Genetic Diversity of Gaeumannomyces graminis var. tritici Populations Using RAPD and ERIC Markers

Abstract

Take-all disease which is caused by Gaeumannomyces graminis var. tritici (Ggt) is the most damaging root disease of wheat. Twenty four isolates of pathogen were recovered from diseased samples collected from different provinces of Iran including Fars, Markazi, and Mazandaran. All isolates were specifically identified as Ggt and simultaneously divided into two subpopulations of A and B types. Five primers of RAPD and ERIC primer pair were used to determine the DNA polymorphisms. Cluster analysis was noticed that with the exception of OPC-08 primer, the all remaining RAPD primers and ERIC separated T-28 (having both simple and lobed hyphopodia) from other Ggt isolates with simple hyphopodia. Additionally, these primers identified and separated the two varieties of the pathogen, Gaeumannomyces graminis var. graminis (Ggg) and Ggt. Polymorphism Information Content (PIC) value was estimated between 0.23-0.3. The tested isolates were divided into three groups including a single member group housed T-28 isolate at 39.5% similarity. All Ggt isolates with simple hyphopodia can be divided into two groups, the first group from Markazi province with a 12.5% frequency consisting of three isolates including two B-types (T-1, T-9) that also separated by Principle Component Analysis (PCA). The second group (A-type) contained 83.3% of the remaining isolates. The Iranian population of Ggt shows a high level of genetic diversity dominated by A-type. The dominant population of Ggt isolates provides the pathogen with the ability to fight or overcome any commonly used control measures such as chemicals or resistant cultivars.