Mycorrhizal and endophytic fungal association in Paphiopedilum druryi (Bedd.) Stein - A strict endemic and critically endangered orchid of the Western Ghats

Abstract

Abstract Mycorrhizal and non-mycorrhizal endophytes of Paphiopedilum druryi (Bedd.) Stein a critically endangered terrestrial orchid were isolated and identified through root and stem segments, for the first time. Molecular sequencing with internal transcribed spacer (ITS) regions (ITS 1 and ITS 4) and nuclear large sub unit (LSU) ribosomal DNA (rDNA) primers (LR7 and LROR) were primarily used to identify the fungal association. Three culturable fungi from each plant segments were isolated within 3 weeks of incubation in dark. Culture characteristics of the isolates provide minuscule differences among the isolates, while the sequences of LSU markers confirmed three distinct species namely Tulasnella calospora, Penicillifer martinii and Colletotrichum sp. The rate of fungal isolation from the root sample was 0.27 and the stem sample was 0.23. The overall colonization rate of each sample was 20%. Colletotrichum sp. and Penicillifer martinii are commonly recorded as pathogenic to a wide range of crops including grasses, whereas Tulasnella calospora has been identified as a beneficial saprotrophic fungus associated with several orchids to form mycorrhizal association.