BackgroundGenomic DNA extracted from species of Cactaceae is often contaminated with significant amounts of mucilage and pectin. Pectin is one of the main components of cellular walls, whereas mucilage is a complex polysaccharide with a ramified structure. Thus, pectin- and mucilage-free extraction of DNA is a key step for further downstream PCR-based analyses.ResultsWe tested our DNA extraction method on cladode tissue (juvenile, adult, and herbaria exemplars) of 17 species of Opuntia Mill., which are characterized by a large quantity of pectin and mucilage.ConclusionWe developed a method for the extraction of gDNA free of inhibitory compounds common in species of Opuntia Mill., such as pectin and mucilage. Compared to previously extraction protocols, our method produced higher yields of high-quality genomic DNA.

Matsutake fungi include a complex of edible mushrooms highly prized worldwide, particularly in Japan where they are considered one of the most luxurious ingredients. These species establish ectomycorrhizal symbioses with angiosperms and gymnosperms in the Northern Hemisphere and in North America only three species are currently known. In the present contribution a fourth species of this geographical area is described, Tricholoma colposii sp. nov. is described from Veracruz state, in eastern Mexico based on morphological and molecular (nrITS) data. This species is characterized by middle size basidiomata, with orange brown to brown pileus and stipe, squamose when young and with appressed scales in maturity, cylindric, fibrillous to scaly stipe, with globose to ellipsoid (4.5–)5–6 (–7) × (3–) 4–5 (–6) μm smooth spores, sporomes with sweet fruit odor and raw green bean flavour. The species grows associated with Pinus teocote forests. The macro- and micromorphological characters in conjunction with the nrITS-based phylogenetic analysis using Maximum Likelihood method and Bayesian inference support the proposal of this new species of Mexican matsutake. Detailed descriptions, photographs and comparisons with phenetic and phylogenetic related species are presented.

<p class="p1"><span class="s1">Se describe una nueva especie silvestre de <em>Opuntia </em>(L.)Mill. (Cactaceae) de frutos comestibles ácidos (xoconostles), conocida localmente como “xoconostle matizado”, basados en micromorfología (areola, espina, glóquida, polen y semilla) y morfología externa. Se compara morfológicamente con otras tres especies silvestres distribuidas en la misma región: <em>O. joconostle</em>, <em>O. oligacantha </em>y <em>O. matudae</em>. Con base en el análisis filogenético de un gene de cloroplasto, un espaciador intergénico de cloroplasto y un marcador nuclear se reconoce a la especie como un grupo monofilético dentro del grupo de <em>Opuntia sensu stricto</em>.</span></p>

In this study, we update the systematics of the Tabernaemontana and describe the general patterns of species diversity and conservation status in Mexico. A total of 18 species were registered, including one cultivated species, two new species described here (T. chamelensis L.O. Alvarado & Lozada-Pérez and T. ochoterenae L.O. Alvarado & S. Islas), and eight species endemic to Mexico, which in total represents 47% of the diversity of the genus in the country. The states of Chiapas, Oaxaca, and Veracruz had the highest species diversity in native and endemic species. A map based on the kriging approach and the sums of species distribution models corroborate the sites of high diversity. A comparison among American countries showed that Central American countries share more specific similarity than South American ones. A risk evaluation showed that six species are under threat, mainly the endemic species. This exercise demonstrated that this genus is an interesting model to understand the biogeography, evolution, and affinities of the tropical flora of the Americas. Our work provides a basis for a deeper study of the biogeography and biology of the members of genus Tabernaemontana.

A detailed morphological and molecular study on Opuntia matudae and O. hyptiacantha is presented. These two species have been long considered to belong to the same taxon, although no investigations were carried out in depth. Moreover, no published phylogenetic study of the genus Opuntia include both species. Our data support the recognition of O. matudae and O. hyptiacantha as different and unrelated species.