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La situación actual nos confronta con un problema de salud de proporciones globales, entender las implicaciones generales de una pandemia viral nos permitirá un mejor entendimiento de los procesos que las generan. En este trabajo se muestran aspectos históricos sobre el surgimiento de tres zoonosis virales pandémicas, además de los métodos estandarizados de diagnóstico y aspectos económicos y sociales relevantes para entender la repercusión que este tipo de padecimientos tienen sobre la humanidad. Si actualmente solo se conoce un 0.1 % de la diversidad de virus que afectan a los mamíferos, existe una alta probabilidad que la próxima pandemia se encuentre entre esos virus desconocidos.

Los coronavirus son capaces de infectar riñones, hígado, sistema nervioso central, gastrointestinal y respiratorio; tanto en humanos como en animales; por lo que son patógenos de interés clínico, veterinario y económico. Estos virus tienden a mutar de manera efectiva y frecuente, lo que les confiere la capacidad de transitar entre diferentes especies y los vuelve muy contagiosos y peligrosos. Dentro de las enfermedades causadas por coronavirus y que representan una amenaza para la salud pública se encuentra el SARS (síndrome respiratorio agudo severo), el MERS (síndrome respiratorio de Oriente Medio) y el SARS-CoV-2 (COVID-19), así como otras enfermedades del ganado, aves, gatos, perros y muchos otros animales salvajes que representan un reservorio probable de transición para humanos y animales domésticos. Sin embargo, existen muy pocos virus descritos para la familia y se calcula que hay más de 32,000 variedades no descubiertas aún, específicas de mamíferos, por lo que hay un alto potencial de infecciones. Este ensayo presenta la información actualizada y sintetizada sobre la historia, clasificación y taxonomía de los coronavirus, la relación entre la biología del virus con la infección, las mutaciones y las aplicaciones biotecnológicas para el desarrollo de vacunas.

The use of allometric tools allows estimating the biomass of a plant species with greater precision. Tree roots are the least studied part of the vegetation due to the difficulty in obtaining complete root systems. For this reason, the objective was to generate an allometric model to estimate the amount of biomass accumulated in the root system of Abies religiosa trees in El Chico National Park, Hidalgo. For this purpose, 61 trees of A. religiosa were extracted from 0.06 to 3.56 m in height, using a backpack sprayer of pressurized water that detached the soil from the root. The response variable was root fresh weight and the independent variables were height, diameter and age+1, according to the fit of the models tested. Diameter was the variable with the best fit (r2 = 0.95 ± 0.04), obtaining the following equation PFR = (20.918 + D (2.4475)). The allometric model accurately estimates the below-ground biomass contained in the roots, which will allow us to obtain the complete biomass of an A. religiosa forest by having access to data on both the aerial and root components.

La cantidad de contaminantes a los que nos enfrentamos crece rápidamente, tanto en cantidad como en variedad. Dentro de este material externo, los metales pesados destacan por su capacidad de interactuar con moléculas biológicas, pero ¿qué hacen exactamente una vez que entran en el cuerpo? Aun cuando son necesarios en pequeñas cantidades para varios procesos fisiológicos, tienden a acumularse en el cuerpo más rápido de lo que pueden ser metabolizados. La principal vía de entrada de los metales pesados es a través de la dieta, presentando mayor disponibilidad al ser solubilizados en agua o al ingerir alimentos marinos, ya que existe un fenómeno denominado bioacumulación. Entre los metales más comunes en cuerpos de agua se encuentran el arsénico, cadmio, cromo, mercurio y plomo, cada uno genera diferentes padecimientos al inducir alteraciones bioquímicas y fisiológicas en los organismos. Por lo anterior, el objetivo de este trabajo es documentar las alteraciones provocadas por la exposición a metales pesados a través de las cadenas tróficas, comenzando por la contaminación en cuerpos de agua y finalizando en la alimentación humana.

Demography is a key area for obtaining information for monitoring and conserving threatened plants. Abies hidalgensis is a microendemic species of Hidalgo state, listed as threatened in the category VuD2 in the IUCN Red List but not mentioned in the Mexican regulation NOM-059-SEMARNAT due to low existing information. The aim of this research was to evaluate the effect of forest extraction on demographic aspects of Abies hidalgensis. Individuals over 1.5 m tall and with diameters at chest height over 2.5 cm were censused in nine populations with different management conditions. Seedlings were counted in 0.1 ha circles, and their age was registered. Taller individuals were grouped with a cluster analysis and contrasted between extraction treatments by a generalized discriminant function analysis. These groups were used to build static life tables showing fecundity by stage, and the individual numbers from each treatment and population were resampled with a Markovian 10,000-step bootstrap procedure to calculate a stochastic population growth rate. The seedling data was also contrasted by a generalized discriminant function analysis. An age estimation model was fitted to determine age based on diameters. Forest exploitation causes loss of the biggest trees, leading to a notable change of the population structure with an increase of seedlings, loss of fecundity, dominance of small plants, average age decrease, and a decrease in the stochastic population growth rate. However, even when the nine populations are growing, management activities generate a greater risk of mortality in the initial stages and loss of fertile adults.

We attempted to identify the factors influencing size and shape dimorphism between sexes, as well as among populations and species in the Sceloporus scalaris group (Sceloporus aeneus, S. scalaris, S. bicanthalis and S. subniger). Our analysis focused on five morphological characteristics: snout–vent length, head length, head width, forearm length and tibia length. The effect of environmental variables (precipitation and temperature) on these variables was also tested. We found differences in morphological traits between sexes, and among populations of the same species. The oviparous species (S. aeneus and S. scalaris) were larger in overall body size than the viviparous species (S. bicanthalis and S. subniger). Differences in overall body size among populations were recorded only in S. aeneus and S. scalaris. Male-biased sexual size dimorphism occurred in oviparous but not viviparous lizards (except for one population of S. bicanthalis). An absence of sexual size dimorphism was also recorded in S. subniger and some populations of the remaining species. Two different shape patterns were found; the first was female-biased with larger relative body length in almost all populations, which could be explained by fecundity, and the second was male-biased with relatively larger head and limbs in a few populations, which may be explained by sexual selection. The patterns of sexual size and shape dimorphism show that environment, rather than phylogeny, may be determining the extent of sexual dimorphism. These types of studies show the importance of an integrated evaluation of interpopulation and interspecies variation to determine the factors that generate sexual dimorphism.

Antecedentes: Con base en caracteres morfológicos de hojas, flores y frutos se han segregado nuevas especies del complejo Magnolia mexicana en México. Por su importancia evolutiva, ecológica y de uso medicinal es relevante analizar la variación morfológica y conocer el estado actual de sus poblaciones en su área de distribución. Preguntas: ¿Existe diferenciación en la morfología de hojas, flores y frutos en las poblaciones de M . mexicana ? ¿Cuál es el estado actual de las poblaciones de M . mexicana ? Especie de estudio: Magnolia mexicana (DC.) G. Don (Magnoliaceae). Sitios y años de estudio: El estudio se realizó en seis poblaciones de M. mexicana en la Sierra Madre Oriental, entre mayo y octubre de 2019 y 2020. Métodos: Se analizaron 480 hojas, 240 flores y 84 frutos mediante análisis univariados y multivariados. Resultados: Los primeros componentes principales explicaron 85, 69 y 68 % de la variación foliar, floral y frutal, respectivamente; y las primeras 2 funciones discriminantes 82, 66 y 94 % de dicha variación. Los caracteres morfológicos con mayor variación fueron: diámetro del peciolo y vena media, número de estambres, ancho de carpelos, y largo y ancho de semillas. Conclusiones: El rango de variación en las características morfológicas de M . mexicana fue más amplio que el documentado en la descripción original de la especie. Las poblaciones están aisladas y presentan baja densidad y alta diferenciación morfológica entre sí, en particular en flores y frutos, por lo que su identidad taxonómica requiere ser corroborada a nivel genético.

Horizontal gene transfer (HGT) is one of the most interesting evolutionary events in Eukaryotic life. It has been proven that fungi share genes or gene clusters with other organisms such as plants, animals, or other fungi. The amatoxins biosynthesis metabolic pathway produces lethal bicyclic peptides responsible for most of the deaths by mushroom poisoning. It is assumed that involved genes passed from Galerina and Lepiota to the Amanita secc. Phalloidae species by HGT. We used de novo genome assembling and gene mining for homologous amanitin genes among Agaricomycetes lineages. Phylogenetic and reconciliation trees were constructed to address the evolutionary history of POP gene family responsible for amanitin maturation. We also looked for the potential cytotoxicity of sequenced samples on plant bioassays. New and known edible species in Amanita rubescens complex have, partially or completely, the gene’s package implied in the synthesis of amatoxins, making them potentially capable of synthesizing these lethal metabolites. The evolutionary history of these genes is more complex than previously reported involving at least ten HGT events, four duplication events, other fungal genera such as Piloderma and Russula, and several edible mushrooms. Furthermore, we showed that samples from a traditionally consumed species within Amanita rubescens complex had the same cytotoxicity capabilities as the lethal amanitas from the Phalloideae section. In conclusion, several old duplications and horizontal gene transfer events originated a cryptic diversity of the POP gene family in toxic and edible fungi raising questions on the safe consumption of species in the A. rubescens complex.

En el artículo previo, en este mismo número de la revista Herreriana, se analizó el problema de la conservación biológica en México, tomando como referencia algunos grupos de organismos. En este escrito, como complemento y continuación, se abordan los temas de la legislación existente, así como información de las diferentes dependencias que trabajan en la conservación biológica en México, se mencionan las posibles causas que impiden que los programas de manejo y conservación en nuestro país sean efectivos y se proponen algunas estrategias y acciones que involucran la concientización y participación de todos los sectores de la sociedad, para lograr que la conservación biológica en el país sea tangible.

En este trabajo se exponen diferentes puntos de vista sobre la problemática actual de la conservación de la biodiversidad en México, tomando como referencia algunos grupos de animales y plantas (insectos, anfibios, reptiles, aves y plantas). El objetivo es dar a conocer los problemas que enfrentan estos organismos ante los cambios recientes provocados por las actividades humanas y discutir si existen estrategias adecuadas y tangibles de manejo y conservación de los mismos en el país.

Antecedentes: Las flores son elementos reproductivos costosos que presentan balances costo/beneficio en sus estructuras. La diversidad de éstas se ha atribuido a factores bióticos como las interacciones con sus visitadores florales y abióticos como las características del ambiente. Preguntas: ¿La morfología floral de M. geometrizans está relacionada con los tipos de vegetación? ¿La comunidad de artrópodos visitadores florales se relaciona con la morfología floral y/o el tipo de vegetación? ¿La morfología floral y la comunidad de artrópodos tendrán relación con la perturbación del ambiente? Especie de estudio: Myrtillocactus geometrizans (Mart. ex Pfeiff.) Console Sitio de estudio y fecha: Selva Baja Caducifolia y Matorral Xerófilo en las Reservas de la Biosfera Tehuacán-Cuicatlán, Puebla Barranca de Metztitlán, Hidalgo. México. Marzo 2017. Métodos: En los cuatro sitios (dos días por sitio), durante el pico de floración de M. geometrizans, se calculó el índice de disturbio, se recolectaron 30 flores (N = 120) y los artrópodos visitadores florales. Se determinaron la morfología floral y los artrópodos. Resultados: Los sitios de la Barranca de Metztitlán presentaron el mayor índice de disturbio, las flores más chicas y mayor número de estructuras florales. Los visitadores florales fueron más abundantes en los matorrales xerófilos, particularmente en el sitio más perturbado donde el grupo funcional más relevante fue el de los polinizadores. Conclusiones: Se encontraron diferencias significativas en la morfología floral de M. geometrizans relacionadas a los tipos de vegetación y ubicación geográfica. Se reportó una compensación entre tamaño y producción de estructuras florales.

The Chelonian lineage has been exposed to several climate change events along its evolutionary history, but the rapid contemporary change in climate patterns has the potential to erode turtle populations. This study focuses on (1) evaluating the climatically suitable area available for 15 species of mud turtles of the genus Kinosternon, and on (2) assessing whether or not these species retain their ancestral climate niche. Occurrence data was collected for these species and, using the Maxent algorithm and WorldClim bioclimatic variables, suitable present and future climatic niche areas were modeled. In addition, we also carried out climatic niche similarity analyses between pairs of species to evaluate whether these conserve their climatic niche. Our models suggest that most species of Kinosternon will lose a high proportion of their suitable habitat in the future. Most mud turtle species seem to conserve their climatic niche, suggesting the prevalence of niche conservatism in the group. Our results indicate that several mud turtle species could be at severe risk of disappearing over the next few decades due to the loss of climatically suitable areas and of the conservation of their climatic niches.

The species of the genus Tetranychus Dufour are highly specialized pests that produce significant economic losses in crops. The red spider mite, Tetranychus merganser Boudreaux (Acari: Tetranychida...

Determining the effects of disturbance on genetic variation of plant populations is an important step in establishing conservation strategies for the survival of natural populations. Distur...

En la actualidad, las plantas medicinales contienen principios activos, que si bien son los responsables de las propiedades terapéuticas que se les atribuyen, también lo son de las intoxicaciones y reacciones adversas que pueden aparecer si se emplean en dosis inadecuadas o por períodos prolongados. Por lo tanto, el objetivo del presente trabajo es evaluar la posible capacidad antimutágena del extracto etanólico de té verde (Camellia sinensis) sustentado en su alto contenido antioxidante reportado. Para ello, se determinó la actividad antimutagénica mediante la prueba de mutación y recombinación somática (SMART), con un tratamiento previo de extractos etanólicos de té verde y tratamiento subsecuente con un mutágeno de referencia (O-Toluidina), evaluando la inhibición de manchas o clones celulares en ojo de Drosophila melanogaster. En cuanto a los resultados, se observó que el extracto etanólico administrado previamente al mutágeno de referencia, inhibió de manera significativa el daño genotóxico, siendo más efectivo para manchas pequeñas que grandes. En general, los resultados sugirieron que los extractos de té verde evaluados, tienen propiedades biológicas con un potencial benéfico para la salud humana y que se pueden utilizar en tratamientos preventivos contra el cáncer o exposición relacionadas con mutágenos de manera laboral o naturales.

Species modify their morphological attributes in response to environmental variation as an adaptive strategy, a situation aggravated by current conditions of rapid alteration of global ecosystems. ...

Wild mushrooms are important to the nutritional health and economic subsistence of rural populations in Mexico, but inaccurate identification of mushrooms has led to reported cases of poisoning. The aim of this study is to establish genotoxic profiles of mushrooms of the putative Amanita rubescens complex and to link those profiles with morphological attributes that suggest a correct identification of mushrooms, in order to prevent poisoning. Several combinations of amplification products (AMA, PHA, POP1, and POP2 genes) were identified in A. rubescens fungi sold in traditional markets; these genes are related to the presence of toxic polypeptides and its enzymatic regulators. The sequences correspond to a previously reported toxic gene family (MSDIM). All samples with the complete toxic gene profile presented reddish to dark-brown sporomes; this is the only attribute that visually distinguishes samples with toxic potential. Our results suggest that the mushrooms sold in traditional Mexican markets do not correspond to the A. rubescens complex. We conclude that morphological variability allows for identification of edible and inedible mushrooms.

Background: The agaves are plants of cultural importance that have been used by humans for about 10,000 years for about 40 specific uses, of which the most culturally and economically important are fermented (Pulque) and distilled beverages (Mescal). Pulque continues to be produced in nearly all of Mexico, and the agaves used for this propose have shown domestication syndrome and selected morphological characteristics, such as larger plant size (since size is positively related to sap production) and less dentition of the leaves.Methods: In this study, we carry out an ethnobotanical, morphological and genetic analysis of the traditional varieties of pulque agave used in the production of aguamiel (agave sap) and pulque in two localities of the state of Hidalgo. We did semi-structured interviews and tours with crop owners, tlachiqueros (sap harvesters), and people related to the production system. We analyzed the morphology of 111 plants, and we studied the diversity and genetic structure of 130 individuals using 16 nuclear microsatellites.Results: We found wild, tolerated, transplanted, and cultivated varieties of agave. Asexual reproduction was the main method of propagation. We recorded 19 traditional varieties of pulque agave, 12 of them in production during the study, which correspond to the species Agave americana, A. salmiana y A. mapisaga with five intraspecific entities. The varieties were grouped according to a management gradient; the wild varieties were the smallest, with more lateral teeth and a larger terminal spine. The cultivated varieties clearly exhibited domestication syndrome, with larger plants and smaller dentition. The expected heterozygosity (He) of the varieties ranged between 0.204 to 0.721. Bayesian clustering suggested the existence of three genetic groups (K = 3), both at the level of traditional varieties of pulque agaves and for management categories, a result that matches multivariate clustering.Conclusions: Pulque producers in the studied localities, maintain high agrobiodiversity. The cultivated varieties exhibit domestication syndrome, as has been reported for other species of the genus with the same selection purposes. Our results support the hypothesis of a decrease in genetic diversity in crops compared to wild agaves, which seems to be due to vegetative propagation, among other factors.

Los recursos fitogenéticos están representados por toda la variedad y combinaciones posibles de rasgos que permiten a las especies vegetales adaptarse a los cambios en el medio; a mayor cantidad de rasgos y combinaciones, mayor es la probabilidad de que una especie pueda subsistir. El estado de Hidalgo presenta condiciones topográficas que lo hacen mega-diverso, ya que crean un mosaico de paisajes que someten a las plantas a diferentes presiones de selección. Sin embargo, de toda esa diversidad muy poca ha sido evaluada a nivel genético, por lo que en este trabajo se presentará un resumen de tres estudios específicos que se han realizado en la región hidalguense. En general, el uso inadecuado de los recursos (Cedrela odorata), el aislamiento (Fagus grandifolia subsp. mexicana) y la perturbación (Ceratozamia fuscoviridis) son los principales problemas a los que se enfrentan los recursos fitogenéticos del Estado de Hidalgo.

Background and Aims: Cedrela odorata (Spanish cedar) is a tropical tree native to America with an important international trade market. In this study, the morphological variation of C. odorata was compared among three conditions: logging, plantations, and natural populations, with the objective to evaluate the current condition of managed populations after harvesting and in plantations, in contrast to relatively well-preserved populations. Methods: Two sites were chosen for each condition. The population density and four morphological attributes were measured: diameter at breast height, height, angle of branch insertion and crown form. A multivariate approach was used to compare the morphological variation among conditions (generalized discriminant factors analysis) and determine total variation distributed among size classes (cluster analysis), as well as assignment of these classes to each condition (canonical correspondence analysis). Key results: Four significantly different size classes were identified among all populations with specific association to condition. Strongest correlations were between highest trees with natural populations and small trees with plantations. Forest management, including harvesting and plantation conditions, reduced the phenotypical variation and modified the dasometrical attributes of C. odorata. The logging of the better shaped phenotypes increased the smaller size trees frequency compared to commercial size individuals, and changed the forest composition favoring small categories. Conclusions: The forest exploitation generates homogenization in median height-class and the plantation in lower height-class. In both cases, the harvestable trees are scarce, even after 20 years of management; and they are non-existent in plantations of 15 years. These results suggest that the removal of the highest trees, as well as forest plantations, are not being effective to wood production since they do not reach commercial sizes in the time of recovery or projected growth.

Tecoma stans es una planta utilizada en México y América Central para el tratamiento tradicional de la diabetes con un éxito variable dependiendo del origen, el entorno y otras fuentes de variación subyacentes. Para determinar la variación morfológica y genética asociada con una mejor inhibición de la α –glucosidasa, se probaron extractos etanólicos de siete poblaciones, tres silvestres y cuatro cultivos. La variación morfológica y genética se encuentran correlacionadas y ambas difieren significativamente entre poblaciones. La población de El Arenal obtuvo el máximo de actividad inhibitoria y presentó un genotipo particular compartido con dos cultivos que tuvieron una actividad similar, aunque no existen rasgos morfológicos asociados con el potencial antidiabético. Nuestros resultados sugieren un componente genético de la actividad terapéutica asociada con una fuente particular, pero una plasticidad morfológica independiente que podría no ser un indicador de la mejor respuesta terapéutica.

Background and Research Aims Dicksonia navarrensis is a species of tree fern at risk of extinction, distributed in the montane cloud forest (MCF) of the Americas from the central region of Mexico to Ecuador. In Mexico, populations of this species grow in primary vegetation of the MCF, in a matrix with a high degree of fragmentation and under threat of disappearance. Methods In the present study, the diversity and genetic structure of seven populations of D. navarrensis that are distributed in the cloud forest of the Sierra Madre Oriental were evaluated, with both standard laboratory and statistical analysis techniques, using 11 microsatellites developed for the genus Dicksonia. Results A total of 33 alleles were found. Genetic diversity differed between populations, and some presented low heterozygosity. Using assignment tests, three genetic groups were identified, associated with the geographical distribution of the populations; those from the north maintain connectivity with each other but diverge highly from the populations in the south, probably due to processes of isolation by distance (local environment), genetic drift, and natural selection. Conclusion The northernmost population, which is more isolated from the rest, has a broader genetic reservoir, which can be useful for maintaining the genetic diversity of the species. In the other populations, with less genetic diversity, the introduction of individuals and/or the dispersion of spores is important, to maintain and increase the genetic variability that they still possess, but which could disappear in a short time if their habitat continues to deteriorate at a high degree. Implications for Conservation The results obtained provide basic information that can be used in management and conservation plans, because the populations with the greatest genetic diversity and the possible processes that are influencing the genetic structure of the species were identified.

Ceratozamia zaragozae has been considered to be the most threatened cycad species in its genus since only 50 individuals were reported for the only known population in the state of San Luis Potosi, Mexico. In this report we present information on newly discovered populations, as well as data on their population structure and spatial distribution. Six different populations were found, one of which is located in a Natural Protected Area. Population density was low (0.05 ± 0.038 ind/m2) and populations exhibited an unconventional ecological affinity for the genus, occurring on igneous soils in oak and pine-oak forests at elevations over 2000 m. Populations showed heterogeneous growth rates (λ = 0.89 ± 0.49). Spatial clustering patterns in all populations indicated adequate recruitment, low survival of juveniles, and spatial dependence between seedlings/juveniles and reproductive adults. We recommend the ex-situ cultivation of the species and the establishment of corridors between areas of habitat, in order to secure the preservation of the species.

Zamia inermis, a narrowly endemic cycad, has been classified under the International Union for Conservation of Nature Red List as critically endangered on the basis of a 75% population decline over past 50 yr. There is only one known population occupying an area of less than 10 km2, with 654 individuals with extremely low seed production and recruitment. This study compares the genetic diversity of the only known in situ population of Z. inermis and one ex situ population established 5 yr ago by a local community running a rural backyard nursery. We aimed to assess the current conservation status and to propose a more efficient management strategy. Our results by using a total of 10 simple sequence repeat loci showed a low observed heterozygosity (0.151 ± 0.075) in comparison to other New World cycads. Significant differences were found between ex situ population and wild populations (differentiation index FST1, 156 = 0.734, P < 0.001), with lower variation within (27%) than among (73%) populations. Zamia...

Demographic studies of endemic and threatened plant species are essential for establishing effective conservation strategies. This paper aims to determine the structure and dynamics of the only natural population reported for Zamia inermis. All individuals were mapped to determine the spatial structure and patterns of association between categories and sexes. Matrix analysis were conducted to determine the population dynamics based on three on-site visits. The population is distributed randomly, although seedlings were found to be aggregated at all scales, juveniles are aggregated in smaller radii up to 4.5 m and males at radii above 3.5 m. Seedlings and juveniles are associated with males over greater radii of 3 m, the dependence of adults from earlier categories and females is less than 1.5 m. The population growth rate confirms that the population is in decline (λ = 0.963 ± 0.011). Although few juveniles were identified and no seedling survival was observed in the field, also the amount of viable seeds per female cone is low. However, inhabitants of the region are cultivating the species by germinating seeds in backyard nurseries with 92 of 954 seeds reaching the juvenile category to date. It is clear that the population has lost its regenerative potential and is simply holding on to persistence of adults, this implies a great risk to the species. Ex situ propagation is encouraged.

Fifty-five adult Dicrocoelium rileyiMacy, 1931 parasitizing Tadarida brasiliensis (Geoffroy, 1824) from Durango, Nuevo Leon, Puebla, Zacatecas and Mexico State were morphologically described and morphometrically analyzed. To evaluate the degree of variation among populations from the five localities, 27 morphometric measures of this species were transformed into an orthogonal factor by principal component analysis (PCA), and a posterior comparison among populations was performed using discriminant analysis of principal components (DAPC). Significant differences were observed with exceptions between the Puebla – Zacatecas and Nuevo Leon – Mexico State populations when forming three groups with an 88 % assignation. The Durango population was the most dissimilar population. These results show that the morphological traits of D. rileyi are variable among the populations in this study due to local intraspecific variation; however, some of the specimens present in the distinct localities may represent different species. Molecular analysis is necessary to accurately define whether the populations involved in our study constitute one or several species.

Fine-scale spatial genetic structure (SGS) analysis has proved to be a useful tool to establish the distribution of genetic variability between individuals and how these patterns are affected by microenvironmental conditions, associations with pollinators and dispersers, and sex ratio. In this study, the correlation between the fine-scale SGS of a population of Zamia furfuracea L. fil. and its dependence on the patterns of spatial aggregation between categories of life cycle and the proportion of males and females was determined by using intersimple sequence repeat markers. Results showed an aggregation pattern dependent on reproductive adults of up to 10 m; however, dependence on sex was restricted to only 3 m, suggesting limited pollen and seed dispersal. Gene neighborhoods did not exceed 10 m, with three well-defined families within the population. The small size of the neighborhoods, high mortality rate of seedlings, and loss of genetic variability in the juvenile category suggest that this population...

In order to elucidate the influence of genetic diversity and microclimatic conditions on Premature Fruit Abortion (PFA) in this study was performed the molecular and microclimatic characterization of two V. planifolia plantations with divergent backgrounds of PFA. The genetic diversity was investigated using microsatellite markers (SSR) and intergenic simple sequence repeats (ISSR) markers. The SSR markers were highly monomorphic and therefore were used only as a reference point to indicate the level of heterozygosity from codominant markers. In contrast, the level of resolution of the ISSR markers in this study was sufficient to distinguish individual differences between the plantations. Overall, the entire analysis performed in this study with ISSR markers pointed to a higher genetic diversity in the El Palmar plantation, which interestingly, does not show evidence of PFA. In this regard, the number of private loci, Shannon’s diversity index and the expected heterozygosity estimates were higher for El Palmar than for Calle Grande. These results are consistent with the information generated by the AMOVA and UPGMA analysis. In addition, the low levels of heterozygocity detected with both markers suggest the likelihood that the V. planifolia are showing a reduction in their adaptive capacity due to inbreeding depression processes. Moreover, the records of environmental conditions in recent years showed that during the periods when the PFA had worsened, the environmental temperatures reached up to 45 °C. Finally, our results of correlation analysis pointed out that a low genetic diversity and high environmental temperatures were significantly associated with PFA.

Mexico was the main vanilla producer worldwide many years ago. However, it currently provides just around 5 % of the global production. The issues that have led to the current stagnation of the vanilla production in Mexico have been addressed from various perspectives, but few studies have included the opinion of smallholder farmers. For this reason, the aim of this study was to conduct a participatory diagnostic to identify the challenges and constraints that affect the vanilla productive sector in Mexico from the smallholder farmers perspective. This study was conducted under the of Participatory Rural Appraisal (PRA) approach; consequently, we used PRA techniques for data collection. The qualitative data obtained were transcribed and analyzed using the Content Analysis Method (CAM) and Constant Comparative Method (CCM). The results showed that most of the challenges and limitations referred to by smallholder farmers result from the lack of training to improve production, processing, and marketing. Likewise, various restrictive aspects were identified in the production process that affect crop productivity, such as cultivation in small parcels, high incidence of diseases, premature abortion of fruits, and low tolerance of plants to stress. An aspect common to all processes is the need to promote organization and training schemes, since under the conditions described for the vanilla production chain in Mexico, relationships have been built in highly competitive communities and, in general, the targets seek have been mutually exclusive. For the above, we consider that achieving more profitable and sustainable production schemes require placing smallholder farmers at the base of an inclusive production system supported by fair trade, with organization, institutions, technology transfer, level of trust, and cooperation as core elements.