Phylogenomic insights into the Fascicularia-Ochagavia group (Bromelioideae, Bromeliaceae)

Abstract

Ochagavia (four species) and Fascicularia (one species) form a well-supported clade of the early-diverging Bromelioideae. The two genera are morphologically similar, but they can be easily discerned on the basis of generative characters. Besides the species distributed on the Chilean mainland, the group includes O. elegans, endemic to the Robinson Crusoe Island of the Juan Fernández Islands. In previous molecular phylogenetic studies, O. elegans formed a sister clade to the remainder of Fascicularia and Ochagavia. A phylogenomic approach, including nearly complete and, in five cases, full plastomes (c. 160 kbp) and the nuclear rDNA cistron (c. 6 kbp), and scanning electron microscope (SEM) images of pollen were used to analyse relationships in the Fascicularia-Ochagavia group. Plastome and nuclear trees were largely congruent and supported previous phylogenetic analyses of O. elegans being sister to the remainder of the group. A divergent phylogenetic position was suggested for O. carnea using different organellar trees. SEM analysis of pollen supported the division of Fascicularia and Ochagavia. Evolutionary and taxonomic implications of our results are discussed.