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Background Understanding the diversity and distribution of fungal communities at a regional scale is important since fungi play a crucial role in ecosystem functioning. Our study used environmental metagenomics to determine fungal communities in mountainous forest soils in the central highlands of Mexico. Methods We used four different bioinformatic workflows to profile fungal assemblages, i.e., Geneious+UNITE, single- and paired-end microbial community profiling (MiCoP), and Kraken2. Results The workflows yielded different results; one detected a higher abundance of ectomycorrhizal (EcM) and saprophytic fungi, while the other identified more saprophytic and pathogenic fungi. Environmental, vegetation, and geographical factors determined the spatial distribution of soil fungi at a regional scale. Potential hydrogen (pH), calcium (Ca), magnesium (Mg), and silt content were detected as common drivers of fungal communities across different datasets enriched towards a functional guild. Vegetation traits were found to be more influential in shaping symbiotrophic fungi composition than saprotrophic and pathogenic fungi. This highlights the importance of considering vegetation traits when studying fungal community diversity and distribution. Clustering patterns of sampling points near the volcanoes indicated shared environmental and vegetation characteristics. A weak but significant distance decay in taxonomic similarity revealed that dispersal limitation contributed to fungal community composition, although it was not the primary factor in this study. Overall, this study provides important insights into the challenges and opportunities of studying fungal communities at a regional scale using metagenomic data.

Aim of study: To assess the association of deforestation and forest use with tree diversity and dominance of pine species. Area of study: La Malinche National Park, central Mexico. Material and methods: Three forest stands were selected on each of four slopes in La Malinche National Park, in which the percent forest cover was determined using a concave spherical densitometer. Additionally, we estimated logging, firewood, and ocoteo as indirect measures of forest use. In each forest stand, we set five 0.1-ha circular plots and we recorded tree species, diameter at breast height, and height of all individuals ≥1.5 m. We estimated diversity using Hill numbers (qD). We identified dominant species from rank-abundance curves, and explored the dissimilarity between forest stands for the three q orders. Using generalized linear mixed-effects models, we evaluated the relationships of deforestation and forest use with species diversity and pine dominance, and studied the effect of pine dominance on the abundance of other tree species through generalized linear models. Main results: We recorded a total of 16 tree species; a pine (Pinus montezumae) was the dominant species. The diversity of tree species was not associated with forest use or deforestation, but deforestation increased Pinus dominance, with a strong slope effect. Research highlights: Regulation and control of forest use should be prioritized to avoid further deforestation and the transformation of species-diverse forests into monospecific forests, further increasing the dominance of P. montezumae. We also suggest reforesting with native species and those scarcely represented to increase forest cover and maintain tree diversity.

ABSTRACT The maternal transmission of microbiota during embryonic development of vertebrates is still poorly understood. Here, we used high-throughput sequencing of the 16S rRNA bacterial genes to determine the bacterial communities in the gastrointestinal tract and amniotic environment, i.e., the amniotic fluid, amniotic membrane and extraembryonic yolk, of embryos at the last stage of development of the viviparous lizard Sceloporus grammicus Wiegmann, 1828. We compared these communities to those found in the maternal intestine, mouth, cloaca, and the aseptic ventral skin as a control of the aseptic technique. Our results showed that bacterial 16S rRNA genes were present in the embryos of S. grammicus. Their diversity was lower and more similar in composition between individuals than those found in the maternal tissues. This suggests that a strong control exists on the transmission of bacteria from the mother to the embryos. We found 78% of the embryonic amplicon sequence variants (ASVs) in the maternal bacterial microbiota, suggesting that the transmission of bacteria from the mother to the embryos is a continuous process and some bacteria may have been transferred during early embryonic stages. The embryonic bacteria were found to overlap mostly with those found in the mouth and aseptic ventral skin of the mother, although it is difficult to conclude that the shared ASVs originated from these maternal tissues. Our study provides evidence of microbiota vertical transfer during embryonic development in the animal kingdom. It also highlights that this maternal transmission could be included in the maternal effects that impact the offspring. IMPORTANCE We investigated the presence and diversity of bacteria in the embryos of the viviparous lizard Sceloporus grammicus and their amniotic environment. We compared this diversity to that found in the maternal intestine, mouth, and cloaca. We detected bacterial DNA in the embryos, albeit with a lower bacterial species diversity than found in maternal tissues. Most of the bacterial species detected in the embryos were also found in the mother, although not all of them. Interestingly, we detected a high similarity in the composition of bacterial species among embryos from different mothers. These findings suggest that there may be a mechanism controlling the transmission of bacteria from the mother to the embryo. Our results highlight the possibility that the interaction between maternal bacteria and the embryo may affect the development of the lizards.

Abstract Background High-altitude ecosystems are extreme environments that generate specific physiological, morphological, and behavioral adaptations in ectotherms. The shifts in gut microbiota of the ectothermic hosts as an adaptation to environmental changes are still largely unknown. We investigated the food ingested and the bacterial, fungal, and protistan communities in feces of the lizard Sceloporus grammicus inhabiting an altitudinal range using metabarcoding approaches. Results The bacterial phyla Bacteroidetes and Firmicutes, and the genera Bacteroides and Parabacteroides dominated the core fecal bacteriome, while Zygomycota and Ascomycota, and the species Basidiobolus ranarum and Basidiobolus magnus dominated the core fecal mycobiome. The diet of S. grammicus included 29 invertebrate families belonging to Arachnida, Chilopoda, and Insecta. The diversity and abundance of its diet decreased sharply at high altitudes, while the abundance of plant material and Agaricomycetes was significantly higher at the highest site. The composition of the fecal microbiota of S. grammicus was different at the three altitudes, but not between females and males. Dietary restriction in S. grammicus at 4150 m might explain the high fecal abundance of Akkermansia and Oscillopira, bacteria characteristic of long fasting periods, while low temperature favored B. magnus. A high proportion of bacterial functions were digestive in S. grammicus at 2600 and 3100, while metabolism of aminoacids, vitamins, and key intermediates of metabolic pathways were higher at 4150 m. Different assemblages of fungal species in the lizard reflect differences in the environments at different elevations. Pathogens were more prevalent at high elevations than at the low ones. Conclusions Limiting food resources at high elevations might oblige S. grammicus to exploit other food resources and its intestinal microbiota have degradative and detoxifying capacities. Sceloporus grammicus might have acquired B. ranarum from the insects infected by the fungus, but its commensal relationship might be established by the quitinolytic capacities of B. ranarum. The mycobiome participate mainly in digestive and degradative functions while the bacteriome in digestive and metabolic functions.

Land-use change is one of the most important drivers of change in biodiversity. Deforestation for grazing or agriculture has transformed large areas of temperate forest in the central highlands of Mexico, but its impact on soil fungal communities is still largely unknown. In this study, we determined how deforestation of a high-altitude temperate forest for cultivation of maize (Zea mays L.) or husbandry altered the taxonomic, phylogenetic, functional, and beta diversity of soil fungal communities using a 18S rRNA metabarcoding analysis. The true taxonomic and phylogenetic diversity at order q = 1, i.e., considering frequent operational taxonomic units, decreased significantly in the arable, but not in the pasture soil. The beta diversity decreased in the order forest > pasture > arable soil. The ordination analysis showed a clear effect of intensity of land-use as the forest soil clustered closer to pasture than to the arable soil. The most abundant fungal phyla in the studied soils were Ascomycota, Basidiomycota, and Mucoromycota. Deforestation more than halved the relative abundance of Basidiomycota; mostly Agaricomycetes, such as Lactarius and Inocybe. The relative abundance of Glomeromycota decreased in the order pasture > forest > arable soil. Symbiotrophs, especially ectomycorrhizal fungi, were negatively affected by deforestation while pathotrophs, especially animal pathogens, were enriched in the pasture and arable soil. Ectomycorrhizal fungi were more abundant in the forest soil as they are usually associated with conifers. Arbuscular mycorrhizal fungi were more abundant in the pasture than in the arable soil as the higher plant diversity provided more suitable hosts. Changes in fungal communities resulting from land-use change can provide important information for soil management and the assessment of the environmental impact of deforestation and conversion of vulnerable ecosystems such as high-altitude temperate forests.

During field surveys of myxomycetes in Central America, 2 previously unrecorded genera and 4 species, viz. Craterium muscorum Ing, Dictydiaethalium dictyosporum Nann.-Bremek., Physarina echinocephala Höhn, and Stemonaria rufipes, were identified. Some of these are new for the Neotropics. These noteworthy range extensions of these species to the Mesoamerican biodiversity hotspot adds to our knowledge of rarely recorded myxomycetes worldwide. Images of the more relevant taxonomic characters are provided, and for some species, this is the first illustrations with macro and microphotographs and scanning electron microscopy images.

The results obtained from a second survey for Myxomycetes in the arid areas of Peru are reported. A total of 37 localities from the cactus belt (‘cardonal’), between 1500 and 3000 m a.s.l., were sampled over six years. This survey is based on 601 identifiable collections of myxomycetes, developed in the field under natural conditions or those that were recovered from moist chamber cultures. In total, 84 taxa representing 19 genera were recorded. One new species, Cribraria spinispora Lado & D.Wrigley sp. nov., is described, three species new to South America and 22 additional new species for Peru are reported as well. Endemic plants, expecially cacti, had a particular relevance as myxomycete substrates. The predominance of the order Physarales T.Macbr. in arid areas is reinforced. Comments are included on some collections, as well as SEM micrographs of several species. A statistical evaluation of the diversity of myxomycetes in the cardonal area and a comparison of this area with the dry coastal desert of Peru and other Neotropical xeric environments are also included. Results show that the arid areas are rich in myxomycetes, and that each area has a unique assemblage. The differences appear to be related to the host plants.

Background Terrestrial ecosystems play a significant role in carbon (C) storage. Human activities, such as urbanization, infrastructure, and land use change, can reduce significantly the C stored in the soil. The aim of this research was to measure the spatial variability of soil organic C (SOC) in the national park La Malinche (NPLM) in the central highlands of Mexico as an example of highland ecosystems and to determine the impact of land use change on the SOC stocks through deterministic and geostatistical geographic information system (GIS) based methods. Methods The soil was collected from different landscapes, that is, pine, fir, oak and mixed forests, natural grassland, moor and arable land, and organic C content determined. Different GIS-based deterministic (inverse distance weighting, local polynomial interpolation and radial basis function) and geostatistical interpolation techniques (ordinary kriging, cokriging and empirical Bayes kriging) were used to map the SOC stocks and other environmental variables of the top soil layer. Results All interpolation GIS-based methods described the spatial distribution of SOC of the NPLM satisfactorily. The total SOC stock of the NPLM was 2.45 Tg C with 85.3% in the forest (1.26 Tg C in the A horizon and 0.83 Tg C in the O horizon), 11.4% in the arable soil (0.23 Tg in the A horizon and only 0.05 Tg C in the O horizon) and 3.3% in the high moor (0.07 Tg C in the A horizon and

Los hongos micorrizógenos se encuentran en asociación con las raíces de muchas plantas, incluyendo casi todas las especies de árboles como la familia Pinaceae. Algunos derivados triterpénicos de lanosterol se han aislado tanto del micelio como de los cuerpos fructíferos del hongo ectomicorrizógeno Pisolithus arhizus. En el presente trabajo, se cultivó una cepa de la especie P. arhizus, aislada de bosques de pino en Oaxaca en condiciones de laboratorio, con el fin de determinar qué tipo de compuestos se pueden encontrar en una cepa mexicana cultivada bajo condiciones asimbióticas y sus posibles implicaciones ecológicas. Los resultados confirman que, en la fermentación líquida in vitro del micelio, la cepa aislada de los bosques de México presenta el mismo tipo de triterpenos sin funcionalidad con el carbono-23 como otras cepas procedentes de bosques de Europa y Brasil, a pesar de que se utilizó un medio de cultivo PDA en lugar del medio de cultivo Melin-Norkrans.

Results obtained from the first survey for myxomycetes in the hyperarid areas of Peru are reported. Sampling over three consecutive years was carried out at 96 localities between 0 and 1500 m elevation. A total of 78 species from 23 genera in all 6 myxomycete orders were determined from 723 collections of myxomycetes. One new species, Didymium peruvianum, is described, 2 species new to the Neotropics, 4 new records for South America and 41 additional new species for Peru are reported, increasing the country catalogue by over 50%. Results show that arid areas are rich in myxomycetes, and that each area has a unique species assemblage. Endemic plants had a particular relevance as myxomycete substrates. The predominance of the order Physarales in arid areas is reinforced, and the ecological importance of coastal fogs (garúas) is evident from the results. Comments are included on interesting or rare collections, as are SEM micrographs of several species and statistical evaluation of the results.

A new species of the myxomycete genus Perichaena is described in this paper. The new species, named Perichaena calongei, was found during intensive studies of arid areas of the Monte desert in Argentina. It has been found directly in the field from the provinces of Catamarca, La Rioja, Salta and San Juan, in the Northwest of Argentina, and isolated from moist chamber cultures of native plant species collected in Catamarca, Jujuy, Salta and San Juan. The characters that make this species unique in the genus are the combination of the morphology of the sporocarps, the structure and dehiscence of the peridium, and the ornamentation of the capillitium. The morphology of the my xo - mycete specimens was examined using light microscopy with Nomarski interference contrast, and scanning electron microscopy. Micrographs of relevant morphological characters are included. A key to facilitate the identification of the stipitate species of Perichaena is also proposed.

A new succulenticolous myxomycete of the genus Licea is described based on material from Spain (the Canary Islands), Mexico and the US A. It is very similar to L. biforis but differs in its smaller sporophores. and its bigger orange-yellow spores.The spores have a thick wall that is thinner and lighter towards one side. These differentiating characters were stable in spore to spore culture on agar.

Biodiversity surveys for myxomycetes (Amoebozoa) were carried out in three consecutive years (2009 to 2011) in the cold arid Patagonian Steppe, Argentina. The surveys, the first to cover such an extensive area in South America, form part of the Myxotropic project funded by the Spanish Government. Specimens were collected in 174 localities in four different provinces (Neuquén, Río Negro, Chubut and Santa Cruz), between 36° and 52° S latitudes. The most common types of substrate investigated were the dominant shrubs and grasses of the Patagonian steppe, and the Nothofagus forests, characteristic of the transition areas, but other plants such as small cacti and cushion plants were also included in the survey. A total of 133 different species and 5 varieties of myxomycetes representing 31 genera were identified in the 1134 specimens collected either in the field, or from moist chamber cultures prepared with samples of plant material obtained from the same collecting sites. The results include one species new to science, Perichaena nigra, and 17 species and two varieties that were previously unknown for either the Neotropics or South America, Badhamia armillata, Dianema mongolicum, Didymium annulisporum, D. leptotrychum, D. orthonemata, D. sturgisii, Echinostelium coelocephalum, Licea deplanata, L. nannengae, Macbrideola argentea, M. oblonga, Oligonema aurantium, Perichaena luteola, P. madagascariensis, Physarum luteolum, Protophysarum phloiogenum, Trichia contorta var. attenuata, T. contorta var. iowensis, T. erecta. An additional 19 species are new records for Argentina. These additions make Argentina the country in South America, at present, with the greatest number of myxomycetes catalogued having more than 50% of the species cited from the whole Neotropics. Diversity and biogeographic distribution of these organisms are discussed, and taxonomic comments on rare or unusual species are included and illustrated with photographs by LM and SEM. The results indicate that the myxomycetes, are widely distributed and are a normal component of Patagonian biota. Many of the substrates investigated were endemic plants from the region and are new substrates for a number of species of myxomycete. Differences between the variety of species in this area and others in Argentina and Chile, suggest a certain regional specialization of these organisms, the assemblage of which appear to depend on plant substrate species.