Mating type distribution, genetic diversity and population structure of Ascochyta rabiei, the cause of Ascochyta blight of chickpea in western Iran

Abstract

Ascochyta blight (caused by Ascochyta rabiei) is an important disease of chickpea. Mating type distribution, genetic diversity and population structure A. rabiei isolates from western Iran, using specific matting type primers, and ISSR and SSR molecular markers. Two mating types were identified, with the 57% of isolates belonging to MAT1-1. Ten ISSR markers produced 78 polymorphic bands with an average polymorphism information content (PIC) value of 0.33. Seven SSR markers showed high allelic variation (four to seven alleles) with the average PIC value of 0.61. The generated dendrogram using neighbor joining approach with ISSR and SSR marker data grouped isolates in three clusters. Combined dendrogram and model-based population structure analysis divided the isolates into two distinct populations. No significant correlation was found between geographical origins of isolates and their genetic diversity patterns, although the isolates from North Kermanshah and Kurdistan were closely grouped, and most of isolates from Lorestan and Kermanshah were clustered in a separate group. This relative spatial correlation between geographical locations and A. rabiei grouping indicated high genetic diversity within populations and no significant gene flow between distinctly geographical regions. This suggests the nece0ssity of continuous monitoring of A. rabiei populations in order to design effective chickpea breeding strategies to control the disease.