Testing morphological trait evolution and assessing species delimitations in the grape genus using a phylogenomic framework.

The grape genus (Vitis L.) is of great agronomic importance and represents an economically valuable resource. Researchers have explored the phylogenetic relationships of subgenus Vitis for decades. However, the evolutionary patterns of many morphological characters of subgenus Vitis have not yet been explored in the context of a robust phylogenetic framework. Within the East Asian clade, V. bryoniifolia and its closely related taxa form the V. bryoniifolia clade, which is taxonomically complex. The phylogenetic relationships and species delimitation within this clade remain poorly resolved, due to the limited sampling in prior studies. We tested morphological trait evolution based on ancestral character state reconstruction using a phylogenomic framework. With 89 accessions from the East Asian subgenus Vitis sampled, a robust phylogenetic relationship of the V. bryoniifolia clade is reconstructed using the restriction-site associated DNA sequencing (RAD-seq) data, which support the monophyly of most taxa of the V. bryoniifolia clade. Ancestral character state reconstructions suggest that the weak climbing ability and simplified tendrils of Vitis each evolved multiple times. This study provides a reliable phylogenomic framework for the V. bryoniifolia clade. Coupled with morphological analyses, we discuss the taxonomic status of some taxa in the V. bryoniifolia clade and untangle a taxonomic dilemma in the grape genus.