DNA barcoding of Gaultheria L.in China (Ericaceae: Vaccinioideae)

Four DNA barcoding loci,chloroplast loci rbcL,matK,trnH-psbA,and nuclear locus internal transcribed spacer (ITS),were tested for the accurate discrimination of the Chinese species of Gaultheria by using intraspecific and interspecific pairwise P-distance,Wilcoxon signed rank test,and tree-based analyses.This study included 186 individuals from 89 populations representing 30 species.For all individuals,single locus markers showed high levels of sequencing universality but were ineffective for species resolvability.Polymerase chain reaction amplification and sequencing were successful for all four loci.Both ITS and matK showed significantly higher levels of interspecific species delimitation than rbcL and trnH-psbA.A combination ofmatK and ITS was the most efficient DNA barcode among all studied regions,however,they do not represent an appropriate candidate barcode for Chinese Gaultheria,by which only 11 out of 30 species can be separated.Loci rbcL,matK,and trnH-psbA,which were recently proposed as universal plant barcodes,have a very poor capacity for species separation for Chinese Gaultheria.DNA barcodes may be reliable tools to identify the evolutionary units of this group,so further studies are needed to develop more efficient DNA barcodes for Gaultheria and other genera with complicated evolutionary histories.     

DNA barcoding of Gaultheria L. in China (Ericaceae: Vaccinioideae)

Abstract Four DNA barcoding loci, chloroplast loci rbcL, matK, trnH‐psbA, and nuclear locus internal transcribed spacer (ITS), were tested for the accurate discrimination of the Chinese species of Gaultheria by using intraspecific and interspecific pairwise P‐distance, Wilcoxon signed rank test, and tree‐based analyses. This study included 186 individuals from 89 populations representing 30 species. For all individuals, single locus markers showed high levels of sequencing universality but were ineffective for species resolvability. Polymerase chain reaction amplification and sequencing were successful for all four loci. Both ITS and matK showed significantly higher levels of interspecific species delimitation than rbcL and trnH‐psbA. A combination of matK and ITS was the most efficient DNA barcode among all studied regions, however, they do not represent an appropriate candidate barcode for Chinese Gaultheria, by which only 11 out of 30 species can be separated. Loci rbcL, matK, and trnH‐psbA, which were recently proposed as universal plant barcodes, have a very poor capacity for species separation for Chinese Gaultheria. DNA barcodes may be reliable tools to identify the evolutionary units of this group, so further studies are needed to develop more efficient DNA barcodes for Gaultheria and other genera with complicated evolutionary histories.     

Systematic implications of seed coat diversity in Gaultherieae (Ericaceae)

The seed morphology of 90 samples from 83 species of tribe Gaultherieae (Chamaedaphne, Diplycosia, Eubotryoides, Eubotrys, Gaultheria and Leucothoe) and relatives in tribes Andromedeae (Andromeda and Zenobia) and Vaccinieae (Satyria) was investigated with stereoscopic and scanning electron microscopy. Seeds exhibit variation in shape, colour, size, wing, hilum region, primary ornamentation and epidermal cells. Non‐metric multidimensional scaling (NMDS) analysis based on selected seed characters supports the affinities of some groups within Gaultherieae at various taxonomic levels. Seed characters corroborate the delimitation of Andromeda, Chamaedaphne, Leucothoe, Satyria and Zenobia and Gaultheria series Trichophyllae, series Hispidulae, section Amblyandra and section Brossaeopsis. Parsimony optimization of seed characters onto a previously published phylogenetic estimate of Gaultherieae reveals that small seeds have evolved from larger seeds and an areolate seed coat has evolved from a reticulate seed coat. Optimization also suggests that several seed character states are synapomorphies or potential synapomorphies for some major clades of Gaultherieae. Seeds of Gaultherieae from East Asia, temperate North America and the Pacific are more diverse than those from tropical America. Samples from the eastern Himalaya possess the highest variation in seed morphology. The wing and bulging edge cells observed in seeds of Leucothoe suggest dispersal by wind. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 477–495.