Abstract

Paeonia is a phylogenetically and taxonomically complex group. In this study, two chloroplast coding region of the matK and rbcL genes, two intergenic spacers, 5’ trnK-matKand matK-3’ trnK, the ribosomal RNA 18S and 5S genes, and the nuclear ribosomal DNA ITS gene were sequenced to study phylogenetic relationships of four Paeonia species. In the matK coding region, most nucleotide variations pointed at the divergence betweenPaeonia suffruticosa (MO) and other three species, strongly supporting the phylogenetic evolution of section Paeonia and section Moutan in the Paeonia genus; the variable sites ofPaeonia lactiflora CHA1 accession compared to CHA accession were all identical toPaeonia obovata SHAN accession, indicating that CHA1 might be a hybrid result of CHA and SHAN. Another chloroplast coding region, rbcL showed lower variation rate and less phylogenetic information than the matK region in all four Paeonia species investigated in this study, while the 5S rRNA gene and nrDNA ITS region showed higher variation rate. However, combined phylogenetic relationship of all four peony species is more clearer than any single-locus one. This study would provide more sequence sources of peony species and help further understanding of the phylogenetic relationship.

Key words: Deoxyribonucleic acid (DNA) barcoding, matK, nuclear ribosomaldeoxyribonucleic acid internal transcribed spacer (nrDNA ITS), Paeonia, phylogeny, ribulose-bisphosphate carboxylase (rbcL), 5S ribosomal ribonucleic acid (rRNA).