Anastomosis grouping and phylogenetic analysis of Rhizoctonia isolates on wheat in Türkiye

This study aims to determine the species and evaluate the genetic diversity of the pathogenic and nonpathogenic Rhizoctonia spp. and anastomosis groups (AG) from wheat plants and rhizosphere soils in Turkey. Rhizoctonia species were isolated from plants and rhizosphere soils in wheat fields in 5 provinces in the Central Anatolian Region of Türkiye. As a result of the isolations, a total of 88 multinucleate (MN) and binucleate (BN) Rhizoctonia isolates were obtained. Identifications of the isolates were determined by rDNA-ITS sequence analyses. The identified isolates belonged to MN Waitea circinata var. zeae, W. circinata var. oryzae, W. circinata var. circinata, MN Rhizoctonia solani AG 2-1, AG 2-2, AG 3, AG 4-HGII, AG 4-HGIII, AG 5, AG 8, AG 11 and BN AG A, AG DI, AG E, AG G, AG H, AG I, AG I-like and AG K. The most isolated group was W. circinata var. circinata. In the pathogenicity studies, the most virulent group was determined as R. solani AG 4. Among the binucleate isolates, groups other than R. cerealis AG DI were not found to be pathogenic. Neighbor-joining phylogenetic trees of isolates were constructed from rDNA-ITS sequences. As a result of this study, the regional distribution of MN and BN Rhizoctonia AG isolates in important wheat production areas in the Central Anatolia Region, Türkiye was determined. In addition, this study is the first comprehensive study in which the genetic diversity of Rhizoctonia AGs isolates obtained from wheat and rhizosphere soils in the region was evaluated with a molecular approach.