Study on × Bolboschoenoplectus mariqueter and its related species based on DNA barcoding

Abstract

The taxonomic status of × Bolboschoenoplectus mariqueter (Tang & F. T. Wang) Tatanov is still up for debate. To clarify this status and explore its genetic relationship with closely related species, the candidate DNA barcode sequences of one nuclear gene (ITS) and five chloroplast genes (matK, ndhF, rbcL, trnL and trnL-trnF) were used for PCR amplification and sequencing of 21 individuals from four species, including × Bolboschoenoplectus mariqueter and its related species. The basic local alignment search tool was then applied to evaluate the identification efficiency of the screened barcode sequences and sequence combinations. Finally, species identification analyses were performed by constructing a phylogenetic tree using the Bayesian inference method. The results were as follows: (1) The ITS + matK sequence combination showed the highest species-resolving degree of 71.4%, which could achieve interspecific differentiation and identification of × Bolboschoenoplectus mariqueter and its closely related species. (2) According to the phylogenetic tree based on ITS + matK sequence combination, samples of the same species showed better aggregation and were mostly monophyletic, with × Bolboschoenoplectus mariqueter clustered together with all Bolboschoenus (Asch.) Palla individuals, rather than Schoenoplectus (Rchb.) Palla species. All × Bolboschoenoplectus mariqueter and Bolboschoenus maritimus (Linnaeus) Palla samples formed a monophyletic clade. In conclusion, ITS + matK sequence combination appears to be the best barcode sequence for interspecific identification of × Bolboschoenoplectus mariqueter and its related species. Furthermore, × Bolboschoenoplectus mariqueter could be a synonym of Bolboschoenus maritimus rather than a natural hybrid. This study establishes a theoretical foundation for the taxonomic research on × Bolboschoenoplectus mariqueter and its closely related species.

Keywords

• × bolboschoenoplectus mariqueter
• related species
• dna barcoding
• species identification
• genetic relationship