Biosystematic Studies on Lilium (Liliaceae) I. Phylogenetic Analysis Based on Chloroplast and Nuclear DNA Sequences and a Revised Infrageneric Classification

Abstract

Based on molecular phylogenetic evidence, phylogenetic analyses of both cpDNA and nrDNA sequences based on 76 (cp) and 77 (nr) samples representing 64 species, two subspecies, and three (cp) and two (nr) varieties of Lilium and six (cp) and five (nr) samples from Cardiocrinum, Fritillaria, and Notholirion as outgroups were used to better understand relationships within Lilium and to revise its infrageneric classification. The same individuals were used for both cpDNA and nrDNA analyses to avoid confusion caused by genetic polymorphism within a species. Nine thousand eight hundred thirty seven bp from 10 cpDNA regions and 1069 bp from the nuclear (ITS + ETS) regions were analyzed. The same twelve clades were formed in Lilium in both the chloroplast and nuclear trees (one clade of the former tree and one clade of the latter tree were not strictly formed because of low resolution). In light of the cpDNA and nrDNA trees obtained, 13 morphological characters, including a pair of marginal ridges along a central groove on the adaxial surface of the tepals were examined with attention given for the first time to the use of this character as having diagnostic value. The morphological evidence supported the twelve clades. Based on molecular and morphological evidence, a revised infrageneric classification of Lilium recognizing twelve clades as twelve sections is proposed.