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37 pages, 4233 KiB

Open AccessArticle

Uses, Knowledge and Extinction Risk Faced by Agave Species in Mexico

by Cecilia Alducin-Martínez, Karen Y. Ruiz Mondragón, Ofelia Jiménez-Barrón, Erika Aguirre-Planter, Jaime Gasca-Pineda, Luis E. Eguiarte and Rodrigo A. Medellin

Plants 2023, 12(1), 124; https://doi.org/10.3390/plants12010124 - 27 Dec 2022

Cited by 5 | Viewed by 3525

Abstract

We compiled an updated database of all Agave species found in Mexico and analyzed it with specific criteria according to their biological parameters to evaluate the conservation and knowledge status of each species. Analyzing the present status of all Agave species not only [...] Read more.

We compiled an updated database of all Agave species found in Mexico and analyzed it with specific criteria according to their biological parameters to evaluate the conservation and knowledge status of each species. Analyzing the present status of all Agave species not only provides crucial information for each species, but also helps determine which ones require special protection, especially those which are heavily used or cultivated for the production of distilled beverages. We conducted an extensive literature review search and compiled the conservation status of each species using mainstream criteria by IUCN. The information gaps in the database indicate a lack of knowledge and research regarding specific Agave species and it validates the need to conduct more studies on this genus. In total, 168 Agave species were included in our study, from which 89 are in the subgenus Agave and 79 in the subgenus Littaea. Agave lurida and A. nizandensis, in the subgenus Agave and Littaea, respectively, are severely endangered, due to their endemism, lack of knowledge about pollinators and floral visitors, and their endangered status according to the IUCN Red List. Some species are at risk due to the loss of genetic diversity resulting from production practices (i.e., Agave tequilana), and others because of excessive and unchecked overharvesting of wild plants, such as A. guadalajarana, A. victoriae-reginae, A. kristenii, and others. Given the huge economic and ecological importance of plants in the genus Agave, our review will be a milestone to ensure their future and continued provision of ecosystem services for humans, as well as encouraging further research in Agave species in an effort to enhance awareness of their conservation needs and sustainable use, and the implementation of eco-friendly practices in the species management. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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19 pages, 5605 KiB

Open AccessArticle

Evidence for Light and Tissue Specific Regulation of Genes Involved in Fructan Metabolism in Agave tequilana

by Alan D. Gomez-Vargas, Karen M. Hernández-Martínez, Macrina E. López-Rosas, Gerardo Alejo Jacuinde and June Simpson

Plants 2022, 11(16), 2153; https://doi.org/10.3390/plants11162153 - 19 Aug 2022

Cited by 2 | Viewed by 1875

Abstract

Plant Glycoside Hydrolase Family 32 (PGHF32) contains the fructosyltransferases and fructan exohydrolase enzymes responsible for fructan metabolism, in addition to closely related vacuolar and cell wall acid invertases. Agave species produce complex and dynamic fructan molecules (agavins) requiring 4 different fructosyltransferase activities (1-SST, [...] Read more.

Plant Glycoside Hydrolase Family 32 (PGHF32) contains the fructosyltransferases and fructan exohydrolase enzymes responsible for fructan metabolism, in addition to closely related vacuolar and cell wall acid invertases. Agave species produce complex and dynamic fructan molecules (agavins) requiring 4 different fructosyltransferase activities (1-SST, 1-FFT, 6G-FFT and 6-SFT) for their synthesis. Combined analysis of RNAseq and genome data for A. tequilana led to the characterization of the genes encoding 3 fructosyltransferases for this species and support the hypothesis that no separate 6-SFT type enzyme exists in A. tequilana, suggesting that at least one of the fructosyltransferases identified may have multiple enzymatic activities. Structures for PGHF32 genes varied for A. tequilana and between other plant species but were conserved for different enzyme types within a species. The observed patterns are consistent with the formation of distinct gene structures by intron loss. Promoter analysis of the PGHF32 genes identified abundant putative regulatory motifs for light regulation and tissue-specific expression, and these regulatory mechanisms were confirmed experimentally for leaf tissue. Motifs for phytohormone response, carbohydrate metabolism and dehydration responses were also uncovered. Based on the regulatory motifs, full-length cDNAs for MYB, GATA, DOF and GBF transcription factors were identified and their phylogenetic distribution determined by comparison with other plant species. In silico expression analysis for the selected transcription factors revealed both tissue-specific and developmental patterns of expression, allowing candidates to be identified for detailed analysis of the regulation of fructan metabolism in A. tequilana at the molecular level. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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17 pages, 4488 KiB

Open AccessArticle

Agave Fructans in Oaxaca’s Emblematic Specimens: Agave angustifolia Haw. and Agave potatorum Zucc.

by Ruth E. Márquez-López, Patricia Araceli Santiago-García and Mercedes G. López

Plants 2022, 11(14), 1834; https://doi.org/10.3390/plants11141834 - 13 Jul 2022

Cited by 6 | Viewed by 2275

Abstract

Despite the recognition of Agave tequilana Weber var. Azul as raw material for producing tequila and obtaining prebiotics, there are other highly relevant Agave species in Mexico. Oaxaca contains a startlingly diverse range of Agave species; Agave angustifolia Haw. and Agave potatorum Zucc. [...] Read more.

Despite the recognition of Agave tequilana Weber var. Azul as raw material for producing tequila and obtaining prebiotics, there are other highly relevant Agave species in Mexico. Oaxaca contains a startlingly diverse range of Agave species; Agave angustifolia Haw. and Agave potatorum Zucc. are two classic specimens with great commercial potential. In this study, we examined the fructan fluctuation in these two species during their lifetime in the field (from 1 to 6 years old). First, we analyzed their morphological diversity based on vegetative characteristics. Subsequently, fructan extracts were analyzed by TLC, FT-IR, and HPAEC-PAD to identify carbohydrates. Multivariate analyses of the morphological parameters indicated a morphological divergence between the two species. Furthermore, we found that the concentration of simple carbohydrates and fructans, as well as the fructan DP, changed during plant development. Glucose, fructose, and fructooligosaccharides (FOS) were more abundant in A. potatorum, while A. angustifolia showed a greater amount of sucrose and fructans with a high DP. Fructan DP heatmaps were constructed using HPAEC-PAD profiles—the heatmaps were very helpful for establishing an easy correlation between age and the carbohydrate types present in the fructan extracts. This study is an important contribution to the agave fructan knowledge of the Mexican agave diversity. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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21 pages, 3240 KiB

Open AccessArticle

Transcriptome Mining Provides Insights into Cell Wall Metabolism and Fiber Lignification in Agave tequilana Weber

by Luis F. Maceda-López, Elsa B. Góngora-Castillo, Enrique Ibarra-Laclette, Dalia C. Morán-Velázquez, Amaranta Girón Ramírez, Matthieu Bourdon, José L. Villalpando-Aguilar, Gabriela Toomer, John Z. Tang, Parastoo Azadi, Jorge M. Santamaría, Itzel López-Rosas, Mercedes G. López, June Simpson and Fulgencio Alatorre-Cobos

Plants 2022, 11(11), 1496; https://doi.org/10.3390/plants11111496 - 02 Jun 2022

Cited by 2 | Viewed by 2373

Abstract

Resilience of growing in arid and semiarid regions and a high capacity of accumulating sugar-rich biomass with low lignin percentages have placed Agave species as an emerging bioenergy crop. Although transcriptome sequencing of fiber-producing agave species has been explored, molecular bases that control [...] Read more.

Resilience of growing in arid and semiarid regions and a high capacity of accumulating sugar-rich biomass with low lignin percentages have placed Agave species as an emerging bioenergy crop. Although transcriptome sequencing of fiber-producing agave species has been explored, molecular bases that control wall cell biogenesis and metabolism in agave species are still poorly understood. Here, through RNAseq data mining, we reconstructed the cellulose biosynthesis pathway and the phenylpropanoid route producing lignin monomers in A. tequilana, and evaluated their expression patterns in silico and experimentally. Most of the orthologs retrieved showed differential expression levels when they were analyzed in different tissues with contrasting cellulose and lignin accumulation. Phylogenetic and structural motif analyses of putative CESA and CAD proteins allowed to identify those potentially involved with secondary cell wall formation. RT-qPCR assays revealed enhanced expression levels of AtqCAD5 and AtqCESA7 in parenchyma cells associated with extraxylary fibers, suggesting a mechanism of formation of sclerenchyma fibers in Agave similar to that reported for xylem cells in model eudicots. Overall, our results provide a framework for understanding molecular bases underlying cell wall biogenesis in Agave species studying mechanisms involving in leaf fiber development in monocots. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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12 pages, 2899 KiB

Open AccessEditor’s ChoiceArticle

Phylogeny and Expression Atlas of the NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY in Agave

by Shibei Tan, Yanqiong Liang, Yanlei Huang, Jingen Xi, Xing Huang, Xiaohan Yang and Kexian Yi

Plants 2022, 11(11), 1434; https://doi.org/10.3390/plants11111434 - 27 May 2022

Cited by 5 | Viewed by 1726

Abstract

Agave species are widely cultivated crassulacean acid metabolism (CAM) plants for alcoholic beverages, food and fiber production. Among these, the Agave hybrid H11648 ((A. amaniensis × A. angustifolia) × A. amaniensis) is the main cultivar for sisal fiber in the [...] Read more.

Agave species are widely cultivated crassulacean acid metabolism (CAM) plants for alcoholic beverages, food and fiber production. Among these, the Agave hybrid H11648 ((A. amaniensis × A. angustifolia) × A. amaniensis) is the main cultivar for sisal fiber in the tropical areas of Brazil, China, and African countries. The plants of Agave hybrid H11648 have a long life cycle and large leaves, which require a huge amount of nitrogen nutrient. However, the molecular basis of nitrogen transport and allocation has not been well understood in agave. In this study, we identified 19 NITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER FAMILY(NPF) genes (called AhNPFs) with full-length coding sequences in Agave hybrid H11648. Our analysis of gene expression in various types of tissues revealed the tissue-specific expression pattern of AhNPFs. We further examined their expression patterns at different leaf developmental stages, under abiotic/biotic stresses and nutrient deficiency. The results reveal several candidate regulators in the agave NPF family, including AhNPF4.3/5.2/7.1. We first characterized the NPF genes in agave based on published leaf transcriptome datasets and emphasized their potential functions. The study will benefit future studies related to nitrogen nutrient in agave. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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20 pages, 2420 KiB

Open AccessArticle

Genomic Analyses of Wild and Cultivated Bacanora Agave (Agave angustifolia var. pacifica) Reveal Inbreeding, Few Signs of Cultivation History and Shallow Population Structure

by Anastasia Klimova, Karen Y. Ruiz Mondragón, Francisco Molina Freaner, Erika Aguirre-Planter and Luis E. Eguiarte

Plants 2022, 11(11), 1426; https://doi.org/10.3390/plants11111426 - 27 May 2022

Cited by 6 | Viewed by 2183

Abstract

Due to the recent increase in demand for agave-based beverages, many wild agave populations have experienced rapid decline and fragmentation, whereas cultivated plants are now managed at monocultural plantations, in some cases involving clonal propagation. We examined the relative effect of migration, genetic [...] Read more.

Due to the recent increase in demand for agave-based beverages, many wild agave populations have experienced rapid decline and fragmentation, whereas cultivated plants are now managed at monocultural plantations, in some cases involving clonal propagation. We examined the relative effect of migration, genetic drift, natural selection and human activities on the genetic repertoire of Agave angustifolia var. pacifica, an agave used for bacanora (an alcoholic spirit similar to tequila) production in northwestern Mexico. We sampled 34 wild and cultivated sites and used over eleven thousand genome-wide SNPs. We found shallow genetic structure among wild samples, although we detected differentiation between coastal and inland sites. Surprisingly, no differentiation was found between cultivated and wild populations. Moreover, we detected moderate inbreeding (F_IS ~ 0.13) and similar levels of genomic diversity in wild and cultivated agaves. Nevertheless, the cultivated plants had almost no private alleles and presented evidence of clonality. The overall low genetic structure in A. angustifolia var. pacifica is apparently the result of high dispersibility promoted by pollinators and the possibility of clonal reproduction. Incipient cultivation history and reliance on wild seeds and plants are probably responsible for the observed patterns of high genetic connectivity and considerable diversity in cultivated samples. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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Review

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10 pages, 2173 KiB

Open AccessReview

Agave americana: Characteristics and Potential Breeding Priorities

by Sarah C. Davis

Plants 2022, 11(17), 2305; https://doi.org/10.3390/plants11172305 - 02 Sep 2022

Cited by 3 | Viewed by 2966

Abstract

Agave americana L. is one of many Agave species that could be developed for the production of valuable agricultural products. Although all species in this genus use Crassulacean Acid Metabolism (CAM) and most have drought and heat tolerance, Agave americana also has the [...] Read more.

Agave americana L. is one of many Agave species that could be developed for the production of valuable agricultural products. Although all species in this genus use Crassulacean Acid Metabolism (CAM) and most have drought and heat tolerance, Agave americana also has the combined traits of high yield and cold tolerance. This review highlights key characteristics of Agave americana that make it an exceptional novel crop for fiber, sweeteners, bioproducts, and bioethanol with resilient traits for changing climate conditions. Then, it proposes potential directions for breeding that will support production in semi-arid climates. With selection and breeding, yields of 16 Mg ha⁻¹ y⁻¹ may be achieved. Current field observations, with no crop improvement, indicate ~9 Mg ha⁻¹ is the maximum yield, and in arid regions, a yield of ~3 Mg ha⁻¹ y⁻¹ is observed. It may be beneficial to breed for a shorter time to flowering, as has been successful for Agave tequilana Weber var. azul, so that further breeding goals are achievable in a decadal timespan. Specific trait selection during breeding will depend on whether fiber or sugar yields are the desired products at a given location. Even without breeding, varieties of Agave americana are climate resilient alternatives for some current commodity crops. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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12 pages, 1320 KiB

Open AccessReview

Advances in the Micropropagation and Genetic Transformation of Agave Species

by Erika Bautista-Montes, Laura Hernández-Soriano and June Simpson

Plants 2022, 11(13), 1757; https://doi.org/10.3390/plants11131757 - 01 Jul 2022

Cited by 7 | Viewed by 3251

Abstract

The Agave genus is composed of approximately 210 species distributed from south United States to Colombia and Venezuela. Numerous Agave species have been used for the preparation of alcoholic beverages and have attracted interest in the pharmaceutical and food industry. Despite their economic [...] Read more.

The Agave genus is composed of approximately 210 species distributed from south United States to Colombia and Venezuela. Numerous Agave species have been used for the preparation of alcoholic beverages and have attracted interest in the pharmaceutical and food industry. Despite their economic importance, there are few initiatives for the improvement and selection of characteristics of interest. This is mainly due to its morphology, long lifecycles, and monocarpic nature. Micropropagation is a feasible alternative to the improvement of Agave species. It has been used for multiple purposes, including massive propagation, induction of somaclonal variation to enhance agronomic characteristics of interest, maintenance of specific genotypes, and genetic transformation using molecular techniques. In this report, we summarize the most outstanding findings regarding the micropropagation of Agave species mediated by multiple regeneration responses. We also describe the media and growth regulators for each of the previously described methods. In addition, we discuss how micropropagation has allowed the development of transformation protocols. Exploitation of this technology may be a feasible strategy to introduce genes and improve certain traits. Genetic transformation also offers an opportunity for studying molecular mechanisms. This represents advantages for optimizing production in the field and for implementing breeding programs. Full article

(This article belongs to the Special Issue Germplasm Resources and Breeding of Agave)

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