Conservation genomics of Agave tequilana Weber var. azul: low genetic differentiation and heterozygote excess in the tequila agave from Jalisco, Mexico

PeerJ

article

Karen Yazmin Ruiz Mondragon¹  Erika Aguirre-Planter¹  Jaime Gasca-Pineda¹  Anastasia Klimova¹  Roberto-Emiliano Trejo-Salazar¹  Marco Antonio Reyes Guerra¹  Rodrigo A. Medellin¹  Daniel Piñero¹  Rafael Lira²  Luis E. Eguiarte¹ 

[1] Instituto de Ecología, Universidad Nacional Autónoma de México;Laboratorio de Recursos Naturales, Unidad de Biotecnología y Prototipos ,(UBIPRO), Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México

关键词: Clonality;    Gene flow;    Genetic resources;    Genomic diversity;    Inbreeding;    Single nucleotide polymorphisms (SNPs);   

DOI  :  10.7717/peerj.14398

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Background Genetic diversity is fundamental for the survival of species. In particular, in a climate change scenario, it is crucial that populations maintain genetic diversity so they can adapt to novel environmental conditions. Genetic diversity in wild agaves is usually high, with low genetic differentiation among populations, in part maintained by the agave pollinators such as the nectarivorous bats. In cultivated agaves, patterns of genetic diversity vary according to the intensity of use, management, and domestication stage. In Agave tequilana Weber var. azul (A. tequilana thereafter), the plant used for tequila production, clonal propagation has been strongly encouraged. These practices may lead to a reduction in genetic diversity. Methods We studied the diversity patterns with genome-wide SNPs, using restriction site associated DNA sequencing in cultivated samples of A. tequilana from three sites of Jalisco, Mexico. For one locality, seeds were collected and germinated in a greenhouse. We compared the genomic diversity, levels of inbreeding, genetic differentiation, and connectivity among studied sites and between adults and juvenile plants. Results Agave tequilana presented a genomic diversity of HT = 0.12. The observed heterozygosity was higher than the expected heterozygosity. Adults were more heterozygous than juveniles. This could be a consequence of heterosis or hybrid vigor. We found a shallow genetic structure (average paired FST = 0.0044). In the analysis of recent gene flow, we estimated an average migration rate among the different populations of m = 0.25. In particular, we found a population that was the primary source of gene flow and had greater genomic diversity (HE and HO), so we propose that this population should continue to be monitored as a potential genetic reservoir. Discussion Our results may be the consequence of more traditional management in the studied specific region of Jalisco. Also, the exchange of seeds or propagules by producers and the existence of gene flow due to occasional sexual reproduction may play an important role in maintaining diversity in A. tequilana. For populations to resist pests, to continue evolving and reduce their risk of extinction under a climate change scenario, it is necessary to maintain genetic diversity. Under this premise we encourage to continue acting in conservation programs for this species and its pollinators.

【 授权许可】

CC BY