Predictors of Arbuscular Mycorrhizal Fungal Communities in the Brazilian Tropical Dry Forest.

Arbuscular mycorrhizal fungi (AMF) are symbiotic fungi with a broad distribution, and many taxa have physiological and ecological adaptations to specific environments, including semiarid ecosystems. Our aim was to address regional distribution patterns of AMF communities in such semiarid environments based on spore morphological techniques. We assessed AMF spores at the bottom and top of inselbergs distributed throughout the tropical dry forest in the Northeast region of Brazil. Across 10 replicate inselbergs and the surrounding area, spanning a range of altitude between 140 and 2000 m, we scored the AMF soil diversity and properties in 52 plots. We fitted parsimonious ordination analyses and variance partitioning models to determine the environmental factors which explained the variation in AMF community, based on morphological spore analysis. The diversity of AMF was similar at the bottom and top of inselbergs; however, we detected high variation in abundance and richness across sites. We formulated a parsimonious richness model that used physical soil factors as predictors. The AMF community structure could be best explained through the variables coarse and total sand, iron, organic matter, potassium, silt, and sodium which together accounted for 17.8% of total variance. Several AMF species were indicators of either deficiency or high values of specific soil properties. We demonstrated that habitat isolation of the inselbergs compared with surrounding areas did not trigger differences in AMF communities in semiarid regions of Brazil. At the regional scale, soil predictors across sites drove the distribution of symbiotic mycorrhizal fungi.

Resilience of Fungal Communities to Elevated CO2.

Soil filamentous fungi play a prominent role in regulating ecosystem functioning in terrestrial ecosystems. This necessitates understanding their responses to climate change drivers in order to predict how nutrient cycling and ecosystem services will be influenced in the future. Here, we provide a quantitative synthesis of ten studies on soil fungal community responses to elevated CO2. Many of these studies reported contradictory diversity responses. We identify the duration of the study as an influential parameter that determines the outcome of experimentation. Our analysis reconciles the existing globally distributed experiments on fungal community responses to elevated CO2 and provides a framework for comparing results of future CO2 enrichment studies.

Molecular epidemiology of senecavirus A associated with vesicular disease in pigs in Brazil.

Senecavirus A (SV-A) may cause vesicular disease and neonatal mortality in pigs, and was first detected in Brazil in 2015. Samples including tissues and serum from pigs with suspected vesicular diseases were collected from January to August in 2015 from farms in the states of Minas Gerais, Santa Catarina, Goiás and Rio Grande do Sul, Brazil, and tested for the presence of SV-A by reverse transcriptase PCR. All samples were negative for foot and mouth disease virus, as well as 13 other infectious agents associated with vesicular diseases in pigs. SV-A was detected by PCR in 65/265 (24.5%) specimens. A 530 base pair fragment sequenced from the VP1 protein coding region indicated a high genetic distance from SV-A in other countries, but a common origin among the Brazilian isolates.