Genetic Variability of Macrophomina phaseolina Isolates from Dry Beans in Turkey

Abstract

Charcoal rot is a soil and seed borne, economically important fungal disease on dry bean in Turkey. Twenty bean isolates of M. phaseolina collected from different locations in Turkey during 2008 and 2012 years were studied for genetic variability using random amplified polymorphic DNA (RAPD) assay, chlorate sensitivity on medium supplemented with 120mM of potassium, phenotype of colony, and pathogenicity. Isolates were identified as M. phaseolina based on morhological features and PCR assays using species-specific primers (MPKF1and MPKR1). Isolates of M. phaseolina were analysed for their aggressiveness on the susceptible bean cv. Akman 98, by soil inoculation method. Isolates exhibiting a dense chlorate phenotype were chlorate-resistant, while those possessing feathery and restricted chlorate phenotypes were chlorate-sensitive. More than half of the isolates (55%) were resistant to chlorate and produced dense phenotype, while 35% isolates showed feathery and two isolates (10%) showed restricted growth. DNA from 20 isolates was subjected to genetic diversity analysis by the RAPD method using 14 randomly chosen 10-base random primers, and low genetic diversity (33.3%) was observed among the tested isolates.