Leccinum(Boletaceae) in Costa Rica

Broadening the Knowledge of Mexican Boletes: Addition of a New Genus, Seven New Species, and Three New Combinations

Boletes are one of the most common groups of fungi in temperate, subtropical, and tropical ecosystems. In Mexico, the northern region has mainly been explored in terms of bolete diversity. This study describes a new genus and seven new species based on macromorphological, micromorphological, molecular, phylogenetic, and ecological data. Garcileccinum gen. nov. is typified with G. salmonicolor based on multigene phylogenetic analysis of nrLSU, RPB2, and TEF1, and it is closely related to Leccinum and Leccinellum. Garcileccinum viscosum and G. violaceotinctum are new combinations. Boletellus minimatenebris (ITS, nrLSU, and RPB2), Cacaoporus mexicanus (RPB2 and ATP6), Leccinum oaxacanum, Leccinum juarenzense (nrLSU, RPB2, and TEF1), Tylopilus pseudoleucomycelinus (nrLSU and RPB2), and Xerocomus hygrophanus (ITS, nrLSU, and RPB2) are described as new species. Boletus neoregius is reclassified as Pulchroboletus neoregius comb. nov. based on morphological and multigene phylogenetic analysis (ITS and nrLSU), and its geographic distribution is extended to Central Mexico, since the species was only known from Costa Rica. Furthermore, T. leucomycelinus is a new record from Mexico. This study contributes to increasing our knowledge of boletes and expands the diversity found in Mexican forests.

The Genus Leccinum (Boletaceae, Boletales) from China Based on Morphological and Molecular Data

Leccinum is one of the most important groups of boletes. Most species in this genus are ectomycorrhizal symbionts of various plants, and some of them are well-known edible mushrooms, making it an exceptionally important group ecologically and economically. The scientific problems related to this genus include that the identification of species in this genus from China need to be verified, especially those referring to European or North American species, and knowledge of the phylogeny and diversity of the species from China is limited. In this study, we conducted multi-locus (nrLSU, tef1-α, rpb2) and single-locus (ITS) phylogenetic investigations and morphological observisions of Leccinum from China, Europe and North America. Nine Leccinum species from China, including three new species, namely L. album, L.parascabrum and L.pseudoborneense, were revealed and described. Leccinum album is morphologically characterized by the white basidioma, the white hymenophore staining indistinct greenish blue when injured, and the white context not changing color in pileus but staining distinct greenish blue in the base of the stipe when injured. Leccinumparascabrum is characterized by the initially reddish brown to chestnut-brown and then pale brownish to brown pileus, the white to pallid and then light brown hymenophore lacking color change when injured, and the white context lacking color change in pileus but staining greenish blue in the base of the stipe when injured. Leccinumpseudoborneense is characterized by the pale brown to dark brown pileus, the initially white and then brown hymenophore lacking color change when injured, and the white context in pileus and stipe lacking color change in pileus but staining blue in stipe when bruised. Color photos of fresh basidiomata, line drawings of microscopic features and detailed descriptions of the new species are presented.

Morphological and molecular evidence supporting an arbutoid mycorrhizal relationship in the Costa Rican páramo

This study examines evidence for a particular arbutoid mycorrhizal interaction in páramo, a high-altitude neotropical ecosystem important in hydrological regulation but poorly known in terms of its fungal communities. Comarostaphylis arbutoides Lindley (Ericaceae) often forms dense thickets in Central American páramo habitats. Based on phylogenetic classification, it has been suggested that C. arbutoides forms arbutoid mycorrhizae with diverse Basidiomycetes and Ascomycetes; however, this assumption has not previously been confirmed. Based on field data, we hypothesized an arbutoid mycorrhizal association between C. arbutoides and the recently described bolete Leccinum monticola Halling & G.M. Mueller; in this study, we applied a rigorous approach using anatomical and molecular data to examine evidence for such an association. We examined root samples collected beneath L. monticola basidiomes for mycorrhizal structures, and we also compared rDNA internal transcribed spacer (ITS) sequences between mycorrhizal root tips and leaf or basidiome material of the suspected symbionts. Root cross sections showed a thin hyphal sheath and intracellular hyphal coils typical of arbutoid mycorrhizae. DNA sequence comparisons confirmed the identity of C. arbutoides and L. monticola as the mycorrhizal symbionts. In addition, this paper provides additional evidence for the widespread presence of minisatellite-like inserts in the ITS1 spacer in Leccinum species (including a characterization of the insert in L. monticola) and reports the use of an angiosperm-specific ITS primer pair useful for amplifying plant DNA from mycorrhizal roots without co-amplifying fungal DNA.