Molecular characters of free-living nematode Panagrolaimus (Nematoda: Rhabditida) using 28S rDNA from South Africa

Bacterivorous nematodes are a type of nematodes that live in the soil. Free-living bacterivores are crucial for the soil food web, biological control, and ecological studies. Within the free-living bacterivorous nematodes, Panagrolaimus is a species that feeds on pathogenic bacteria, making it important in the transmission of plant-pathogenic bacteria. Additionally, Panagrolaimus plays a role in the nitrification of minerals in the soil. In 2023, a molecular study was conducted at the University of Limpopo to identify bacterivorous nematodes in South Africa's soils using the 28S rDNA marker. The nematode was extracted using the tray method, and its DNA was extracted using the Chelex method. It was then identified as Panagrolaimus. To further identify the nematode, 18S rDNA was amplified using specific primers. The Nblast analysis based on the small subunit ribosomal DNA showed that South African Panagrolaimus has a 95% similarity (EU543176) with the Belgian population. Based on a phylogenetic analysis using maximum likelihood, this species has been placed within the same clade as other species identified as Panagrolaimus, with highly supported (100) bootstrap values. Therefore, this species has been properly identified using 18S rDNA. However, to gain a better understanding of the phylogeny of Panagrolaimus, it is recommended to use other DNA markers as well.