Aphelenchus yinyuensis n. sp. (Tylenchina: Aphelenchoididae) found in Terminalia sp. in China.

Gu Jianfeng,Liu Lele,Xianfeng Chen,Bo Cai,Munawar Maria,Yiwu Fang

doi:10.21307/jofnem-2020-085

Gu Jianfeng, Liu Lele + Show 4 more

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https://doi.org/10.21307/jofnem-2020-085

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Abstract

During a nematode biodiversity survey in Hainan Province, China, Aphelenchus yinyuensis n. sp. was detected in the rhizosphere of Terminalia sp. It is characterized by medium-sized a body of adult nematodes, i.e. 793 (639-877) μm and 756 (647-863) μm for females and males, respectively, with low, rounded, not offset lip region. The lateral field has 10 incisures. The excretory pore is located posterior to the nerve ring. The vagina is not sclerotised and the vulva has simple lips without a flap. The PUS is well developed and forms ca 45 to 83% of the vulva to anus distance. Female tail is straight, cylindrical, ca 2.7 times longer than anal body diam, tail tip broad, and bluntly rounded. Males have four pairs of caudal papillae and spicule 28.7 (25.8-32.3) μm long in the chord and well developed bursa, extending to the tail tip. 18S and 28S rRNA phylogenetic analyses were performed for the new species, and the ITS analysis was not performed due to low posterior probability support. Phylogenetically, the new species grouped with Aphelenchus avenae and this is the first new Aphelenchus species ever described from China.

Highlights

The Aphelenchoidea (Fuchs, 1937; Thorne, 1949) is a large group of stylet bearing nematodes that have adapted to a wide range of ecological relationships including phytoparasitism, predation, fungus feeding, association with insects in soil and obligate insect parasitism (Nickle, 1970)
The genus contains 11 nominal species (Hunt, 2008), only A. avenae attracted the economic value because it is a non-parasitic, fungivores nematode commonly found in croplands of all over the world and has been tested as a biological agent to control soil-borne plant pathogens (Azimi, 2018; Haraguchi and Yoshiga, 2020)
In an attempt to investigate the nematode biodiversity in Hainan Province, a population of Aphelenchus nematode was detected from Terminalia sp. in Sansha City in an unbalanced adult ratio, i.e. more males than females

Summary

Introduction

The Aphelenchoidea (Fuchs, 1937; Thorne, 1949) is a large group of stylet bearing nematodes that have adapted to a wide range of ecological relationships including phytoparasitism, predation, fungus feeding, association with insects in soil and obligate insect parasitism (Nickle, 1970). Species of genus Aphelenchus (Bastian, 1865) mostly occur in soil, leaf sheaths, plant crowns, and cortex of some roots where they presumably feed on fungal hyphae. The genus contains 11 nominal species (Hunt, 2008), only A. avenae attracted the economic value because it is a non-parasitic, fungivores nematode commonly found in croplands of all over the world and has been tested as a biological agent to control soil-borne plant pathogens (Azimi, 2018; Haraguchi and Yoshiga, 2020). The unbalanced adult ratio is not common in Aphelenchus species, the research has demonstrated that under unfavorable conditions the Pine Wood Nematode can regulate its population by changing sex ratios (Cui et al, 2018). Our results confirmed that this population has unique characters and belonged to a new species; it is describe as Aphelenchus yinyuensis n. sp

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