DNA barcoding involves sequencing a standard region of DNA as a tool for species identification. However, there has been no agreement on which region(s) should be used for barcoding land plants. To provide a community recommendation on a standard plant barcode, we have compared the performance of 7 leading candidate plastid DNA regions (atpF-atpH spacer, matK gene, rbcL gene, rpoB gene, rpoC1 gene, psbK-psbI spacer, and trnH-psbA spacer). Based on assessments of recoverability, sequence quality, and levels of species discrimination, we recommend the 2-locus combination of rbcL؉matK as the plant barcode. This core 2-locus barcode will provide a universal framework for the routine use of DNA sequence data to identify specimens and contribute toward the discovery of overlooked species of land plants.matK ͉ rbcL ͉ species identification L arge-scale standardized sequencing of the mitochondrial gene CO1 has made DNA barcoding an efficient species identification tool in many animal groups (1). In plants, however, low substitution rates of mitochondrial DNA have led to the search for alternative barcoding regions. From initial investigations of plastid regions (2-4), 7 leading candidates have emerged (5, 6). Four are portions of coding genes (matK, rbcL, rpoB, and rpoC1), and 3 are noncoding spacers (atpF-atpH, trnH-psbA, and psbK-psbI). Different research groups have proposed various combinations of these loci as their preferred plant barcodes, but no consensus has emerged (5-12). This lack of an agreed standard has impeded progress in plant barcoding.Our aim here is to identify a standard DNA barcode for land plants. To achieve this goal, we have pooled data across laboratories including sequence data from 907 samples, representing 445 angiosperm, 38 gymnosperm, and 67 cryptogam species. Using various subsets of these data, we evaluated the 7 candidate loci using criteria in the Consortium for the Barcode of Life's (CBOL) data standards and guidelines for locus selection (http:// www.barcoding.si.edu/protocols.html). Universality: Which loci can be routinely sequenced across the land plants? Sequence quality and coverage: Which loci are most amenable to the production of bidirectional sequences with few or no ambiguous base calls? Discrimination: Which loci enable most species to be distinguished? ResultsUniversality. Direct universality assessments using a single primer pair for each locus in angiosperms resulted in 90%-98% PCR and sequencing success for 6/7 regions. Success for the seventh region, psbK-psbI, was 77% (Fig. 1A). Greater problems were encountered in other land plant groups, with rpoB, matK, atpF-atpH, and psbK-psbI all showing Ͻ50% success in gymnosperms and/or cryptogams based on data compiled from several laboratories (Fig. 1 A).Sequence Quality. Evaluation of sequence quality and coverage from the candidate loci demonstrated that high quality bidirectional sequences were routinely obtained from rbcL, rpoC1, and rpoB (Fig. 1B, x axis). The remaining 4 loci required more manual editing and produced f...

Earlier research has revealed that the ndh loci have been pseudogenized, truncated, or deleted from most orchid plastomes sequenced to date, including in all available plastomes of the two most species-rich subfamilies, Orchidoideae and Epidendroideae. This study sought to resolve deeper-level phylogenetic relationships among major orchid groups and to refine the history of gene loss in the ndh loci across orchids. The complete plastomes of seven orchids, Oncidium sphacelatum (Epidendroideae), Masdevallia coccinea (Epidendroideae), Sobralia callosa (Epidendroideae), Sobralia aff. bouchei (Epidendroideae), Elleanthus sodiroi (Epidendroideae), Paphiopedilum armeniacum (Cypripedioideae), and Phragmipedium longifolium (Cypripedioideae) were sequenced and analyzed in conjunction with all other available orchid and monocot plastomes. Most ndh loci were found to be pseudogenized or lost in Oncidium, Paphiopedilum and Phragmipedium, but surprisingly, all ndh loci were found to retain full, intact reading frames in Sobralia, Elleanthus and Masdevallia. Character mapping suggests that the ndh genes were present in the common ancestor of orchids but have experienced independent, significant losses at least eight times across four subfamilies. In addition, ndhF gene loss was correlated with shifts in the position of the junction of the inverted repeat (IR) and small single-copy (SSC) regions. The Orchidaceae have unprecedented levels of homoplasy in ndh gene presence/absence, which may be correlated in part with the unusual life history of orchids. These results also suggest that ndhF plays a role in IR/SSC junction stability.

Many molecular studies have shown the monocot order Liliales to be well supported; morphologically, it is defined by synapomorphies of tepalar nectaries and extrorse anthers, in contrast with septal nectaries and introrse anthers commonly found in other monocots, especially Asparagales, with which it was often confused in the past. It comprises c. 1500 species, 67 genera and 9–11 families. Although monophyly is clear, the phylogenetic relationships among some of the families are still unclear. In this study, we examine the inter‐ and infrafamilial relationships among Liliales in phylogenetic analyses based on four plastid loci (matK, rbcL, atpB and atpF‐H). We performed phylogenetic analyses and constructed maximum parsimony and Bayesian trees for 49 genera and 148 taxa in ten families of Liliales sensu Angiosperm Phylogeny Group (APG) III using the combined DNA data. The monophyly of Liliales, except for Corsiaceae (Arachnitis), was strongly supported by both analyses. Campynemataceae were sister to the rest of the order, excluding Corsiaceae. The other families formed two well‐defined clades, (Colchicaceae + Alstroemeriaceae) and (Liliaceae, Smilacaceae, (Rhipogonaceae + Philesiaceae)), and one weakly supported clade with Melanthiaceae and Petermanniaceae. Subfamilial and tribal circumscriptions for the three larger families, Colchicaceae, Melanthiaceae and Liliaceae, agreed well with the results of this study, except for the subfamily Calochortoideae of Liliaceae, which was split into two separate clades of Calochortus and Tricyrtis. In addition, we found several taxa with a 10‐bp inversion in matK, which could contribute additional homoplasy to these analyses if included without re‐coding. Phylogenetic relationships among families of Liliales were better defined here than in a previous molecular analysis, although the placement of Corsiaceae with plastid data remains problematic. Based on these results, reconsideration of the circumscriptions of Rhipogonaceae + Philesiaceae and the subfamilial circumscription for Calochortoideae of Liliaceae is suggested. © 2013 The Linnean Society of London

The complete chloroplast genome of two colchicine medicinal plants is reported for the first time. Deletion of ycf 15 gene occurred only in Colchicum but not in Gloriosa and suggests this as a potential marker for delineating the two species. Colchicum autumnale L. and Gloriosa superba L. are well-known sources of colchicine, a type of alkaloid and an ancient anti-inflammatory drug used to prevent gout. Accordingly, this alkaloid has been used as a chemical marker for identifying the expanded Colchicaceae family. In the present study, we report the complete chloroplast genome (cpDNA) sequence of two colchicine medicinal plants (G. superba and C. autumnale) that belong to the tribe Colchiceae of the Colchicaceae family. In C. autumnale, the circular double-stranded cpDNA sequence of 156,462 bp consists of two inverted repeat (IR) regions of 27,741 bp each, a large single-copy region (LSC) of 84,246 bp, and a small single-copy region (SSC) of 16,734 bp. The cpDNA sequence of G. superba is longer than that of C. autumnale (157,924 bp), which consists of two IRs (28,063 bp), an SSC (16,786 bp), and an LSC (85,012 bp). Significant structural differences between them were observed in the ycf15 gene. ycf15 gene was absent from C. autumnale cpDNA and affected the length of the chloroplast genome between the species. Furthermore, this gene loss event was specific to the expanded genus of Colchicum sensu Vinnersten and Manning. Therefore, this gene may be an effective and powerful molecular marker for identifying the Colchicum genus within the family.

Monocots are one of the most diverse, successful and economically important clades of angiosperms. We attempt to analyse the complete plastid genome sequences of two lilies and their lengths were 152,793bp in Lilium longiflorum (Liliaceae) and 155,510bp in Alstroemeria aurea (Alstroemeriaceae). Phylogenetic analyses were performed for 28 taxa including major lineages of monocots using the sequences of 79 plastid genes for clarifying the phylogenetic relationship of the order Liliales. The sister relationship of Liliales and Asparagales-commelinids was improved with high resolution. Comparative analyses of inter-familial and inter-specific sequence variation were also carried out among three families of Liliaceae, Smilacaceae, and Alstroemeriaceae, and between two Lilium species of L . longflorum and L . superbum . Gene content and order were conserved in the order Liliales except infA loss in Smilax and Alstroemeria . IR boundaries were similar in IRa, however, IRb showed different extension patterns as JLB of Smilax and JSB in Alstroemeria . Ka/Ks ratio was high in matK among the pair-wise comparison of three families and the most variable genes were psaJ, ycf1, rpl32, rpl22, matK, and ccsA among the three families and rps15, rpoA, matK, and ndhF between Lilium.