Description of Gracilacus paralatescens n. sp. (Nematoda:Paratylenchinae) found from the rhizosphere of Bamboo in Zhejiang, China

Abstract

Gracilacus paralatescens n. sp., isolated in Anji County, Zhejiang Province, China from the rhizospheric soil of bamboo. The new species can be characterized by the female lateral field with three incisures, stylet 71.5 to 78.8 µm long, lip region truncated, excretory pore located anterior to basal knobs. Vulval lips non-protruding and without vulval flap, spermatheca large, elongated squarish shaped filled with sperms. Tail slender, relatively straight having wedge shape terminus. The spicule slender, slightly curved and 17.5 to 18.9 µm long. In the phylogenetic analysis based on 18S, D2-D3 of 28S and ITS regions of rDNA, the new species is clustered with Paratylenchid species having longer stylet length. Morphologically, the new species belongs to Group 9 of Paratylenchus sensu lato and is most similar to G. latescens.

Integrative Taxonomy and Molecular Phylogeny of the Plant-Parasitic Nematode Genus Paratylenchus (Nematoda: Paratylenchinae): Linking Species with Molecular Barcodes

“…The genus Paratylenchus sensu lato , with 124 valid species, is an important plant-parasitic group consisting of several commonly occurring and economically important species such as P. bukowinensis, P. dianthus, P. hamatus, P. nanus, P. neoamblycephalus and P. projectus , which are difficult to separate solely based on morphology [ 14 , 23 , 25 , 31 , 32 , 33 , 34 , 35 , 36 ]. Female morphological traits are the most commonly used features for the identification of Paratylenchus populations, with the relative lengths of stylet cones and the positions of the secretory-excretory pores and vulvae as the most informative traits [ 31 , 67 ], while several ratios such as a, c and c’ show high intraspecific variation.…”

“…The nominal species were pragmatically divided into eleven groups based on stylet length, number of lateral lines and absence vs. presence of vulval flaps in females. Since then, seven more species of Paratylenchus have been described and linked to DNA sequences [ 14 , 25 , 32 , 33 , 34 , 35 , 36 ]. Molecular work on this nematode group is gaining momentum and provides an attractive solution to difficulties encountered in species identification, as well as phylogenetic relationships among species.…”

“…by using 58 28S rRNA and 40 ITS rRNA gene sequences. Several other studies provided additional molecular characterisations, phylogenetic analyses and descriptions of new Paratylenchus species [ 14 , 25 , 32 , 33 , 34 , 35 , 36 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. In a study by Hesar et al [ 24 ], 28S rRNA and ITS rRNA gene sequences of several Paratylenchus spp.…”

Updated description of Paratylenchus lepidus Raski 1975 and P. minor Sharma, Sharma and Khan, 1986 by integrating molecular and ultra-structural observations

“…The host range of pin nematodes in China is quite diverse. The paratylenchid species have been documented from plants, shrubs and trees (Chen et al, 2002;Fang et al, 2012;Wang et al, 2016;Maria et al, 2018a). Out of 31 reported species, only P. alleni (Ras-ki, 1975a); P. bukowinensis (Micoletzky, 1922); P. epacris (Allen and Jensen, 1950); P. minutus (Linford et al, 1949); P. nanjingensis (Wang et al, 2014), and G. steineri (Golden, 1961) were documented from Pinus massoniana, P. sylvestris and P. thunbergii (Chen et al, 2002;Fang et al, 2012).…”

“…The species of pin nematodes are commonly distributed in China, more than 30 species have been reported from 21 provinces (Maria et al, 2018a). The host range varies from horticultural to agronomic crops as well as ornamental and forestry plants (Raski, 1991).…”