Laura Trejo

Selling pulque requires extensive knowledge of its handling, mainly learned through oral communication. Its uses and related customs have been little described outside production sites in Tlaxcala. Therefore, this work has documented the traditional knowledge of pulque handling at the points of sale (POS) in Tlaxcala, one of the main producers of this beverage in Mexico. Economic data on the sale of pulque and the descriptions of sellers and customers are also provided. Semistructured interviews were conducted in 131 POS in 93% of Tlaxcala's municipalities using snowball sampling. The results describe management activities in the POS of pulque, aguamiel, and cured pulque, such as cold or room temperature storage. Pulque is sold within most of Tlaxcala, but its production and sale are greatest in the northern part. Pulque sales constitute a job opportunity for adults, mostly men who sell in pulquerías (63%). Pulque is sold by producers (64% > 60 years old) in their homes (50%) and pulquerías (22%). Half the pulque is resold mainly in pulquerías (57%) and homes (12%). A total of 84% of the establishments are less than 20 years old, and service is provided every day, with working hours exceeding 7 h. The price of pulque varies widely, since it can be sold from $0.26 to $5.16 per liter. This variability is possibly associated with the type of POS. Customers prefer sweet pulque, and more than half the consumers are male (55%). This work is a guideline for future state censuses of pulque production and sale.

Antecedentes y Objetivos: El maguey pulquero (Agave salmiana) del altiplano central de México representa historia, cultura y riqueza. En Tlaxcala se siembran preferentemente cuatro cultivares de Agave salmiana subsp. salmiana: Ayoteco, Chalqueño, Manso y Púa Larga. Su uso está limitado a la producción de pulque y actualmente no hay información sobre la composición química que pueda ayudar a los agricultores a seleccionar los ejemplares dependiendo de su propósito. El objetivo de esta investigación fue evaluar el perfil de biomoléculas producidas por estos cuatro cultivares.Métodos: Se evaluó la producción de biomoléculas en cuatro cultivares de la subespecie salmiana a través de un diseño experimental de dos factores: cultivar y etapa fenológica, con cuatro niveles para cada factor. Las variables respuesta fueron: el contenido de inulina (INU), fructooligosacáridos (FOS), azúcares reductores directos (ARD), azúcares reductores totales (ART), ácidos grasos (AG), ésteres (ES) y otras moléculas.Resultados clave: El análisis factorial mostró que, para ART, FOS e INU, las diferencias contrastantes fueron entre las etapas fenológicas capón y edad media. El análisis de componentes principales indicó que el componente uno está representado por los ART, FOS y INU y que hay una alta correlación (>0.8) de los ART con los FOS y INU. El componente dos representó los grados de polimerización promedio (GPP), tanto de la INU como de los FOS. Por su parte, el análisis de CG-MSD permitió la identificación tentativa de moléculas con potencial uso. Conclusiones: Los resultados podrían servir para aprovechar de manera estratégica los diferentes cultivares de Agave del altiplano central de México.

Agave is one of the most important genera of plants in Mexico in terms of biodiversity and cultural and economic impact; however, its reproductive traits and breeding systems are poorly known. In addition, clonal propagation of agave cultures and the interruption of sexual reproduction may lead to differences not only in reproductive traits but also in seed set and seed viability across species and between wild plants and Agave landraces. Hence this research evaluated the morphological variation of flowers, fruits, and seeds throughout the infructescence development of pulquero agave landraces (Agave americana, A. mapisaga, and A. salmiana) and their wild relatives (A. salmiana) using statistical analyses. Additionally, seed set and seed viability (tetrazolium test) were estimated for traditional (metepantle) and intensive (monoculture) cultivation systems. The analysis of flowers allowed differentiating between species (A. mapisaga and A. salmiana), while the analysis of fruits separated wild from cultivated plants. Wild agaves attained seed set values close to 0.5, and cultivated agaves, less than 0.2; the lowest seed set values (0.04) were observed under monoculture. Seed viability percentages depended on the taxon analyzed, with no clear differences between wild and cultivated taxa. There were positive correlations between branch length, fruit number, black (potentially viable) seed number, and the percentage of viable seeds. The highest percentage of viable seeds was recorded in the low and middle parts of the infructescence. Our results demonstrate that reproductive traits are suitable for recognizing morphological groups across species and between wild and landrace agaves. They also show that intensive and prolonged clonal propagation is associated with low seed set and seed viability values in Agave landraces.

There is scarce information available about how peasants recognize Agave landraces. This study aims to identify the agave species and landraces used for “pulque” production and analyze their morphological variability in a Nahualt community, San Pedro Tlacuapan (SPT), Tlaxcala, Mexico. To this end, we used traditional knowledge and conventional statistical methods. Semi-structured interviews were administered; from these, the frequency of mentions, lexical marking, and perception about each landrace were evaluated. A total of 36 morphological vegetative characters were measured in the main landraces, and ordination analyses (PCA) were performed. SPT is home to 8 landraces of Agave americana and Agave salmiana subsp. salmiana. “Manso” was the most frequently mentioned landrace, and 5 qualitative characters used by local experts to identify landraces were observed. One morphological cluster was associated with each landrace analyzed, and the variables characterizing them are rosette size, leaf shape, number of leaves, and tooth shape. The information about agave diversity from local experts can be integrated into measurements of morphological diversity through conventional statistical methods.

Pulque is a product made from the fermentation of the sap (aguamiel ) of certain agaves and its consumption has been recorded since pre-Hispanic times. The effort to recognize the landraces of the Agave genus used to produce pulque and the study of its traditional knowledge remain limited. Studies regarding this topic have centered on farmers (experts) with the biggest production capacity. This work analyzes in different ways the knowledge that experts and non-experts (general population) have regarding the usage and management of agave landraces in Nanacamilpa, Tlaxcala, one of the most iconic pulque production locations in Mexico. Two-hundred and twenty-two semi-structured interviews were carried out with non-experts and 22 with experts. The non-experts recognized 12 agave landraces, whilst experts recognized eight landraces that are mainly used to obtain aguamiel. The most important landrace that they identified was the Agave salmiana, due to the sweetness of its aguamiel and flexibility of its leaves. In total, 92 uses of agave landraces were recorded: 64 direct uses and 28 derivative uses. The oldest participants know most of its uses, but the younger participants recorded 48 uses, which indicates that agaves are a valuable resource for new generations. Experts mentioned uses directly related to the production of plants, aguamiel, and pulque, whilst non-experts included more categories of use. The agaves used for the production of pulque are of great importance for local biodiversity, culture, and economy.

Together with their undeniable role in the ecology of arid and semiarid ecosystems, Agave species are emerging as a model to dissect the relationships between crassulacean acid metabolism and high efficiency of light and water use, and as an energy crop for bioethanol production. Transcriptome resources from economically valuable Agaves species, such as Agave tequilana and A. salmiana, as well as hybrids for fibers, are now available, and multiple gene expression landscape analyses have been reported. Key components in molecular mechanisms underlying drought tolerance could be uncovered by analyzing gene expression patterns of roots. This study describes an efficient protocol for high-quality total RNA isolation from phenolic compounds-rich Agave roots. Our methodology involves suitable root handling and collecting in the field and using saving-time commercial kits available. RNA isolated from roots free of lignified out-layers and clean cortex showed high values of quality and integrity according to electrophoresis and microfluidics-based platform. Synthesis of long full-length cDNAs and PCR amplification tested the suitability for downstream applications of extracted RNA. The protocol was applied successfully to A. tequilana roots but can be used for other Agave species that also develop lignified epidermis/exodermis in roots.

Spines are key plant modifications developed to deal against herbivores; however, its physical structure and chemical composition have been little explored in plant species. Here, we took advantage of high-throughput chromatography to characterize chemical composition of Agave fourcroydes Lem. spines, a species traditionally used for fiber extraction. Analyses of structural carbohydrate showed that spines have lower cellulose content than leaf fibers (52 and 72%, respectively) but contain more than 2-fold the hemicellulose and 1.5-fold pectin. Xylose and galacturonic acid were enriched in spines compared to fibers. The total lignin content in spines was 1.5-fold higher than those found in fibers, with elevated levels of syringyl (S) and guaiacyl (G) subunits but similar S/G ratios within tissues. Metabolomic profiling based on accurate mass spectrometry revealed the presence of phenolic compounds including quercetin, kaempferol, (+)-catechin, and (−)-epicatechin in A. fourcroydes spines, which were also detected in situ in spines tissues and could be implicated in the color of these plants’ structures. Abundance of (+)-catechins could also explain proanthocyanidins found in spines. Agave spines may become a plant model to obtain more insights about cellulose and lignin interactions and condensed tannin deposition, which is valuable knowledge for the bioenergy industry and development of naturally dyed fibers, respectively.

Pulque is one of the oldest fermented beverages, with its origins dating back to pre-Hispanic Mexico. Recently, public consumption has increased. However, the majority of Agave plantations for pulque production have disappeared or been abandoned in recent decades. To create strategies for the conservation and production of pulque agaves, it is necessary to first determine their taxonomic identities and to better understand their genetic and morphological diversity. Despite the historical importance of pulque in Mexico, little attention has been placed on the study of Agave plants used for its production. Therefore, we analyzed the morphological diversity of vegetative characters of nine landraces of two Agave species (A. salmiana and A. mapisaga) which are widely cultivated for pulque production in Tlaxcala, Mexico. The analysis of morphological characters showed that the landraces largely clustered based on classic taxonomic relationships. One cluster of landraces associated with Agave mapisaga var. mapisaga and another with A. salmiana subsp. salmiana, but with the exception of A. salmiana subsp. salmiana “Ayoteco”, which is more closely related with A. mapisaga var. mapisaga. Additionally, we analyzed the genetic relationships between 14 landraces and wild individuals using molecular markers (trnL and ITS). The identified genetic variants or haplotypes and genetic pools mainly corresponded with the species. In the case of “Ayoteco”, incongruence between markers was observed. Low selection intensity, genetic flow events, and the plasticity of morphological traits may explain the high number of landraces without clear differences in their morphological diversity (vegetative characters) or genetic pools. The use of reproductive traits and massive sequencing might be useful for identifying possible morphological and genetic changes in the Agave landraces used for pulque production.