Testing DNA barcoding in closely related groups of Lysimachia L. (Myrsinaceae)

Abstract

It has been suggested that rbcL and matK are the core barcodes in plants, but they are not powerful enough to distinguish between closely related plant groups. Additional barcodes need to be evaluated to improve the level of discrimination between plant species. Because of their well-studied taxonomy and extreme diversity, we used Chinese Lysimachia (Myrsinaceae) species to test the performance of core barcodes (rbcL and matK) and two additional candidate barcodes (trnH-psbA and the nuclear ribosomal ITS); 97 accessions from four subgenus representing 34 putative Lysimachia species were included in this study. And many closely related species pairs in subgen. Lysimachia were covered to detect their discriminatory power. The inefficiency of rbcL and matK alone or combined in closely related plant groups was validated in this study. TrnH-psbA combined with rbcL + matK did not yet perform well in Lysimachia groups. In contrast, ITS, alone or combined with rbcL and/or matK, revealed high resolving ability in Lysimachia. We support ITS as a supplementary barcode on the basis of core barcode rbcL and matK. Besides, this study also illustrates several mistakes or underlying evolutionary events in Lysimachia detected by DNA barcoding.

Utility of DNA barcoding to identify rare endemic vascular plant species in Trinidad

“…The chloroplast ribulose‐1, 5‐bisphosphate carboxylase/oxygenase large subunit gene ( rbcL ) and maturase K gene ( matK ) are the approved barcodes for land plants (CBOL Plant Working Group 2009). However, plant‐plastid barcodes typically have lower resolving power to separate closely related plant species compared to the animal barcode, and in several cases, conspecifics or recently diverged species do not form highly supported, distinct sequence clusters that allow species discrimination (Hollingsworth et al., 2016; van Velzen, Weitschek, Felici, & Bakker, 2012; Zhang et al., 2012). In fact, a uniquely identified species in a given genus is the exception rather than the rule in most plant barcoding studies (Hollingsworth, Graham, & Little, 2011).…”

DNA barcoding of plants: Selection of core markers for taxonomic groups

“…The plastid markers such as rbcL and matK exhibited low resolution in species-rich genera and complex taxa such as Lysimachia, Ficus, Holcoglossum, and Curcuma (7-10). The lowest discriminatory power was observed in closely related groups of Lysimachia with rbcL (26.5-38.1%), followed by matK (55.9-60.8%) and combinations of core barcodes (rbcL + matK) had discrimination of 47.1-60.8% (10). Mangroves identification based on core DNA barcode exhibited rbcL 47.72%, matK locus assigned (72.09%), ITS2 (87.82%) and combinations of matK + ITS2 resolved (89.74%) species however Avicennia species required additional atpF-atpH marker (34)(35).…”

DNA barcodes successfully identified Macaronesian Lotus (Leguminosae) species within early diverged lineages of Cape Verde and mainland Africa

“…Panamanian trees with 98 % of species identification (Kress et al 2009) and Mesoamerican orchids with >90 % of species identification (Lahaye et al 2008), but the success of species discrimination tends to decrease as the number of species within families or genera is increased (Gonzalez et al 2009; Xiang et al 2011; Yesson et al 2011; Zhang et al 2011; Arca et al 2012; Maia et al 2012; Saarela et al 2013). Previous studies have reported relatively low (55 % using trnH-psbA in Aspalathus ) to moderately high percentages (e.g.…”