PHYLOGENETIC RELATIONSHIPS OF SOME PHYTOPATHOGENIC SCLEROTIAL FUNGI INFERRED FROM RIBOSOMAL DNA SEQUENCES AND MORPHOLOGICAL CHARACTERS

Abstract

Thirty eight fungal cultures were raised from 24 infected host plant species. These fungal cultures were categorized in to five groups based on their cultural and sclerotial characteristics. Group I, II, III, IV and V included 12, 9, 7, 5 and 5 isolates, respectively. The isolates of group I were identified as R. bataticola, group II as M. phaseolina, group III as R. solani, group IV as Sclerotium rolfsii and group V as Sclerotinia sclerotiorum. Sequences of internal transcribed spacer (ITS) region with 5.8S gene of sclerotial fungi resolved phylogenetic affinities with variable evolutionary rate. Parsimony analysis grouped three species R. solani, R. bataticola and Sclerotium rolfsii belonging to Basidiomycota together and M. phaseolina and S. sclerotiorum belonging to Ascomycota formed a separate group. R. solani and S. rolfsii were found to have affinities with the teleomorph genera. R. solani and R. bataticola taxa represent two distinct lineages. R. bataticola and M. phaseolina showed the maximum similarity based on ITS 5.8S gene sequences but INDELS show variation which validate independent evolutionary lineage. Study revealed new insights into phylogenetic relationship of sclerotial species useful in assessing fungicide application strategies for disease management.