Systematics of Vriesea (Bromeliaceae): phylogenetic relationships based on nuclear gene and partial plastome sequences

Abstract

Abstract Vriesea is the second largest genus in Tillandsioideae, the most diverse subfamily of Bromeliaceae. Although recent studies focusing on Tillandsioideae have improved the systematics of Vriesea, no consensus has been reached regarding the circumscription of the genus. Here, we present a phylogenetic analysis of core Tillandsioideae using the nuclear gene phyC and plastid data obtained from genome skimming. We investigate evolutionary relationships at the intergeneric level in Vrieseeae and at the intrageneric level in Vriesea s.s. We sampled a comprehensive dataset, including 11 genera of Tillandsioideae and nearly 50% of all known Vriesea spp. Using a genome skimming approach, we obtained a 78 483-bp plastome alignment containing 35 complete and 55 partial protein-coding genes. Phylogenetic trees were reconstructed using maximum-likelihood based on three datasets: (1) the 78 483 bp plastome alignment; (2) the nuclear gene phyC and (3) a concatenated alignment of 18 subselected plastid genes + phyC. Additionally, a Bayesian inference was performed on the second and third datasets. These analyses revealed that Vriesea s.s. forms a well-supported clade encompassing most of the species of the genus. However, our results also identified several remaining issues in the systematics of Vriesea, including a few species nested in Tillandsia and Stigmatodon. Finally, we recognize some putative groups within Vriesea s.s., which we discuss in the light of their morphological and ecological characteristics.