Taxonomy and molecular phylogeny of Inonotus rickii from Southern India

Abstract

Inonotus rickii is cosmopolitan in distribution that considered being one of the most economically important hymenocheatoid fungi causing canker, white rot on forest trees and several ornamental trees growing in urban settings. In the present investigation, 17 isolates collected from urban and wild trees were analysed by morphotaxonomy, cultural and molecular methods. I. rickii has very distinct macro-microscopic characters that hardly produce basidiomes but anamorphic stage was more frequent with a distinctly golden yellowish buff. Microscopically, both anamorph and telomorph shows abundant, thick walled brownish chlamydospores of irregular shape and setal hyphae. Phylogenetic analysis of ITS rDNA region showed that the they formed a main lineage with two well resolved clades; the isolates of anamorph stage of I. rickii from Europe, Argentina, China, Nepal and India  grouped together in a single clade with our Southern Indian isolates, whilst the isolates from Florida were clearly divergent from the others isolates. The 17 bp insert in the anamorphic stage from Asian isolates and ca. 48 bp insertion in the Telomorph of Eurasian- south American collections with the American collections (which lacks 65 bp insertion) revealed the polymorphism in the ITS 1 region and has influenced the grouping in the phylogenetic tree construction.