The phylogenetic relationships of Asparagales in Korea based on five plastid DNA regions

Abstract

We performed a phylogenetic analysis of 13 families of Asparagales sensu APG III, including 59 Korean taxa representing 10 families based on five plastid regions sequences (matK, rbcL, rpoC1, rps3, and atpF-H intergenic spacer). Parsimony and Bayesian analyses were conducted to clarify the relationships among Korean Asparagales. Among the five regions, matK and atpF-H were the most informative. The most congruent phylogenetic trees were obtained from the combinations of four regions excluding atpF-H. Although both the matK and rbcL gene trees implied that the family system of Asparagales sensu APG III should be modified to include three expanded families, our combined four-regions data set resulted in a highly resolved topology with strong support for the following: (1) Asparagaceae s.l.; (2) Amaryllidaceae s.l.; (3) Hemerocallidoideae of Xanthorrhoeaceae s.l.; (4) Iridaceae; (5) Hypoxidaceae; and (6) Orchidaceae. However, the position of Scilla (Scilloideae of Asparagaceae s.l.) was ambiguous. Hemerocallidoideae was a sister group of both the expanded families of Asparagaceae s.l. and Amaryllidaceae s.l., which are considered the core asparagoids, while Orchidaceae was sister to all other Asparagales. We discuss differentiation of the morphological character within the Korean Asparagales, which clearly suggests that the subfamily Nolinoideae of Asparagaceae s.l. exhibits different character states than the other subfamilies. We compared 10 representative morphological characters to the molecular phylogenetic relationships, and propose that the circumscription within Asparagales sensu APG III needs to be reconsidered.