Detection of Pythium porphyrae infecting Philippine Pyropia acanthophora based on morphology and nuclear rRNA internal transcribed spacer sequences

Abstract

Outbreaks of Pythium porphyrae, a fungus that causes red rot disease can devastate nori production, but studies have focused on the occurrence of P. porphyrae from cultivated hosts compared with the wild ones. An unexpected encounter of P. porphyrae infecting the wild nori seaweed, Pyropia acanthophora, collected from the Philippines prompted the present study. The definitive morphological diagnoses of P. porphyrae infection based from the previous reports were similar to those obtained here. Phylogenetic and haplotype analyses of nuclear rRNA internal transcribed spacer sequences confirmed that the pathogen infecting the Philippine Py. acanthophora can be assigned to P. porphyrae.