Development of a Quantitative PCR Assay for Quantification of Fusarium solani f.sp. phaseoli in Resistant and Susceptible White Bean

Bean root rot caused by soil pathogenic fungus, F.solani f.sp. phaseoli, is considered as one of the most important diseases of bean in the world and in Iran. At the moment use of resistant cultivars is the most effective method of control. For this reason, the response of five cultivars and 14 lines of white beans were evaluated to Fusarium root rot. Firstly, a morphological evaluation of disease symptoms and then real time PCR quantification were performed. Based on the results of morphological evaluation the KBC43106 line and cultivar Dorsa, were found to be sensitive and tolerant, respectively. For quantitative assessment and growth trend of the pathogen in sensitive and tolerant genotypes, the bean seedlings were inoculated by 107 suspension of relevant pathogen with root dip method, then DNA was extracted from root of inoculated and control seedlings at regular sampling intervals. The gradual increase in the amount of fungal DNA of roots was quantified by Real time PCR technique and utilizing of SYBR Green system with specific primers for elongation factor 1-α gene. The results showed that there is a significant difference between the amount of pathogen DNA in the roots of susceptible and tolerant plants, so Real time PCR technique is suitable for resistance screening of bean genotypes against Fusarium root rot.