Phylogenetic position of Discolaimium (Nematoda: Dorylaimida) from South Africa using 28S rDNA

Abstract

 Dorylaim nematodes inhabit soil and are predatory, primarily feeding on other nematodes. This predatory behaviour positions them as a potential natural solution to combat plant-parasitic nematodes. By preying on their fellow nematodes, they contribute significantly to ecological diversity. Therefore, this molecular study was conducted in 2022 at the University of Limpopo to identify the soil nematodes from South Africa using a 28S rDNA marker. The recovered nematode was extracted using the tray method. The Chelex method was used to extract DNA, and the nematode was identified as Discolaimium. Afterward, 28S rDNA was amplified using specific primers to identify the nematode. The Nblast analysis based on the small subunit ribosomal DNA showed that South African Discolaimium has a 97% similarity (MG921263) with the Chinese population of Discolaimium. Phylogenetic analysis using maximum likelihood placed this species with those molecularly identified as Discolaimium in the same clade with highly supported (100) bootstrap values. In conclusion, this species was properly identified using 28S rDNA. However, other DNA markers are recommended to understand the Discolaimium phylogeny better.