| Paratylenchus Micoletzky, 1922 is the largest genus of the family Paratylenchidae Raski, 1962, and it contains more than 100 species. More than 20 known species have been reported in China. The nematodes of Paratylenchus have a broad host range. High densities of Paratylenchus have been detected in association with cultivated plants, fruit trees, forest trees and grasses. Some species of Paratylenchus have been considered as the pathogens of their hosts. Hemicaloosia Ray & Das, 1978 is belong to the family Caloosiidae Siddiqi, 1980 in the superfamily Hemicycliophoroidea Skarbilovich, 1959, and there are 9 valid species in this genus. There have been no reports on Hemicaloosia in China. In this study, soil and root samples have been collected from many province in China. In total, 16 Paratylenchus species and one Hemicaloosia species have been detected. There are 4 new species and 6 new record species to China in the 16 Paratylenchus species. In addition, a new disease of anthurium was detected in this study. The main results are shown as follows:1. A new species named Paratylenchus chongqingensis n. sp. was found in association with Ophiopogon japonicus in Chongqing. The morphological characterization is as follows: female body length is 262(243–274.5) μm, female stylet length is 23(21–24.5) μm, there are three lines in the lateral field, female head is set off and a little disk-shaped, lateral vulval flaps is prominent, tail tip is finely rounded; male head is slight rounded, stylet is absent and oesophagus is degenerate, penial sheath is short, tail tip is short filiform. Three ITS sequences of P. chongqingensis n. sp. were amplified in this study. The length of the three ITS sequences was 990 bp with 2–6 bp variation.2. A new species named Paratylenchus guangzhouensis n. sp. was detected in association with Bambusa multiplex in Guangzhou, Guangdong. The morphological characterization is as follows: female body length is 233(217–247) μm, female stylet length is 47(43–49.5)μm, lateral field with three lines, female head is rounded and not set off, amphid opening is bow-tie like in shape, lateral vulval flaps is small, tail tip is finely rounded to bluntly rounded; male head is rounded, stylet is absent, oesophagus is degenerate, penial sheath is short, and tail tip is subacute; fourth-stage juvenile have a stylet. There are two ITS sequences and three 28 S r DNA D2-D3 sequences of this new Paratylenchus species obtained in this study. The length of the two ITS sequences was 1034 bp and 1035 bp with 1 bp variation. The length of the three D2-D3 sequences was 771 bp with 0 bp variation.3. A new species named Paratylenchus nanjingensis n. sp. was detected in association with Pinus massoniana in Nanjing, Jiangsu. The morphological characterization is as follows: female body length is 259(243–279) μm, female stylet length is 66(64–68) μm, there are four lines in the lateral field, female head is not set off with submedian lobes, excretory pore is located anterior to the level of stylet knobs, lateral vulval flaps is small but distict, tail tip is finely rounded or subacute; male head is conical-truncate, stylet is absent and oesophagus is degenerate, penial sheath is short, tail tip is subacute. Three sequences of the ITS region and two sequences of the 28 S r DNA D2-D3 region of P. nanjingensis n. sp. were obtained in this study. The length of the three ITS sequences was 1032 bp with 0–2 bp variation. The length of the two D2-D3 sequences was 771 bp with 0 bp variation.4. High densities of pin nematode was observed in association with anthurium in Shenzhen, Guangdong. Morphological and molecular studies revealed that it is a new species of Paratylenchus and was named Paratylenchus shenzhenensis n. sp. The morphological characterization is as follows: female body length is 275(249–302) μm, female stylet length is 19(17–21) μm, lateral field with four lines, female head is rounded, not set off, having four submedian lobes, lateral lobes is smaller, a little depression at the oral area, having distinct lateral vulval flaps, female tail terminus is narrowly rounded or sub-digitate; male body curved ventrally from the anterior end to the region of the cloaca and then curved dorsally behind the cloacal opening, stylet is absent and oesophagus is degenerate, penial sheath is prominent; juveniles have stylets. Sixteen ITS sequences and nine sequences of the 28 S r DNA D2-D3 region of P. shenzhenensis n. sp. were also obtained in this study. The length of these ITS sequences was 1047–1049 bp with 0–33 bp variation. Intraspecific variation of the sequences from the D2-D3 regionfor P. shenzhenensis n. sp. was 0–6 bp. Anthurium infected by P. shenzhenensis n. sp. were stunted, roots presented brown, dark brown or black rot. A method of culturing the new species on carrot disks was established, and the optimum temperature for culturing this nematode is 25°C. P. shenzhenensis n. sp. were inoculated to anthurium roots and the pathogenicity of the nematode was tested according to Koch’s postulates.5. Six new record species of Paratylenchus in China were found in this study. They are P. costatus, P. discocephalus, P. longicaudatus, P. serricaudatus, P. variabilis and P. variatus. We conclude that P. anchorus and P. costatus may be synonyms of P. idalimus, P. epicotylus may be synonyms of P. discocephalus, and both P. variatus and P. aquaticus shoule be valid species.6. A new Hemicaloosia species named Hemicaloosia guangzhouensis n. sp. was collected from Guangzhou, Guangdong. The morphological characterization is as follows: female body length is 906(798–961) μm, total number of annuli is 298(282–313), female stylet length is 65.5(59–69) μm, entire body was covered by a membranous sheath, lateral field has one longitudinal line, there is no sperm in the spermatheca, tail length is 130(115–145) μm, the number of annulus from vulva to tail terminus is 63(58–69), the number of annulus from anus to tail terminus is 53(49–59), the number of annulus from vulva to anus is 9(7–11), and the male is not found. The two newly obtained ITS sequences of H. guangzhouensis n. sp. were 805 bp in length with 0 bp variation. Two 769-bp D2-D3 regions of the 28 S r DNA sequences of H. guangzhouensis n. sp was obtained, and variation of the two D2-D3 sequences was 1 bp. Two 882-bp 18 S r DNA sequences of the new species were obtained, and variation of the two 18 S sequences was 1 bp. The PCR-ITS-RFLP diagnostic profile generated by six restriction enzymes for the new species is given in this study. Lengths of restriction fragments from RFLP for the ITS r DNA were: Ava I-805 bp(not restricted); Bsh1236I-805 bp(not restricted); Dra I-805 bp(not restricted); Hinf I-625, 132, 48 bp; Hin6I-586, 130, 78, 11 bp; Msp I-424, 303, 78 bp.7. Phylogenetic trees of the Paratylenchus species were reconstructed based on the ITS data set and D2-D3 data set in this study. |
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