Phylogenomic analyses support a new subgenus Rojovitis of the grape genus Vitis from Mexico

Jun Wen^1,2*Angélica Quintanar Castillo³Marcelo R. Pace⁴Alicia Talavera²Luke Sparreo²Gabriel Johnson²Gary Krupnick²Zelong Nie²

• ¹Smithsonian Institution, Washington, United States
• ²Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington DC, United States
• ³Institute of Biology, National Autonomous University of Mexico, Mexico City, México, Mexico
• ⁴nstituto de Biología, Universidad Nacional Autónoma de México, Mexico City, Mexico

In spite of the tremendous economic significance of grapes, the systematics of the grape genus remains under-studied. Based on recent field work, phylogenomic analyses using both nuclear and plastid genomes as well as morphological comparisons, we report a new grape subgenus Rojovitis endemic to Mexico. The new subgenus constitutes a clade, which diverged early in the evolutionary history of Vitis, yet there is cytonuclear discordance in its position, suggesting hybridization as a likely mechanism in its origin. The subgenus Rojovitis contains two species, Vitis martineziana J. Wen from Chiapas and V. rubriflora J. Wen from Jalisco, both new to science. In comparison to the two other subgenera of the grape genus (subgenus Vitis and subgenus Muscadinia), subgenus Rojovitis is characterized by its red flowers and stems with prominent lenticels. The discovery of the third subgenus in Vitis after nearly a century since the recognition of the second subgenus Muscadinia in 1927 represents a major milestone in the systematic research of grapes and their wild relatives. We also use fieldwork and herbarium data to provide distribution maps and conservation assessments of V. martineziana and V. rubriflora based on IUCN criteria. Both species are assessed to be Critically Endangered. These findings support Mexico as an important region for wild grape resources. The study also showcases that biodiversity discovery is far from being complete today and that field exploration remains critical for biodiversity science and conservation. These newly discovered resources may benefit humanity, yet these species urgently need to be protected and properly managed due to extensive habitat loss and alteration.