Phylogeny of Nolana (Solanaceae) of the Atacama and Peruvian deserts inferred from sequences of four plastid markers and the nuclear LEAFY second intron

Abstract

The phylogeny of Nolana (Solanaceae), a genus primarily distributed in the coastal Atacama and Peruvian deserts with a few species in the Andes and one species endemic to the Galápagos Islands, was reconstructed using sequences of four plastid regions ( ndhF, psbA-trnH, rps16-trnK and trnC-psbM) and the nuclear LEAFY second intron. The monophyly of Nolana was strongly supported by all molecular data. The LEAFY data suggested that the Chilean species, including Nolana sessiliflora, the N. acuminata group and at least some members of the Alona group, are basally diverged, supporting the Chilean origin of the genus. Three well-supported clades in the LEAFY tree were corroborated by the SINE (short interspersed elements) or SINE-like insertions. Taxa from Peru are grouped roughly into two clades. Nolana galapagensis from the Galápagos Island is most likely to have derived from a Peruvian ancestor. The monophyly of the morphologically well-diagnosed Nolana acuminata group ( N. acuminata, N. baccata, N. paradoxa, N. parviflora, N. pterocarpa, N. rupicola and N. elegans) was supported by both plastid and LEAFY data. Incongruence between the plastid and the LEAFY data was detected concerning primarily the positions of N. sessiliflora, N. galapagensis, taxa of the Alona group and the two Peruvian clades. Such incongruence may be due to reticulate evolution or in some cases lineage sorting of plastid DNA. Incongruence between our previous GBSSI trees and the plastid– LEAFY trees was also detected concerning two well-supported major clades in the GBSSI tree. Duplication of the GBSSI gene may have contributed to this incongruence.