Morphometric and molecular variation in concert: taxonomy and genetics of the reticulate Pyrenean and Iberian alpine spiny fescues (Festuca eskia complex,Poaceae)

The Iberian mountain spiny fescues are a reticulate group of five diploid grass taxa consisting of three parental species and two putative hybrids: F. × souliei (F. eskia × F. quadriflora) and F. × picoeuropeana (F. eskia × F. gautieri). Phenotypic and molecular studies were conducted with the aim of determining the taxonomic boundaries and genetic relationships of the five taxa and disentangling the origins of the two hybrids. Statistical analyses of 31 selected phenotypic traits were conducted on individuals from 159 populations and on nine type specimens. Molecular analyses of random amplified polymorphic DNA (RAPD) markers were performed on 29 populations. The phenotypic analyses detected significant differences between the five taxa and demonstrated the overall intermediacy of the F. × picoeuropeana and F. × souliei between their respective parents. The RAPD analysis corroborated the genetic differentiation of F. eskia, F. gautieri and F. quadriflora and the intermediate nature of the two hybrids; however, they also detected genetic variation within F. × picoeuropeana. These results suggest distinct origins for F. × picoeuropeana in the Cantabrian and Pyrenean mountains, with the sporadic Pyrenean populations having potentially resulted from recent hybridizations and the stabilized Cantabrian ones from older events followed by potential displacements of the parents. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 676–706.     

Assessment of the Relationship between Self-Declared Ethnicity,Mitochondrial Haplogroups and Genomic Ancestry in Brazilian Individuals

In populations that have a high degree of admixture, such as in Brazil, the sole use of ethnicity self-declaration information is not a good method for classifying individuals regarding their ethnicity. Here, we evaluate the relationship of self-declared ethnicities with genomic ancestry and mitochondrial haplogroups in 492 individuals from southeastern Brazil. Mitochondrial haplogroups were obtained by analyzing the hypervariable regions of the mitochondrial DNA (mtDNA), and the genomic ancestry was obtained using 48 autosomal insertion-deletion ancestry informative markers (AIM). Of the 492 individuals, 74.6% self-declared as White, 13.8% as Brown and 10.4% as Black. Classification of the mtDNA haplogroups showed that 46.3% had African mtDNA, and the genomic ancestry analysis showed that the main contribution was European (57.4%). When we looked at the distribution of mtDNA and genomic ancestry according to the self-declared ethnicities from 367 individuals who self-declared as White, 37.6% showed African mtDNA, and they had a high contribution of European genomic ancestry (63.3%) but also a significant contribution of African ancestry (22.2%). Of the 68 individuals who self-declared as Brown, 25% showed Amerindian mtDNA and similar contribution of European and African genomic ancestries. Of the 51 subjects who self-declared as black, 80.4% had African mtDNA, and the main contribution of genomic ancestry was African (55.6%), but they also had a significant proportion of European ancestry (32.1%). The Brazilian population had a uniform degree of Amerindian genomic ancestry, and it was only with the use of genetic markers (autosomal or mitochondrial) that we were able to capture Amerindian ancestry information. Additionally, it was possible to observe a high degree of heterogeneity in the ancestry for both types of genetic markers, which shows the high genetic admixture that is present in the Brazilian population. We suggest that in epidemiological studies, the use of these methods could provide complementary information.     

Protozoa Drive the Dynamics of Culturable Biocontrol Bacterial Communities

Some soil bacteria protect plants against soil-borne diseases by producing toxic secondary metabolites. Such beneficial biocontrol bacteria can be used in agricultural systems as alternative to agrochemicals. The broad spectrum toxins responsible for plant protection also inhibit predation by protozoa and nematodes, the main consumers of bacteria in soil. Therefore, predation pressure may favour biocontrol bacteria and contribute to plant health. We analyzed the effect of Acanthamoeba castellanii on semi-natural soil bacterial communities in a microcosm experiment. We determined the frequency of culturable bacteria carrying genes responsible for the production of the antifungal compounds 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin (PRN) and hydrogen cyanide (HCN) in presence and absence of A. castellanii. We then measured if amoebae affected soil suppressiveness in a bioassay with sugar beet seedlings confronted to the fungal pathogen Rhizoctonia solani. Amoebae increased the frequency of both DAPG and HCN positive bacteria in later plant growth phases (2 and 3 weeks), as well as the average number of biocontrol genes per bacterium. The abundance of DAPG positive bacteria correlated with disease suppression, suggesting that their promotion by amoebae may enhance soil health. However, the net effect of amoebae on soil suppressiveness was neutral to slightly negative, possibly because amoebae slow down the establishment of biocontrol bacteria on the recently emerged seedlings used in the assay. The results indicate that microfaunal predators foster biocontrol bacterial communities. Understanding interactions between biocontrol bacteria and their predators may thus help developing environmentally friendly management practices of agricultural systems.     

Thermal niche for seed germination of Xyris species from Brazilian montane vegetation: Implications for climate change

Understanding how climate change will affect regeneration from seeds is important for developing conservation strategies. We evaluated seed germination requirements for sympatric species of Xyris from montane rupestrian grasslands (campo rupestre) in Brazil to determine their thermal niche and thermal requirements for seed germination. We also assessed whether projected temperature increases would affect seed germination of the species. Seed germination was evaluated at a wide range of constant temperatures (10–40°C) under light (12-hr photoperiod) and dark conditions. Base temperatures (T_b) and thermal times for 50% germination (θ₅₀) were calculated for three species. The effects of projected mean temperature increase on seed germination percentage and timing were evaluated. All species revealed an absolute light requirement for germination. Thermal germination niche breadth was greatest for X. asperula (15 to 35°C) and narrowest for X. seubertii (20 and 25°C). Base temperatures for X. asperula, X. pilosa and X. trachyphylla were 9.0, 12.8 and 11.1°C, respectively. In the scenario with the highest temperature increase (A2), the greatest reductions in seed germination are observed for X. pilosa and X. seubertii. The lowest projected temperature increase (2°C) was sufficient to decrease by 1 day the germination time of X. asperula and X. pilosa. Species of Xyris do not present a pattern for thermal germination niche and thermal requirements values, indicating that the effects of climate warming on the regeneration of these seeds will probably vary among species.     

Detection of Mycobacterium leprae DNA in clinical and environmental samples using serological analysis and PCR

Molecular Biology Reports - Leprosy is a chronic infectious disease caused by Mycobacterium leprae and persists as a serious public health problem in Brazil. This microorganism is inculturable,...     

Host plant distributions and climate interact to affect the predicted geographic distribution of a Neotropical termite

Species distribution models (SDMs) have been widely used in the scientific literature. The majority of SDMs use climate data or other abiotic variables to forecast the potential distribution of a species in geographic space. Biotic interactions can affect the predicted spatial distribution of a species in many ways across multiple spatial scales, and incorporating these predictors in an SDM is a current topic in the scientific literature. Constrictotermes cyphergaster is a widely distributed termite in the Neotropics. This termite species nests in plants and more frequently nests in some arboreal species. Thus, this species is an excellent model to evaluate the influence of biotic interactions in SDMs. We evaluate the influences of climate and the geographic distribution of host plants on the potential distribution of C. cyphergaster. Three correlative models (MaxEnt) were built to predict the geographic distribution of the termite: (1) climate data, (2) biotic data (i.e., the geographic distribution of host plants), and (3) climate and biotic data. The models that were generated indicate that the potential geographic distribution of C. cyphergaster is concentrated in the Cerrado and Caatinga regions. In addition, path analysis and multiple regression revealed the importance of the direct effects of biological interactions in the geographic distribution of the termite, while climate affected the distribution of the termite mainly through indirect effects by influencing the geographic distributions of host plants. The current study endorses the importance of including biological interactions in SDMs. We recommend using biotic predictors in SDM studies of insect species, mainly because insects have important environmental services and biotic interaction data can improve the macroecological studies of this group.     

Use of agroecosystem matrix habitats by mammalian carnivores (Carnivora): a global‐scale analysis

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A journey through the Amazon Middle Earth reveals Aspidoras azaghal (Siluriformes: Callichthyidae), a new species of armoured catfish from the rio Xingu basin,Brazil

Aspidoras azaghal n. sp. was discovered during a multitaxonomic scientific expedition to the remote Amazon Terra do Meio region in tributaries to the rio Xingu basin, Pará, Brazil. The new species can be promptly distinguished from its congeners by the following combination of features: (a) absence of the first dorsal-fin element; (b) parieto-supraoccipital fontanel located medially on bone; (c) absence of a longitudinal dark-brown or black stripe along flank midline; (d) ventral surface of trunk covered by clearly smaller, irregular and/or roundish platelets; (e) inner laminar expansion of infraorbital 1 well developed; (f) relatively wide frontal bone, with width equal to half of entire length; (g) absence of a thick, longitudinal conspicuous dark-brown stripe along dorsal portion of flank; and (h) poorly developed serrations on posterior margin of the pectoral-fin spine. Besides morphological evidence, the molecular analyses indicated significant differences between the new species and its congeners, with A. albater and A. raimundi as its closest species, showing 6.53% of genetic differentiation in both cases. The intraspecific molecular data revealed gene flow (peer fixation index, FST = 0.05249, P > 0.05, for the cytochrome oxidase I (COI) marker and FST = -0.01466, P > 0.05, for the control region) between specimens upstream and downstream from a 30-m height waterfall at the type-locality, which therefore represent a single population. Furthermore, it was possible to observe a unidirectional gene flow pattern, with genetic diversity increasing in the downstream direction.