Ceratobasidium orchid mycorrhizal fungi reveal intraspecific variation and interaction with different nutrient media in symbiotic germination of Prasophyllum (Orchidaceae)

Abstract Understanding how nutrient requirements of orchid mycorrhizal fungi (OMF) affect symbiotic germination is essential for the ex situ conservation threatened orchids and their symbioses. Yet influence isolate-level variation in OMF preferences on unknown. We tested Prasophyllum frenchii (Orchidaceae) 15 different media varying carbon macronutrient compositions with three Ceratobasidium isolates same operational taxonomic unit (OTU) as determined internal transcribed spacer locus sequencing. There was a significant interaction between fungal isolate percentage germination, each recording its highest (Isolate 9.3: 5.2 ± 1.4% MOM–S; Isolate 8.2: 5.4 1.1% MOM + S; 4.3: 2.2 0.5% 1.25 g/L wheat bran agar). Across all isolates, (percentage > 0) occurred more frequently agar (39.7% plates) than oatmeal (6.0% plates). also an effect type aerial hyphal growth behaviour isolate. All supported through to adult flowering plants. demonstrated that affected by composition. Further, differed significantly among OTU. This illustrates diversity functionally strains occurs within single OTU, previously unknown aspect research important ecological implications.