity tests were performed and proved that the isolate was pathogenic to bean plants cv. Paulista giving the typical expected disease symptoms. 3- Molecular identification was performed polymerase chain reaction (PCR) amplification and nucleotide sequencing was used to detect and characterize the pathogen using the universal primers (ITS-1 and ITS-4). PCR amplification with the primers (ITS-1/ITS-4) resulted in an approximately 553-bp product within the internal transcribed spacer (rDNA-ITS) region of the fungal isolate tested. The sequence of this isolate was submitted to NCBI GenBank and gave an accession number MT645495.