Analysis of the ectomycorrhizal community associated with Nothofagus pumilio seedlings in central Patagonia, Argentina

KUHAR F.; LÓPEZ BERNAL P.; RAJCHENBERG M.; BARROETAVEÑA C.

San Carlos de Bariloche

Congreso; II Simposio Internacional Simbiosis Micorrícica en Sudamérica; 2019

Lenga (Nothofagus pumilio) is present throughout the distribution of the Patagonian Andes forests, and has undergone significant degradation process mainly caused by forest fires, cattle grazing and logging, as it is one of the most valuable timber species. There is considerable evidence that the ectomycorrhizal (ECM) community associated with forest tree species changes during their development, but the mycobiota associated with Lenga in its early stages is largely unknown, although constitutes crucial information for nursery ECM inoculation management. The aims of this work were to study the ectomycorrhizal mycobiota associated to lenga seedlings, and to characterize their ECM community. The complete systems of 600 seedlings from three locations in Chubut province were analyzed for two consecutive years with spring and autumn samplings, selecting sapling patches with plants less than 30 cm height. Ectomycorrhizal morphotypes were characterized and molecularly identified by comparing the ITS sequences with a database produced in the framework of this study from sporomes collected in the plots and from other collections. It was found that the most frequent morphotypes correspond to Inocybe geophilomorpha (Inocybaceae), Descolea antarctica and Descolea brunnea (Bolbitiaceae), three species of the genus Cortinarius (Cortinariaceae), Tomentella tenuissima and Tomentella sp. (Thelephoraceae), and the ascomycetes Cenococcum geophilum (Gloniaceae) and Aleurina argentina (Pyronemataceae). The highest abundances correspond to I. geophilomorpha, C. geophilum, S. brunneus and two species of Cortinarius. No sporocarps of the species identified in the studied plots were found, suggesting that the abundance of ectomycorrhizal morphotypes would not be related to fructification frequency. Molecular data allowed identifying, in addition, the presence of species of the genera Tricholoma, Laccaria, Rickenella and Hysterangium. Differences in morphoytpes relative frequency were detected between sites but not between seasons and year. These data will allow to select appropriate mycobionts for nursery seedlings inoculations considering sites variations, in order to improve seedlings survival and growth in restoration actions.