RESUMO
Background: The Brazilian Atlantic Forest is one of the most biodiverse terrestrial ecoregions of the world. Among its constituents, restinga vegetation makes a particular case, acting as a buffer zone between the oceans and the forest. Covering some 80% of Brazilian coastline (over 7,300 km in length), restinga is a harsh environment where plants and fungi interact in complex ways that just now are beginning to be unveiled. Ectomycorrhizal symbiosis, in particular, plays a so far ungauged and likely underestimated role. We recently described the morpho-anatomical and molecular features of the ectomycorrhizae formed by several basidiomycetous mycobionts on the host plant Guapira opposita, but the mycorrhizal biology of restinga is still largely unexplored. Here, we report new data on the ectomycorrhizal fungal symbionts of G. opposita, based on the collection of sporomata and ectomycorrhizal root tips in restinga stands occurring in southern Brazil. Methods: To obtain a broader view of restinga mycorrhizal and ecological potential, we compiled a comprehensive and up-to-date checklist of fungal species reported or supposed to establish ectomycorrhizae on restinga-inhabiting host plants, mainly on the basis of field observations. Results: Our list comprises some 726 records, 74 of which correspond to putative ectomycorrhizal taxa specifically associated with restinga. These include several members of Boletaceae, Amanita, Tomentella/ Thelephora, Russula/ Lactifluus, and Clavulina, as well as hypogeous fungi, like the recently described Longistriata flava. Conclusions: Our survey reveals a significant diversity of the restinga ectomycorrhizal mycobiota, indicating the importance of this symbiosis for the ecological functioning of a unique yet poorly known and threatened ecosystem.
Assuntos
Micorrizas , Ecossistema , Simbiose , Florestas , Biodiversidade , PlantasRESUMO
In this work, we characterize naturally occurring mycorrhizae formed by Amanita viscidolutea on Guapira opposita in the Atlantic Forest in Brazil. We sequenced the rDNA ITS region from the mycorrhizae and basidiomata to identify both symbionts. Amanita viscidolutea mycorrhizae were up to 43 mm long, mostly simple, and unbranched to irregularly pinnate. The fungal mantle surface was velvety to slightly cottony and white to yellowish with silver patches. Hyphal strands were infrequently present. Although the fungal mantle consisted of clampless hyphae, emanating hyphae and hyphal strands had sparsely distributed clamp connections. A unique character of the mycorrhizae was the absence of a Hartig net.
RESUMO
Guatemala is one of the richest biodiversity hotspots worldwide, bursting a wild array of ecosystems that range from pine and mixed forests in the highlands to tropical rain forests in the extensive El Petén area, bordering Belize and Mexico. Despite this biological wealth, however, current knowledge on the Guatemalan mycobiota is particularly scant, in part because of the prolonged civil war that has prevented exploration of many ecological niches. In the present paper, we report on the occurrence of Lactarius rimosellus Peck-a rarely discussed species-in oak-pine mixed forests in the Guatemalan highlands and describe the relevant ectomycorrhizae formed with Quercus sp. by means of molecular and morpho-anatomical tools. On the phylogenetic trees constructed on the basis of the partial LSU sequence, sporocarp- and ectomycorrhizae-derived sequences formed a common, statistically supported clade. The structural features of the ectomycorrhizae of L. rimosellus were generally found to match those described on various hosts for other Lactarius species belonging to the subgenus Russularia, where L. rimosellus has been traditionally assigned. These mycorrhizae are characterized by a pseudoparenchymatous outer mantle layer, with epidermoid or angular hyphal cells, and a plectenchymatous inner mantle layer; lactifers are embedded either in the middle and/or inner mantle layer. In the framework of a more general, ongoing study of the ethnomycology of the Maya populations in the Guatemalan highlands, we also report on the traditional knowledge about Lactarius mushrooms and their uses among native people.