Molecular characterization and phylogenetic position of Rotylenchus pini Mamiya, 1968 (Nematoda: Hoplolaimidae) from Korea, with remarks on its morphology and morphometrics

Rotylenchus pini Mamiya, 1968 was reported from rhizospheric soils of Zoysia japonica in Korea. Females and males are morphologically characterized and their linked DNA barcodes (18S-rRNA, 28S-rRNA and COI) supplied. Females and males of the characterized population conform to the original species description from Japan and also to other subsequent species descriptions with variations in a few details in morphometrics including the existence of pharyngeal gland overlap in some specimen. Bayesian phylogenetic analysis of all the three DNA markers consistently grouped R. pini together with Rotylenchus species including R. zhongshanensis, a morphologically close species. Additionally, the newly obtained sequences of R. pini were found to be almost identical to the sequences assigned to Rotylenchus aff. devonensis in GenBank. These Rotylenchus aff. devonensis isolates might be representatives of R. pini populations. Polyphasic taxonomy has a potential to adequately infer clarity on morphological and molecular relationships within this genus. The current and previous phylogenetic studies supported by the recorded morphological plasticity within populations of the genus validate the proposed synonymy of Pararotylenchus with Rotylenchus. This is the first molecular characterization of R. pini. Additional molecular studies of the member species of the genus especially those with bulb-shaped pharyngeal glands are needed to aid reconstruction of phylogenetic patterns within the group. This will supplement the current generic compendia.