Factors affecting the establishment of selected edible ectomycorrhizal fungi of Pinus in South-Western Australia

W.A. Dunstan

Establishment of a new industry in plantations of Pinus spp. in south-western Australia, based on edible ectomycorrhizal fungi, will be dependant on the ability of new fungal introductions to survive and proliferate under limitations imposed by biotic and abiotic factors. This thesis investigated factors that would influence establishment of two most valuable fungi, Matsutake (Tricholoma matsutake) and the Pine Mushroom {T. magnivelare). Factors that were investigated included, extant ectomycorrhizal fungi, plant host - fungus compatibility, climate and soils. A survey of ectomycorrhizal (ECM) fimgi associated with introduced Pinus spp. in south-western Australia increased the number of identified species to 15-16 species, from seven previously reported in the literature. Most species form a sub-set of species that have also been introduced to Eastern Australia, and are early colonizers of pines, forming ECM associations with pine seedlings, but are also found with plantationgrown pine trees older than sixty years. Four species of basidiomycetes with resupinate fruitbodies, are new records for Australia, and probably for the Southern Flemisphere. One resupinate fungus (Amphinema byssoides) has been introduced. In contrast, three Tomentella spp., that are part of a suite of at least 25 tomentelloid fungi found in native forests and woodlands in south-western Australia, appear to have made a transition from native to introduced Pinus hosts. Species within other genera of resupinate fungi, that are known to form ECM associations with pines in the Northern Hemisphere, were also identified but not confirmed as ECM fungi of pines in Western Australia. rDNA sequence data strongly suggested that some previous records of ECM fungi have been mis-identified. In two field experiments, Thelephoraceae {Thelephora terrestris and Tomentella stuposa) formed 50-60% of ectomycorrhizas but sporocarps of both Ilmgi were found infrequently or not at all in surveys. The apparent below-ground dominance by representatives of the Thelephoraceae, as ECM fungi of pines in south-western Australia, is similar to some results from natural conifer forests in Europe and North America. Sporocarp production, by naturally occurring pine ECM fungi, was measured over a season in experimental plots of five year-old P. radiata trees, that comprised trees planted with a standard treatment and trees planted for agro-forestry, with additional P fertilization and a cover crop of the legume Trifolium subterraneum. Sporocarp production in agro-forestry plots was estimated to be at least ca. 73 kg'1 ha'1 yr'1 d.w., that was significantly greater than that of the standard treatment, and up to an order of magnitude greater than productivity in natural conifer forests. There were also changes in phenology of sporocarp production by different species of fungi between treatments. Comparison of climate between selected locations within the ranges of T. matsutake and T. magnivelare, and locations within south-western Australia strongly suggests that T. magnivelare, and T. nauseosum, syn. T. matsutake from the Western Mediterranean, are more suited to the climate of south-western Australia than Asian T. matsutake. Soils within south-western Australia that are potentially suitable for Matsutake, that are derived from similar parent materials and with similar physical and chemical properties, occupy an undefined proportion of about 3250 km'2 of soil sub-systems within the area that may be climatically suitable. In vitro synthesis experiments between isolates of Tricholoma matsutake and T.magnivelare and host plants, Pinus dens [flora, P. radiata and P. pinaster, showed that internal structures comparable with natural Pinus densiflora-T. matsutake ECM were formed between P. radiata and T. matsutake. Macro- and micro-morphological features of infected short roots suggested that P. radiata and P. pinaster are suitable hosts for both T. matsutake and T. magnivelare. In contrast to in vitro synthesis experiments, ECM associations failed to form between T. matsutake and mature P. radiata trees after inoculation with two forms of vegetative mycelium, and ECM also failed to form between T. matsutake and Pinus spp. inoculated with two forms of vegetative mycelium under more controlled conditions in a glasshouse experiment.

Factors affecting the establishment of selected edible ectomycorrhizal fungi of Pinus in South-Western Australia

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