Phylogenetic position of Diploscapter coronatus (Nematoda: Rhabditida) using 28S rDNA from South Africa

Abstract

Free-living bacterivores nematodes are the main nematodes that live in the soil. Free-living bacteria are essential for the soil food web. The genus Diploscapter is distributed in the soil with several species. Hence, the identification based on the molecular rDNA, specifically 28S rDNA is necessary for D. coronatus. Therefore, this molecular study was conducted in 2018 at the Limpopo University to identify the freeliving bacterivores nematodes from South Africa's soils using 28S rDNA marker. The recovered nematode was extracted using the tray method, and then its DNA was extracted using chelex method. Afterward, 28S rDNA was amplified using specific primers to identify the nematode. The Nblast analysis based on the large subunit ribosomal DNA showed South African D. coronatus has 97% similarity (MK541668) with Germany's population. Phylogenetic analysis using maximum likelihood placed this species with those molecularly identified as D. coronatus in the same clade with highly supported (100) bootstrap values. In conclusion, this species is identified using 28S rDNA properly. However, using other rDNA markers such as 18S rDNA and ITS rDNA for a better understanding of Diploscapter phylogeny is recommended.