Diversity analysis of southern African Artemisia afra using a single nucleotide polymorphism derived from diversity arrays

Abstract

Artemisia afra is an aromatic shrub used as a herbal remedy in southern Africa for various disorders, including coughs, colds, influenza, and, most notably, for the prophylaxis and treatment of Plasmodium falciparum infections. Modern high-throughput genotyping by sequencing, which combines next generation sequencing and diversity array technology (DArTseq) complexity reduction methods, allows for the generation of high-quality whole-genome profiles without any previous organismal genetic information that may hamper the diversity analyses. This study investigated the feasibility of incorporating DArTseq-derived single-nucleotide polymorphisms (SNPs) and bioactive compounds into a geographic information system to predict the spatial distribution of A. afra gene diversity in selected southern African environs. DNA extraction, sequencing, and SNP calling mineral analyses (using R Studio) were performed on a total of 80 genotypes collected around Roma and Mohale’s Hoek, Lesotho, and Wepener and Hobhouse, South Africa. The unweighted pair group method with arithmetic mean (UPGMA) and neighbour-joining dendrograms revealed three clusters of variation among genotypes; however, geographic distribution did not influence A. afra genetic diversity. The mean heterozygosity among genotypes was 7.7%. Genotypes collected in Roma and Mohale’s Hoek exhibited high levels of genetic diversity. Local A. afra genetic diversity was relatively low, indicating uniformity of subspecies per locality. The diversity among genotypes indicated that A. afra SNPs may occur despite the location. Given that genetic diversity enhances crop performance, our findings can be useful in germplasm management, industries producing by-products of A. afra, and plant breeding programs. For the long-term conservation of medicinal plants in South Africa, significant sampling and regional data are required. In addition to evaluating qualitative and quantitative assessments of phytochemicals, it is necessary to evaluate foliar mineral composition, as well as the agronomic and morphological characteristics of collected specimens from studied locations.