Molecular systematics of Poaceae based on eight chloroplast markers, emphasizing the phylogenetic positions of Korean taxa

Abstract

This study was conducted to clarify the phylogenetic position and relationships of Korean Poaceae taxa. A total of 438 taxa including 155 accessions of Korean Poaceae (representing 92% and 72% of Korean Poaceous genera and species, respectively) were employed for phylogeny reconstruction. Sequence data of eight chloroplast DNA markers were used for molecular phylogenetic analyses. The resulted phylogeny was mostly concordant with previous phylogenetic hypotheses, especially in terms of subfamilial and tribal relationships. Several taxa-specific indels were detected in the molecular phylogeny, including a 45 bp deletion in rps3 (PACMAD [Panicoideae, Arundinoideae, Chloridoideae, Micrairoideae, Aristidoideae, Danthonioideae] clade), a 15 bp deletion in ndhF (Oryzeae + Phyllorachideae), a 6 bp deletion in trnLF (Poeae s.l.), and two (17 bp and 378 bp) deletions in atpF-H (Pooideae). The Korean Poaceae members were classified into 23 tribes, representing eight subfamilies. The subfamilial and tribal classifications of the Korean taxa were generally congruent with a recently published system, whereas some subtribes and genera were found to be non-monophyletic. The taxa included in the PACMAD clade (especially Andropogoneae) showed very weak and uncertain phylogenetic relationships, presumably to be due to evolutionary radiation and polyploidization. The reconstructed phylogeny can be utilized to update the taxonomic positions of the newly examined grass accessions.