First molecular characterization of the small subunit ribosomal RNA gene of Hysterothylacium fabri larvae (Nematoda: Raphidascarididae) from Mediterranean Sea

Hysterothylacium fabri is commonly reported in various Mediterranean fish. However, there is no data on the mitochondrial ribosomal RNA (rrnS) gene sequence of H. fabri larvae in the Mediterranean Sea waters. Therefore, we aimed to reveal molecular characterization of H. fabri based on the rrnS gene sequence in the current study. Firstly, the fourth stage of H. fabri larvae were identified at parasitological examination from Mullus barbatus in the Mediterranean Sea. Morphologically identified H. fabri larvae herein were also supported by the sequencing of the nuclear ribosomal ITS gene regions. In the next step, the rrnS gene of these larvae was molecularly analysed. Our H. fabri isolate (MK886659) showed 96.42% identity with H. fabri reported from China (MF140349) based on the rrnS gene. The nucleotide difference based on the rrnS gene between Chinese isolate (MF140349) and our H. fabri isolate (MK886659) was determined as 3.2%. Consequently, for the first time, the mitochondrial rrnS gene sequencing of H. fabri from the Mediterranean waters were performed in the current study.