Molecular detection and characterization of Sclerotium rolfsii Sacc. causing wheat foot rot isolated from northern Karnataka, India

Wheat foot rot disease is caused by Sclerotium rolfsii Sacc., a soil-inhabiting pathogen with a broad host range. In wheat, this pathogen causes blighted appearance and death. Studies on this organism have been performed mainly on morphological, physiological and pathogenic variability, but molecular diversity analysis based on the internal transcribed spacer (ITS) region of isolates collected from different wheat growing areas of Karnataka has not been attempted. ITSs are widely used for molecular detection and species identification. In this study, the DNA sequence of the region amplified by the ITS5 and ITS4 primer pair was used to detect five isolates of S. rolfsii collected from different agro-climatic zones of Karnataka. BLAST analysis of the aligned ITS5/4 sequences of the five isolates showed sequence homology with other Athelia rolfsii (teleomorph of S. rolfsii) sequences reported on other crops, while no previous sequences have been reported from wheat. Phylogenetic relationships across these isolates were analyzed and showed significant variability between the isolates by grouping them into two clades. To our knowledge, this is the first report of a molecular sequence of Sclerotiumrolfsii infecting wheat.

Automated summary

This study reports for the first time the molecular sequence of Sclerotium rolfsii infecting wheat, and reveals significant variability among isolates collected from different wheat growing areas in Karnataka. Phylogenetic analysis grouped the isolates into two clades based on ITS5/4 sequences.