Morphological and molecular characterisation of Pratylenchus rwandae n. sp. (Tylenchida: Pratylenchidae) associated with maize in Rwanda

Abstract

Summary Pratylenchus rwandae n. sp., a root-lesion nematode associated with maize (Zea mays) from Rwanda, is described. This new species is characterised by females of medium to large size (469-600 μm) having an offset lip region with three annuli, stylet of 13-14.6 μm long with prominent rounded or anteriorly concave knobs, short to long pharyngeal gland overlap of 10.9-34.7 μm long, variable number of lateral lines (4-14) in different regions of the body, lateral field consisting of smooth bands, oval to slightly rounded spermatheca, vulva located at 75-80% of the total body length, post-vulval uterine sac (PUS) 20.3-26.5 μm long, tail subcylindrical to conoid with variation in tail tip shape from rounded to truncate or indented with generally smooth tip, and male unknown. The results of the phylogenetic analyses based on sequences of the D2-D3 expansion regions of 28S, partial 18S and ITS of rDNA and COI of mitochondrial DNA indicate that P. rwandae n. sp. is a species within the Penetrans group and appears as a sister species to a group comprising P. convallariae, P. dunensis, P. fallax, P. oleae, P. penetrans, P. pinguicaudatus, and three other unidentified species. A comparison of important morphological characters of the closely related Pratylenchus spp. is provided.

Survey of slug-parasitic nematodes in East and West Flanders, Belgium and description ofAngiostoma gandavensisn. sp. (Nematoda: Angiostomidae) from arionid slugs

“…For the preparation of permanent slides, a small suspension of nematodes in an embryo dish were killed and fixed by adding a few drops of Trump's fixative (2% paraformaldehyde, 2.5% glutaraldehyde in 0.1M Sorenson buffer (Sodium phosphate buffer at pH 7.5)). The embryo dish was subsequently heated in a microwave (700 W) for 5 s, left to rest for 1 h at 20°C followed by 24 h at 4°C to ensure maximum penetration of the fixative, as described in Singh et al (2018). Following this, the nematodes were gradually transferred to anhydrous glycerin for permanent slides (Seinhorst, 1959) and mounted on glass slides for light microscopic study.…”

“…These vouchers were made with LM of temporary mount using photomicrographs. Vouchered nematodes were subsequently picked from temporary mounts, and each specimen was cut into pieces in distilled water and transferred to a polymerase chain reaction (PCR) tube with 20 μl of worm lysis buffer (50 mM KCl, 10 mM Tris at pH 8.3, 2.5 mM MgCl 2 , 0.45% NP 40 (Tergitol Sigma), 0.45% Tween 20) followed by incubation at −20°C (10 minutes), adding of 1 μl proteinase K (1.2 mg/ml), incubation at 65°C (1 h) and 95°C (10 minutes) and ending by centrifuging the mixture at 14,000 g for 1 minute (Singh et al, 2018). The primer pair D2A: 5 ′ -ACAAGTACCGTGAGGGAAAGTTG-3 ′ / D3B: 5 ′ -TCCTCGGAAGGAACCAGCTACTA-3 ′ (Nunn, 1992) was used to amplify D2D3 expansion segment of 28S rDNA following the thermal profile of 95°C for 4 minutes, 5× (95°C for 30 s, 58°C for 30 s, −1°C/cycle, ramp 3°C/s, 72°C for 2 minutes), 45× (95°C for 30 s, 54°C for 30 s, 72°C for 1 minute) and a final hold at 20°C.…”

A COI DNA barcoding survey of Pratylenchus species in the Great Plains Region of North America

“…Nematodes were extracted from 100 cm 3 field soil using a modified flotation-sieving and sugar centrifugation method (Jenkins, 1964) and from the host-root material using root incubation (Russell, 1987;Todd and Oakley, 1996). A majority of the samples recovered from Kansas was obtained from root extracts.…”

Short Communication: Updated tabular key and improved browser-based interactive key to species of Pratylenchus Filipjev (Nematoda: Pratylenchidae)

“…A total of thirteen species of Pratylenchus were added to the tabular key of Castillo and Vovlas (2007) that has been updated by Gafur (2014): P. musii (Geraert 2013;Eisvand et al 2019); P. gongjuensis (Choi et al 2006); P. kumamotoensis (Mizukubo et al 2007;Kim et al 2016); P. ispagoli and P. turmeri (Bairwa et al 2008); P. speijeri (De Luca et al 2012), P. oleae (Palomares-Rius et al 2014), P. quasitereoides (Hodda et al 2014), P. parazeae (Wang et al 2015;Wu et al 2019), P. haiduongensis (Nguyen et al 2017), P. rwandae (Singh et al 2018), P. horti (Nguyen et al 2019) and P. capsici (Qing et al 2019). Two morphotypes of P. bolivianus that have been detected (Troccoli et al 2016) were also incorporated in this update.…”