RESUMO
Mycena subpiligera, a new taxon in sect. Fragilipedes that can strongly enhance the germination efficiency of Gastrodia elata seeds, was discovered in subtropical areas of China. As revealed by a morphological comparison with related Mycena species as well as maximum likelihood (ML) and Bayesian phylogenetic analyses based on sequences of the internal transcribed spacer (ITS) and the large subunit (LSU) regions of nuclear ribosomal RNA, the new taxon can be distinguished from phenotypically similar and phylogenetically related species. Optimal cultural conditions for M. subpiligera basidiomata are reported, and the germination rate of the new species is compared with that of M. citrinomarginata.
RESUMO
Phylogenetic relationships between Tuber pseudoexcavatum and other Tuber species were investigated by studying the sequences of four genes: 5.8S-ITS2, beta-tubulin, protein kinase C and elongation factor 1alpha. The four phylogenetic trees allowed to differentiate the black truffle clade, composed of two subclades, one comprising the Asian black truffles (T. indicum, T. sinense, T. himalayense) and the Perigord black truffle (T. melanosporum), the second comprising T. pseudoexcavatum and T. brumale. These two subclades diverged relatively early. We propose a common ancestor, located between Europe and China, to all the black truffles. The T. brumale/pseudoexcavatum subclade would have started to diverge and migrate first, T. brumale towards Europe through a northern route and T. pseudoexcavatum towards China. Later the T. melanosporum subclade would have started to migrate through the same route, T. melanosporum towards Europe and T. indicum towards China, leading to vicariant species.
Assuntos
Ascomicetos/classificação , Ascomicetos/genética , Genes Fúngicos , Ascomicetos/ultraestrutura , Sequência de Bases , China , Primers do DNA/genética , DNA Fúngico/genética , DNA Intergênico/genética , Europa (Continente) , Proteínas Fúngicas/genética , Microscopia Eletrônica de Varredura , Fator 1 de Elongação de Peptídeos/genética , Filogenia , Proteína Quinase C/genética , Alinhamento de Sequência , Especificidade da Espécie , Esporos Fúngicos/ultraestrutura , Tubulina (Proteína)/genéticaRESUMO
When examined using SEM, Chinese samples of Tuber indicum and T. sinense displayed the same ascospore ornamentation as that of T. pseudohimalayense, T. indicum, collected in India by Duthie in 1899, and samples renamed T. himalayense in 1988. The different authors who named the four taxa (T. indicum, T. himalayense, T. sinense, T. pseudohimalyense) described differences in the surface of the peridium which could be considered as usual variations within a single species. We consider T. indicum, T. himalayense, T. sinense and T. pseudohimalayense as one species, T. indicum. Within this T. indicum complex, according to ITS and beta-tubulin sequences, there are two groups in China, which could be considered as geographical ecotypes. This study is the first to identify a genetic and phylogeographical structure within the Chinese Tuber species.