Molecular identification of Tilletia controversa and T. caries, the causal agent of wheat dwarf and common bunt

Common and dwarf bunt of wheat are recognized as being caused by three closely related species, Tilletia caries and T. laevis as common bunt, and T. controversa as dwarf bunt. The morphological characteristics of two species including T. controversa and T. caries were studied from wheat grown in two provinces of Iran, Lorestan and Chaharmahal–o-Bakhtiari during 2014-2015. In this study, morphological characters could not completely distinguish these pathogens, as in some properties, they showed similarity to T. laevis. So, a collection of twenty wheat bunt isolates was used to compare species in morphological characteristics and phylogenetic relationships. Phylogenetic analyses were presented based on three PCR amplified nuclear DNA fragments including elongation factor 1 alpha (EF1α), the second largest subunit of RNA polymerase II (RPB2) genes and ITS-rDNA region. Maximum likelihood (ML) method was used to determine the phylogenetic relationship among isolates using MEGA v.6 and BEAUti and BEAST v1.6.1 software. Maximum likelihood bootstrap (BS) values and Bayesian posterior probabilities (PP) values were applied as criteria for strongly supported clades. Two species including T. controversa and T. caries were distinguished as different species with DNA sequence information.