RESUMO
Tricholoma matsutake, known widely as "matsutake," has great commercial and cultural significance in Japan. Because Japanese production is insufficient to meet the high domestic demand, morphologically similar mushrooms, thought by many to belong to T. magnivelare, are imported from western North America. However, molecular data produced since the early 2000s have indicated that more than one species of matsutake occur in North America and this raises the question of correct naming for the different species. To address this question, we assessed the phylogenetic diversity within North American matsutake based on nuc rDNA ITS1-5.8S-ITS2 (internal transcribed spacer [ITS] barcode) sequences, including newly obtained sequences from the type collections for Agaricus ponderosus and Armillaria arenicola, and morphological characters. Our results agree with earlier indications that three matsutake species occur in North America and allow us to clarify the correct application of names-T. magnivelare from the eastern USA and Canada, T. murrillianum from the western USA and Canada, and T. mesoamericanum from Mexico, newly described here. The existence of the three North American species is further supported by the results of evolutionary divergence analysis, geographical distributions, and morphological characters.
Assuntos
Variação Genética , Terminologia como Assunto , Tricholoma/classificação , Tricholoma/genética , Agaricus/classificação , Agaricus/genética , Agaricus/isolamento & purificação , Armillaria/classificação , Armillaria/genética , Armillaria/isolamento & purificação , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , América do Norte , Filogenia , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA , Tricholoma/citologia , Tricholoma/isolamento & purificaçãoRESUMO
⢠To further assess the usefulness of stable isotope ratios for understanding elemental cycling and fungal ecology, we measured δ15 N and δ13 C in ectomycorrhizal and saprotrophic macrofungi, plants, woody debris and soils from two old-growth conifer forests in Olympic National Park, Washington, USA. ⢠Ecosystem isotope patterns were similar at the two forests, but differences existed that appear to reflect soil nitrogen availability and C allocation within the ectomycorrhizal symbioses. δ15 N and δ13 C of ectomycorrhizal and saprotrophic fungi differed in both forests, and a dual δ15 N/δ13 C plot provided the best means of distinguishing them. Within both groups, δ15 N and δ13 C differed among genera and species, and the difference in species composition was an important determinant of the different overall δ15 N of the ectomycorrhizal fungi at the two forests. ⢠Variation in multiple ecophysiological traits such as organic N use, mycelial morphology and transfer of N to phytobionts appears to underlie the variation in the isotope signatures of ectomycorrhizal fungi. ⢠The varied isotope signatures of ectomycorrhizal fungi suggest considerable functional diversity among them. Life-history strategies could provide a framework for interpreting these patterns.
RESUMO
⢠Over 400 species of achlorophyllous vascular plants are thought to obtain all C from symbiotic fungi. Consequently, they are termed 'myco-heterotrophic.' However, direct evidence of myco-heterotrophy in these plants is limited. ⢠During an investigation of the patterns of N and C stable isotopes of various ecosystem pools in two old-growth conifer forests, we sampled six species of myco-heterotrophic achlorophyllous plants to determine the ability of stable isotope ratios to provide evidence of myco-heterotrophy and host-specificity within these symbioses. ⢠Dual-isotope signatures of the myco-heterotrophic plants differed from those of all other pools. They were most similar to the signatures of ectomycorrhizal fungi, and least like those of green plants. δ15 N values of the myco-heterotrophic plants correlated strongly and positively with those of putative mycobionts. ⢠Used in conjunction with other techniques, N and C stable isotope ratios can be used to demonstrate myco-heterotrophy and host-specificity in these plants when other ecosystem pools are well characterized. They also appear promising for estimating the degree of heterotrophy in photosynthetic, partially myco-heterotrophic plants.
