Phylogenetic analysis of subgenus Dieramalpinia (Alpinia carolinensis clade) - Zingiberaceae based on ITS sequences

Abstract

The most recent infra-generic classification of Alpinia Roxb. by Smith divided the genus into two subgenera (Alpinia and Dieramalpinia) with 11 sections and 12 subsections. One of the sections of Alpinia subgenus Dieramalpinia is Myriocrater which contains about 16 species. The most recent phylogenetic study that included species from Alpinia subgenus Dieramalpinia was done by Kress et al. (2007). They sampled only eight species and found that these were nested within a clade referred to as the Alpinia carolinensis clade. This clade was well supported and may be separated as a genus if sampling more species confirms the result. The objectives of the present project are to compare ITS within one species; to test the monophyly of Alpinia section Myriocrater; to test whether adding more samples still supports the Alpinia carolinensis clade. The present study included thirty-nine samples representing nineteen taxa from Alpinia; seven samples are still unidentified at species level. Sequences of the Internal Transcribed Spacer were used in the analysis. The result showed that ITS sequence of Myriocrater’s species are more conserved than another group in Zingiberaceae. There are base variations within species level. The Alpinia section Myriocrater plus five species from other section is not monophyletic. The Alpinia carolinensis clade still includes three sections of Smith classification (Dieramalpinia, Myriocrater and Pycnanthus) from subgenus Dieramalpinia. Alpinia subgenus Dieramalpinia section Eubractea and one species of section Dieramalpinia are separated into another clade.