High-throughput sequencing of African chikanda cake highlights conservation challenges in orchids

• Published in: Biodiversity and conservation Vol. 26; no. 9; pp. 2029 - 2046
• Main Authors: Veldman, Sarina, Gravendeel, Barbara, Otieno, Joseph N., Lammers, Youri, Duijm, Elza, Nieman, Aline, Bytebier, Benny, Ngugi, Grace, Martos, Florent, van Andel, Tinde R., de Boer, Hugo J.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-08-2017; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Biodiversity; Biomedical and Life Sciences; Cakes; CITES; CITES (Convention on International Trade in Endangered Species); Climate Change/Climate Change Impacts; Commercialization; Conservation; Conservation biology; Conservation Biology/Ecology; Conserved sequence; Desserts; Detection; Disa; Documentation; Ecology; Ethnobotany; Flowers & plants; Food; Food processing; Genera; Habenaria; Identification; Ingredients; Ion-Torrent PGM; Life Sciences; Matching; Matematikk og Naturvitenskap: 400; Mathematics and natural science: 400; Next-generation sequencing; Nucleotide sequence; Original Paper; Populations; Processed foods; Products; Satyrium; Sequencing; Similarity; Species diversity; Sustainability; Tubers; VDP; Wildlife forensics; Zoologiske og botaniske fag: 480; Zoology and botany: 480; Ion-Torrent PGM; Ethnobotany; Wildlife forensics; CITES
• ISSN: 0960-3115; 1572-9710; 1572-9710
• DOI: 10.1007/s10531-017-1343-7

Chikanda
is a traditional dish made with wild-harvested ground orchid tubers belonging to three orchidioid genera,
Disa
,
Satyrium
and
Habenaria
, all of which are CITES appendix II-listed. Identification of collected orchid tubers is very difficult and documentation of constituent species in prepared
chikanda
has hitherto been impossible. Here amplicon metabarcoding was used in samples of six prepared
chikanda
cakes to study genetic sequence diversity and species diversity in this product. Molecular operational taxonomic unit identification using similarity-matching reveals that species of all three genera were present in the
chikanda
samples studied.
Disa
was present in all of the samples,
Satyrium
in five out of six and
Habenaria
in one of the samples, as well as a number of other plants. The fact that each sample contained orchids and the presence of a wide variety of species from all genera in this traditional dish raise serious concerns about the sustainability of this trade and the future of wild orchid populations in the main harvest areas. This proof-of-concept study shows that Ion-Torrent PGM is a cost-effective scalable platform for metabarcoding using the relatively long nrITS1 and nrITS2 regions. Furthermore, nrITS metabarcoding can be successfully used for the detection of specific ingredients in a highly-processed food product at genus level, and this makes it a useful tool in the detection of possible conservation issues arising from commercialized trade or processed plant products.