RESUMO
Phylogenetic analyses have corroborated the discovery of three internal transcribed spacer (ITS) Types in Terfezia boudieri isolates in the course of earlier studies and have emphasized the divergence of Type 2 from Types 1 and 3. The application of molecular and physiological tools described below, revealed the existence of cryptic species within T. boudieri. The markers used include sequences taken from the 5' end of the ribosomal large subunit gene, a chitin synthase partial sequence, beta-tubulin partial sequence and amplified fragment length polymorphism (AFLP)-based markers. Following initial sequencing of a single PCR amplified sample for each Type, mass analysis of specimens relied on RFLP differences between the Types. Over 100 fruit bodies, 30 or more specimens for each ITS Type, were tested with each of the markers. The markers analysis divided the isolates into three groups, each correlated to a specific ITS Type. Two of the physiological traits examined: mycelial proliferation and mycorrhiza formation, consistently showed responses paralleling the ITS Types; the data presented suggest that T. boudieri is comprised of three cryptic species.
Assuntos
Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Quitina Sintase/genética , Impressões Digitais de DNA , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Proteínas Fúngicas , Genes de RNAr , Genótipo , Dados de Sequência Molecular , Micélio/crescimento & desenvolvimento , Técnicas de Tipagem Micológica , Micorrizas/crescimento & desenvolvimento , Filogenia , RNA Fúngico/genética , RNA Ribossômico/genética , Análise de Sequência de DNA , Tubulina (Proteína)/genéticaRESUMO
The ITS region including the 5.8S rRNA gene as well as the 5' end of the 28S rRNA gene of hypogeous Pezizaceae and Tuberaceae were studied to clarify the generic placement of two southern African desert truffles, Terfezia pfeilii and Choiromyces echinulatus. The results show that neither species belongs in the genus to which it has been assigned on the basis of morphological characters. As expected, two Choiromyces spp. grouped close to the representative of the Tuberaceae (Tuber melanosporum). However, C. echinulatus diverged from the other Choiromyces species and emerged near members of the genus Terfezia, being even closer to that genus than T. pfeilii. Two new genera and new species combinations, Kalaharituber gen. nov. with K. pfeilii (syn. T. pfeilii) comb. nov. and Eremiomyces gen. nov. with E. echinulatus (syn. C. echinulatus) comb. nov. are therefore introduced to accomodate these taxa. Both genera are closely related to Terfezia, and thus are placed in the Pezizaceae.