Taxonomic revision of Physalis in Mexico

Physalis (Solanaceae, Solanoideae) is an American genus of ca. 90 species, with its diversity centered on Mexico. We recognize 61 species within the country, for which we provide a generic morphological description, an artificial key to determine species, and brief descriptions. We include distributions, habitats, diagnostic characters, phenology, and uses. Distribution maps and field photographs are also provided. We include conservation status as evaluated by the IUCN

Modelado de los factores ambientales que determinan la distribución de especies sinantrópicas de physalis

Modelado de la distribución de especies sinantrópicas de Physalis. Lugares con distribución potencial y real de especies de Physalis (tomatillos)El modelado de la distribución de especies sinantrópicas (malezas) y los factores ambientales que determinan dicha distribución han sido poco estudiados. Physalis tiene 90 especies distribuidas en las Américas, y algunas especies en el Viejo Mundo. México alberga cerca de 70 especies y aproximadamente 35 son endémicas. La sección Angulatae incluye diez especies, todas sinantrópicas en mayor o menor grado. Las especies se concentran en la Sierra Madre Occidental, la Sierra Madre del Sur y en la Faja Volcánica Transmexicana. El objetivo de este trabajo fue modelar e identifi car las variables ambientales que determinan la distribución potencial de las diez especies de Physalis sección Angulatae. Se emplearon 524 registros revisados por especialistas en la taxonomía del grupo y 20 variables ambientales; de éstas 12 fueron climáticas, tres edáfi cas, dos de cobertura de la vegetación y tres de atributos topográfi cos. Los modelos se calcularon con el algoritmo Maxent. Los resultados del modelado mostraron que el hábitat más adecuado para la persistencia de ocho especies se defi nió por el índice normalizado diferencial de vegetación en los meses secos del año, la materia orgánica del suelo, la altitud y el aspecto, las cuales en conjunto explicaron entre el 73 y el 91 % de la variación en su distribución. Otros factores como la precipitación total anual y la isotermalidad determinaron la distribución de P. crassifolia y de P. glabra, respectivamente. El índice normalizado diferencial de la vegetación y las propiedades de los suelos, son predictores determinantes en la distribución potencial de las especies de la sección Angulatae. Palabras clave: máxima entropía, predictores ambientales, sección Angulatae, tomatillos. Abstract: The modeling of the distribution of synanthropic (weedy) species and the environmental factors that determine their distribution is not well studied. Physalis has 90 species distributed in the Americas, and several in the Old World. Mexico harbors about 70 species and approximately 35 are endemic. The section Angulatae includes 10 species, all synanthropic to some degree. The species tended to concentrate in the Sierra Madre Occidental, the Sierra Madre del Sur, and the Transmexican Volcanic Belt. The aim of this work was to model and identify the environmental variables that determine the potential distribution of the ten species of Physalis sect. Angulatae. A total of 524 records that had been verifi ed by the taxonomic experts of the group and 20 environmental variables were used; 12 were climatic, and the other eight were novel and of different types: three soil properties, two normalized differential vegetation indexes and three topographic attributes. The models were obtained with the Maxent algorithm. The results of the modelling showed that the most suitable habitat for the persistence of eight species was delimited by the normalized differential vegetation index during the dry months of the year, the soil organic matter, the elevation and the aspect, which together explained between the 73 and 91 % of the variation in its distribution. Other groups of factors like total precipitation and isthermality determined the distribution of P. crassifolia and P. glabra, respectively. We show that the novel environmental factors such as the normalized differential vegetation index and the soil properties were decisive predictors in the potential distribution of the species in the section Angulatae.Conacy

Characterization of the plastome of Physalis cordata and comparative analysis of eight species of Physalis sensu stricto

In this study, we sequenced, assembled, and annotated the plastome of Physalis cordata Mill. and compared it with seven species of the genus Physalis sensu stricto. Sequencing, annotating, and comparing plastomes allow us to understand the evolutionary mechanisms associated with physiological functions, select possible molecular markers, and identify the types of selection that have acted in different regions of the genome. The plastome of P. cordata is 157,000 bp long and presents the typical quadripartite structure with a large single-copy (LSC) region of 87,267 bp and a small single-copy (SSC) region of 18,501 bp, which are separated by two inverted repeat (IRs) regions of 25,616 bp each. These values are similar to those found in the other species, except for P. angulata L. and P. pruinosa L., which presented an expansion of the LSC region and a contraction of the IR regions. The plastome in all Physalis species studied shows variation in the boundary of the regions with three distinct types, the percentage of the sequence identity between coding and non-coding regions, and the number of repetitive regions and microsatellites. Four genes and 10 intergenic regions show promise as molecular markers and eight genes were under positive selection. The maximum likelihood analysis showed that the plastome is a good source of information for phylogenetic inference in the genus, given the high support values and absence of polytomies. In the Physalis plastomes analyzed here, the differences found, the positive selection of genes, and the phylogenetic relationships do not show trends that correspond to the biological or ecological characteristics of the species studied

Análisis multiescala de las comunidades de coral hermatípico del Pacífico Central Mexicano

The Mexican Central Pacific is located in a zone of oceanographic transition between two biogeographic provinces with particular conditions that affect the associated fauna. The objective of this study was to evaluate the variation of hermatypic coral assemblages in this region and to determine their relationship with the heterogeneity of the benthonic habitat and spatial variables. A total of 156 transects were carried out at 41 sites in the years 2010 and 2011. The sampling effort returned 96.7% of the coral richness expected for the area, with a total of 15 species recorded. The results showed that richness, diversity and cover of corals varied only at the site and state scales. However, the composition and coverage of all coral species, as well as the benthonic habitat structure, differed significantly across the study scales (i.e. sites, zones and states). Canonical redundancy analysis showed that variation in the richness, diversity and assemblages of corals was explained by the cover of live corals, articulated calcareous algae, sandy substrate, sponges and fleshy macroalgae. This study suggests that local scale (i.e. site) variation in the coral assemblages of the Mexican Central Pacific is the result of the heterogeneity of the benthonic habitat, while geomorphological and oceanographic characteristics play a greater role at regional scale.El Pacífico Central Mexicano se localiza en una zona de transición oceanográfica entre dos provincias biogeográficas con condiciones ambientales particulares que afectan la fauna asociada. El objetivo del estudio fue evaluar la variación de las comunidades de coral hermatípico de esta región y determinar su relación con la heterogeneidad del hábitat bentónico y variables espaciales. Se realizaron 156 transectos en 41 sitios en los años 2010 y 2011. El esfuerzo de muestreo representó el 96.7% de la riqueza de coral esperada para el área, con un total de 15 especies registradas. Los resultados mostraron que la riqueza, diversidad y cobertura de corales variaron sólo en las escalas de sitio y de estado. En cambio, la composición y cobertura de todas las especies de coral, así como la estructura del hábitat bentónico, fueron significativamente diferentes en todas las escalas estudiadas (i.e. sitio, zona y estado). Los análisis de redundancia canónica mostraron que la variación de la riqueza, diversidad y de las comunidades de corales eran explicadas por la cobertura de coral vivo, algas calcáreas articuladas, sustrato arenoso, esponjas y macroalgas carnosas. Este trabajo sugiere que la variación de las comunidades de coral en el Pacífico Central Mexicano a escala local (i.e. sitio) se debe a la heterogeneidad del hábitat bentónico, mientras que a escala regional, las características geomorfológicas y oceanográficas desempeñan un papel más importante

Ensamblajes bacterianos asociados a especies de coral del Pacífico central mexicano

The functional role of coral-associated bacteria and their contribution to coral health is still largely unknown. The first necessary step to address this gap in the knowledge is based on characterization of the microbial assemblage of the coral and the species-specific, temporal and spatial variation in its diversity. Branched corals (e.g., genus Pocillopora), are the main builders of coral reefs worldwide. This study evaluated the bacteria associated with the mucus and tissues of Pocillopora damicornis and Pocillopora verrucosa, as well as that of the seawater and surrounding sediments, in 6 sites of the Mexican Central Pacific during summer and winter seasons. The molecular techniques DGGE and RFLP were used with the 16S rDNA to assess the most abundant bacterial OTUs. The relationships between the bacterial-coral assemblage and environmental and spatial variables of the reef surroundings were also evaluated, using the multivariate analyses. Twenty different Operational Taxonomic Units (OTU) were obtained, with the highest number presented by the sediments. Specificity of bacterial groups was found for each coral species, as well as between the tissue and mucus of each species. The results showed that the bacterial dominant groups were similar between seasons, but these showed significant spatial variations among substrates within sites, as well as per substrate across all sites. The environmental variables that explained the variation of the dominant bacterial groups in corals and sea water were the coverages of fleshy macroalgae, live coral and sponge. In contrast, variation in the sediments was explained by the coverages of sand, rubble and rock.El papel funcional de las bacterias asociadas a corales y su contribución a la salud del coral es aún desconocido en gran medida. Es necesario que primero se caracterice el ensamblaje microbiano del coral y sus cambios en la diversidad a través de las especies de coral, el espacio y tiempo. Los corales ramificados (e.g., género Pocillopora) son los principales constructores arrecifales a nivel mundial. Este estudio evaluó la estructura bacteriana asociada al mucus y tejidos de Pocillopora damicornis y Pocillopora verrucosa, así como del agua de mar y sedimentos circundantes en 6 sitios del Pacífico central mexicano. Se emplearon las técnicas DGGE y RFLP del ADNr 16S para generar los perfiles de bandeo o evaluar la diversidad. Además, se evaluó la relación del ensamblaje bacteriano-coral con variables ambientales y espaciales del entorno arrecifal (de cada sitio), utilizando análisis multivariados. Se obtuvieron 20 Unidades Taxonómicas Operacionales (OTU) diferentes, siendo los sedimentos los que presentaron mayor número. Se encontró una especificidad de grupos bacterianos para cada especie de coral, así como entre el tejido y mucus de cada especie. Los resultados mostraron que los grupos de bacterias dominantes variaron entre sustratos y entre sitios, encontrando, sólo una variación espacial significativa. Las variables ambientales que explican la variación de los grupos bacterianos dominantes en corales y agua de mar fueron las coberturas de macroalgas carnosas, coral vivo y esponja. En cambio, la variación en los sedimentos fue explicada por las coberturas de arena, escombro y roc

Extinction risk of Mesoamerican crop wild relatives

Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge. Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity. We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material. There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations