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Acrostichum aureum is a halophytic pantropical invasive fern growing in mangroves and swamps. Its association with arbuscular mycorrhizal fungi (AMF) has been reported in Asia. AMF and their symbiosis (AM) commonly colonise the absorption organs of terrestrial plants worldwide. Furthermore, AMF/AM are well known for their capacity to bioaccumulate toxic elements and to alleviate biotic and abiotic stress (e.g., salinity stress) in their hosts. However, the mechanisms underlying AMF involvement in the halophytism of A. aureum and the structures where NaCl accumulates remain unknown. This study shows that A. aureum forms AM in margins of natural thermal ponds in Neotropical wetlands. All mature sporophytes were colonised by AMF, with high percentages for root length (ca. 57%), arbuscules (23), and hyphae (25) and low values for vesicles (2%). In A. aureum–AMF symbiosis, NaCl accumulated in AMF vesicles, and CaSO4 precipitated in colonised roots. Therefore, AM can contribute to the halophytic nature of this fern, allowing it to thrive in saline and thermal environments by capturing NaCl from fern tissues, compartmentalising it inside its vesicles, and precipitating CaSO4. [ABSTRACT FROM AUTHOR]

Background and aims: The plant's roots and fungi establish symbiotic endophytic associations that can coexist: arbuscular mycorrhizae and "dark septate" endophytes. Ferns and lycophytes are vascular plants that can form both fungal symbioses. The objective of this work is to detect the presence of fungal root endosymbiosis, know the mycorrhizal status, and analyze the type of colonizationin in native and ornamental ferns from the "Sierras Centrales de San Luis". M&M: In three sites in the "Sierras Centrales de San Luis", 9-10 individuals of each studied species were collected, their roots were processed to study these fungal. Characterization and quantification of their root colonization was evaluated. Results: In the three sites studied, Anemia tomentosa var. anthriscifolia formed mycorrhizal associations, the colonization presented abundant hyphal and arbusculated intracellular coils. In addition, glomoid spores of mycorrhizal fungi were found in their rhizospheres. Dark septate endophytes were absent in all species analyzed, none hyphae neither microsclerotia were recorded in roots of these native medicinal ferns. Conclusions: The mycorrhizal status of Anemia tomentosa var. anthriscifolia, one of the five medicinal fern species from the Sierras Centrales de San Luis studied, is presented. The arbuscular mycorrhizal colonization is described and quantified, and its type is determined as Paris. None of the fern species studied was associated with dark septate endophytes. [ABSTRACT FROM AUTHOR]

Geastrum minutisporum is characterized by a basidioma up to 25 mm wide, exoperidium saccate to planar, non-hygroscopic; a globose to subglobose, sessile and greyish brown endoperidium; a silky fibrillose peristoma, lighter or darker than the endoperidium and with globose, slightly asperulate basidiospores, 2–2.5–3 μm in diam, with a short apiculus up to 0.5 μm long. Specimens were collected at the Reserva Hídrica Provincial Pampa de Achala located in the upper portion of Sierras Grandes from Córdoba, central Argentina. Morphology and phylogenetic analysis based on sequences of the ribosomal DNA internal transcribed spacer region support Geastrum minutisporum as a new species. [ABSTRACT FROM AUTHOR]

Low arbuscular-mycorrhizal (AM) sporulation in arid field soils limits our knowledge of indigenous species when diversity studies are based only on spore morphology. Our aim was to use different approaches (i.e., spore morphological approach and PCR–SSCP (single-strand-conformation-polymorphism) analysis after trap plant multiplication strategies to improve the knowledge of the current richness of glomalean AM fungi (Glomerales; Glomeromycota) from the Argentine Puna. Indigenous propagules from two pristine sites at 3870 and 3370 m of elevation were multiplied using different host plants; propagation periods (2–6 months), and subculture cycles (1; 2; or 3) from 5 to 13 months. The propagule multiplication experiment allowed the detection of different glomoid taxa of Funneliformis spp. and Rhizoglomus spp., which were considered cryptic species since they had never been found in Puna soils before. On the other hand; almost all the generalist species previously described were recovered from cultures; except for Glomus ambisporum. Both plant host selection and culture times are critical for Glomerales multiplication. The SSCP analysis complemented the morphological approach and showed a high variability of Glomus at each site; revealing the presence of Funneliformis mosseae. This study demonstrates that AMF trap culture (TC) is a useful strategy for improving the analysis of AM fungal diversity/richness in the Argentinean highlands. [ABSTRACT FROM AUTHOR]