Morphological and molecular characterisation of Paralongidorus sacchari (Nematoda: Longidoridae), a new record of needle nematode in China

Abstract

A needle nematode of the genus Paralongidorus was isolated from Cuban royal palm (Roystonea regia) in China. Detailed morphological study confirmed that this species was the described needle nematode P. sacchari. Accordingly it was formally described and photographed. This nematode is characterised by a long body (4348–5825 μm), a board and anteriorly flat lip region slightly offset from body contour, bearing a stirrup-shaped amphidial fovea, with conspicuous slit-like aperture, a long and flexible odontostyle ca 101–110 μm long, stylet guiding ring located at 27.5–33.0 μm from anterior end, vulva near mid-body (48.0–50.0%), a short dorsally convex tail, with rounded terminus, and male absent. Molecular characterisation using near full-length 18S rRNA and D2-D3 expansion segments of 28S rRNA gene was also provided. Phylogenetic trees inferred from BI analysis of the two rRNA gene fragments revealed that P. sacchari could be distinguished from all described needle nematodes with molecular data, as well as the closely related species P. bikanerensis and P. sali. This nematode is a new record of Paralongidorus species from China. Cuban royal palm is a new host plant for P. sacchari.