Abstract Detail

Floristics & Taxonomy

Song, Feng [1], Feng, Ying [1], Ge, Xue-Jun [2].

Plastid super-barcodes as a tool for species discrimination in Calligonum (Polygonaceae).

Calligonum (Polygonaceae) is a genus with about 80 species distributed from southern Europe through northern Africa to western central Asia, typically found in arid and desert areas. They are xerophytic branched shrubs or subshrubs. The highly variable fruit morphology character was used during the species identification, which caused the confusing in species delimitation. The previous study verified the failure of DNA barcoding in discriminating Calligonum species. In this study, we sequenced 25 complete plastid genomes representing 23 recognized species of Calligonum. Our purpose is to verify whether complete plastome as super-barcode could provide sufficient variation to identify Calligonum species effectively, and to find specific barcode locus for species discrimination in this genus. The analysis revealed genome organization, gene number, gene order, and GC content of these 25 plastome genomes are highly similar. The plastome genomes range in size from 161,184 to 162,465 bp, and with a typical quadripartite structure. There are 113 genes, including 79 protein-coding genes, 30 tRNA genes, 4 rRNA genes. The complete plastid genomes revealed much higher species identification (12/23) than core DNA barcode combination (rbcL + matK, 2/23; rbcL + matK + trnL-F, 4/23). We also found that psbE-petL and trnT-trnL two spacers are hotspots in plastome. Both spacers provided the highest successfully identified number of taxa (21/23). Among the 79 coding regions, rpoC2 gene is the most variable, which identified 13 of the 23 species. This study suggested that complete plastome sequence as a super-barcode for Calligonum is more reliable and effective than core DNA barcode. However, not all species can be fully identified. This may be related to the frequent introgression or hybridization occurred between species in this genus.

1 - Xinjiang Institute of Ecology and Geography, Herbarium, 40 Beijing South Road, Urumqi, Xinjiang, CHINA
2 - South China Botanical Garden, Chinese Academy Of Sciences, 723 Xingke Rd., Tianhe District, Guangzhou, 510650, China

Keywords:
Calligonum
plastome
super-barcode.

Presentation Type: Poster
Session: P, Floristics and Taxonomy
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PFT002
Abstract ID:176
Candidate for Awards:None