Morpho-molecular characterization of Ceratobasidium sp.: A mycorrhizal fungi isolated from a rare epiphytic orchid Gastrochilus calceolaris (J. E. Sm.) D. Don

摘要

A mycorrhizal fungus, Ceratobasidium sp. GC (NCBI Gene Bank Accession nonbsp;GQ369961) associated with the roots of an epiphytic orchid Gastrochilus calceolaris wasnbsp;investigated by cultural morphology, microscopic features and molecular analysis ofnbsp;Internal Transcribed Spacer (ITS) regions sequences of nuclear ribosomal DNA. Thenbsp;colony appearance of the fungal endophyte was fluffy growth pattern and the colour ofnbsp;the young colony was milky white on both surfaces that turned in to brown at maturity onnbsp;the upper surface and deep brown on reverse surface. The microscopic features of thenbsp;fungus i.e. hyphal diameter, multi-nucleate vegetative cells, right angle branching patternnbsp;with slight constriction at branching point and a dolipore septum near the branching pointnbsp;were observed. All the characters corroborated the identity with anamorphic Rhizoctonianbsp;like fungi. The ITS regions sequences of nrDNA and phylogenetic analysis based on thenbsp;neighbor-joining method showed clustered with Rhizoctonia like fungi, and thenbsp;maximum identity (98.28%) with Ceratobasidium RR and Ceratobasidium FPUBnbsp;isolated from Rhynchostylis retusa and Dactylorrhiza hetagera, respectively. Thus, thenbsp;ITS of nrDNA sequences validated the morphological data. This is the first report ofnbsp;orchid mycorrhizal fungi from Bangladesh.