Heterodera guangdongensis Zhuo & Wang & Zhang & Liao 2014, n. sp.

Heterodera guangdongensis n. sp. Figs. 1–3 = Heterodera sp. GD 1 in Zhuo et al. 2013 Measurements. See Table 2. Material examined. Type-material: Holotype cyst, three paratype vulval cones, one paratype male and five paratype J2s are deposited in the USDA Nematode Collection, Beltsville, Maryland; three paratype vulval cones, one paratype male and five paratype J2s in the Canadian National Nematode Collection, Ottawa, Canada. Other specimens are available in the Laboratory of Plant Nematology, South China Agricultural University, Guangzhou, China. Description. Cyst. Lemon-shaped with distinct neck and vulval cone, light brown to dark brown in color. Stylet and other internal structures indistinct. Cuticle with irregular zig-zag pattern, but without remnant subcrystalline layer. Vulval cone ambifenestrate. Underbridge weak. Bullae absent. Eggs packed in the body. Anus distinct. ......continued on the next page White female. Body lemon-shaped, white in color, with prominent neck and vulval cone. Subcrystalline layer present. Head set off, with two annuli, the second annule larger and disc-shaped. Stylet long, with rounded knobs sloping slightly posteriorly. Dorsal pharyngeal gland duct opens 3–4 µm behind the basal knobs. Median bulb massive, with strongly developed valve plates. Excretory pore indistinct. Egg sac sometimes present, ranging from one-half to two times the size of the female, containing eggs. Male. Body vermiform, slightly curved ventrally when heat-relaxed. Lateral field with four incisures, outer bands areolated, wider than central band. Annulus width at mid-body about 1.8 µm. Head hemispherical, slightly offset, with a distinct labial disc and four or five postlabial distinct annuli. Stylet developed, with knobs slightly projecting or flat anteriorly. Dorsal pharyngeal gland duct opens 4–6 µm behind the basal knobs. Median bulb oval, with strong valve plates. Nerve ring slightly posterior to median bulb. Excretory pore 108–152.5 µm from anterior end of the body. Hemizonid 112–140 µm from anterior end of the body. Spicules arcuate, with finely bifurcate tip. Gubernaculum straight and simple. Tail very short and bluntly rounded. Phasmids indistinct. J2. Body vermiform, slightly ventrally curved when heat-relaxed. Lateral field with three incisures. Body annuli 1.5–1.7 µm at mid-body. Head offset, hemispherical, with a labial disc and three or four indistinct postlabial annuli. Stylet robust with knobs slightly projecting or flat anteriorly. Dorsal pharyngeal gland duct opens 5.8–7 µm behind the basal knobs. Median bulb ovoid and prominent. Pharyngeal glands well developed. Hemizonid situated slightly anterior to excretory pore. Genital primordium oval, 8.0 (7.7–8.3) µm long, 5.8 (5.7–6.0) µm wide, 129.8 (100.7–143.7) µm anterior to tail terminus. Anus distinct. Tail conoid, narrowly tapering to a fine rounded terminus, hyaline terminal section distinct, 24.6 (18.3–33.8) µm long, occupying 50.1 (43.0–57.1)% of tail length. Phasmids pore-like, 5–8 annuli posterior to anus. Diagnosis and relationships. Heterodera guangdongensis n. sp. belongs to the Cyperi group of Subbotin et al. (2010a). Cysts are characterized by a protruding, ambifenestrate vulval cone with small fenestrae (22.0– 33.8 µm in length), weak underbridge, short vulva-anus distance (28.9–35.9 µm) and a 31.1–41.0 µm long vulval slit, but without bullae; females are characterized by a 25.1–27.6 µm long stylet with rounded knobs sloping slightly posteriorly; males are characterized by a 21.5–23.0 µm long stylet with knobs slightly projecting or flat anteriorly, four incisures in lateral field, a 22.0–26.0 µm long spicule with bifurcate tip; J2s are characterized by a 19.3–21.3 long stylet with slightly projecting or anteriorly flattened knobs, three incisures in lateral field, a 41.7–61.3 µm long tail with finely rounded terminus and hyaline portion forming 50.1 (43.0–57.1)% of the tail length. In its morphology, the new species is most closely related to four members of the H. cardiolata Kirjanova & Ivanova, 1969 complex in the Cyperi group, including H. cardiolata, H. graminis Stynes, 1971, H. phragmitidis Kazachenko, 1986 and H. longicolla Golden & Dickerson, 1973. The new species differs from H. cardiolata by the more oblate fenestrae (22–33.8 µm vs 44–70 µm in length), the shorter vulva-anus distance (28.9–35.9 µm vs 42–50 µm), the longer female stylet (25.1–27.6 µm vs 19–21.4 µm) and the J2 stylet knob shape (slightly projecting or anteriorly flattened vs prominently anteriorly directed). It differs from H. graminis by the longer female stylet (25.1–27.6 µm vs 19–24 µm), the smaller female DGO (3–4 µm vs 5–7 µm), the more oblate fenestrae (22.0– 33.8 µm vs 32–63 µm in length), the shorter vulva-anus distance (28.9–35.9 µm vs 40–50 µm), the J2 stylet knob shape (slightly projecting or anteriorly flattened vs prominent anteriorly concave), the male stylet knob shape (slightly projecting or flat anteriorly vs rounded) and the shorter spicules (22–26 µm vs 31–35 µm). From H. phragmitidis, it differs by the longer female stylet (25.1–27.6 µm vs 19.5–21 µm), the smaller female (223.6–398.5 × 207.9–367.9 µm vs 467–812 × 394–677 µm), the smaller cyst (266.5–415.1 × 207–361.2 µm vs 407–836 × 318.2–738 µm), the shorter spicules (22–26 µm vs 28.6–41.6 µm), the shorter gubernaculum (7.8–8 µm vs 11.7–14.3 µm), the male stylet knob shape (slightly projecting or flat anteriorly vs rounded) and the larger J2 DGO (5.8–7 µm vs 3.6–4.8 µm). It can be distinguished from H. longicolla by the longer female stylet (25.1–27.6 µm vs 19–21 µm), the more oblate fenestrae (22.0– 33.8 µm vs 37 µm in length), the longer male stylet (21.5–23 µm vs 17.9–20.2 µm), more incisures in the male lateral field (4 vs 3), more head annuli in the male (4–5 vs 3), the slightly shorter spicules (22–26 µm vs 25.2–28.6 µm), the shorter gubernaculum (7.8–8 µm vs 9–10.6 µm), the longer J2 stylet (19.3–21.3 µm vs 16.8–18.5 µm) and the larger J2 DGO (5.8–7 µm vs 3.4–6.1 µm). The new species is also similar to other members of the Cyperi group, including H. cyperi Golden, Rau & Cobb, 1962, H. elachista Ohshima, 1974 and H. oryzicola Rao & Jayaprakash, 1978. It can be distinguished from H. cyperi by the longer female stylet (25.1–27.6 µm vs 22–22.4 µm), the smaller female DGO (3–4 µm vs 4.5–5.6 µm), the shorter female (223.6–398.5 µm vs 459–663 µm), the shorter cyst (266.5–415.1 µm vs 459–742 µm), the shorter males (624.0– 861.3 µm vs 874–1159 µm), the shorter spicules (22–26 µm vs 28–30.8 µm), the shorter gubernaculum (7.8–8 µm vs 8–10 µm), the male stylet knob shape (slightly projecting or flat anteriorly vs rounded), the shorter J2 (318.1–409.5 µm vs 414–532 µm), the slightly larger J2 DGO (5.8–7 µm vs 3.8–6.1 µm) and the slightly shorter J2 tail (41.7–61.3 µm vs 56–79 µm); from H. elachista by the longer female stylet (25.1–27.6 µm vs 19–23 µm), the absence of bullae (vs presence), the absence of subcrystalline in cyst stage (vs presence), the longer male stylet (21.5–23 µm vs 20–21 µm), the shorter spicules (22–26 µm vs 26–29 µm), the shorter gubernaculum (7.8–8 µm vs 8–13 µm) and the male stylet knob shape (slightly projecting or flat anteriorly vs sloping posteriorly); from H. oryzicola by the shorter female (223.6–398.5 µm vs 414–520 µm), the longer female stylet (25.1–27.6 µm vs 18–20 µm), the absence of bullae (vs presence), the shorter males (624–861.3 µm vs 896–980 µm) and the J2 stylet knob shape (slightly projecting or anteriorly flattened vs rounded). Compared with the four Heterodera species from bamboo, i.e. H. bamboosi, H. koreana, H. hainanensis and H. fengi, H. guangdongensis n. sp. can be easily distinguished from the first three species by the presence of fenestrae (vs afenestrate). In addition, the new species further differs from H. bamboosi by the presence of a prominent vulval cone (vs absence of vulval cone) and more incisures in the male lateral field (4 vs 3); from H. koreana and H. hainanensis by more J2 lip annuli (3–4 vs 2). H. guangdongensis n. sp. differs from H. fengi by the longer female stylet (25.1–27.6 µm vs 23–24 µm), the smaller fenestrae (22.0–33.8 × 27.8–35.5 µm vs 40–65 × 45–62.5µm), the shorter vulval slit (31.1–41 µm vs 40–60 µm), the shorter male stylet (21.5–23 µm vs 24.5–26.3 µm), the male stylet knob shape (slightly projecting or flat anteriorly vs rounded, sloping posteriorly), the shorter spicules (22–26 µm vs 27.5–31.3 µm), the shorter J2 (318.1–409.5 µm vs 440–520 µm), the shorter J2 stylet (19.3–21.3 µm vs 22–24 µm), the larger J2 DGO (5.8–7 µm vs 4.5–5.3 µm), the shorter J2 tail (41.7–61.3 µm vs 62.5–77 µm) and the shorter J2 hyaline tail portion (18.3–33.8 µm vs 35–45 µm). Type-locality and habitat: Heterodera guangdongensis n. sp. was originally collected from roots and soils around roots of bamboo (Phyllostachys pubescens) in Guangzhou City (latitude N23°9'23'', longitude E113°21'40''), Guangdong Province, China in 2009. The soil type is sandy loam and the local climate is subtropical. Other locality: Other than the type locality, H. guangdongensis n. sp. was also collected from roots and soils around roots of P. pubescens in Nanning City (latitude N22°52'44'', longitude E108°25'3'') and Hechi City (latitude N24°33'29'', longitude E107°46'30''), Guangxi Province, China in 2011. The soil type is sandy loam and the local climate is also subtropical. Etymology: The specific name refers to the type locality, Guangdong Province. Molecular profiles and phylogenetic status. Three rDNA amplicons of 784-bp LSU D2D3 were sequenced, obtained from single J2s collected from Guangzhou, Hechi and Nanning, respectively. GenBank accession numbers of the three sequences are JX081320, KM224882 and JX081321. The identities among these three D2D3 sequences of H. guangdongensis n. sp. were 99.6–99.7%. A BlastN search of H. guangdongensis n. sp. on the LSU D2D3 showed high-scoring matches with some Heterodera species, the highest being with two s

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.