First report of hyperparasitic Ramularia coleosporii from plumeria leaf rust in Sri Lanka

In this study, we report the first instance of the fungus Ramularia coleosporii, isolated in the sori of Plumeria leaf rust caused by Coleosporium plumeriae in Sri Lanka. The fungus R. coleosporii was cultured on potato dextrose agar (PDA) medium, DNA was isolated, and PCR was conducted targeting the internal transcribed spacer region (ITS) of the genome. Phylogenetic analysis using the obtained sequence data and other homologous sequences retrieved from GenBank revealed a close relationship with Ramularia coleosporii strains reported from Eastern and Western regions of Asia. The Sri Lankan isolate showed 99% sequence identity with R. coleosporii from South Korea, with strong bootstrap support (99%) for this identification. Although R. coleosporii has been reported as a hyperparasite of plumeria rust in other regions, hyperparasitism was not experimentally verified in this study.