Steinernema sacchari n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from South Africa

Nematology ◽  
2014 ◽  
Vol 16 (4) ◽  
pp. 475-494 ◽  
Author(s):  
Isaiah Nthenga ◽  
Rinus Knoetze ◽  
Shaun Berry ◽  
Louwrens R. Tiedt ◽  
Antoinette P. Malan

A new species of entomopathogenic nematode, Steinernema sacchari n. sp., was isolated by trapping with the sugar cane borer, Eldana saccharina, from soil of a sugar cane field in the KwaZulu-Natal province of South Africa. The new species is morphologically characterised by the length of the infective juvenile (IJ) of 680 (630-722) μm, tail length of 64 (51-74) μm, ratio a = 19 (14-23), H% = 49 (43-57) and E% = 82 (70-109). The pattern of the lateral field of the IJ of the new species is 2, 5, 2 ridges (3, 6, 3 lines or incisures). The male of the first generation can be recognised by the long spicule of 83 (73-89) μm, gubernaculum of 61 (50-68) μm, D% = 67 (54-88) and GS% = 73 (66-81). The first generation male lacks a mucron, while the second generation male always has one. The first generation female can be recognised by the vulval lips not being raised, the possession of long double-flapped epiptygmata and the lack of a postanal swelling. Analysis of the ITS and D2D3 regions showed S. sacchari n. sp. to differ from all other Steinernema species and to belong to a new monophyletic group, the ‘Cameroonian’ clade, consisting of S. cameroonense, S. nyetense and S. sacchari n. sp. This group is closely related to the feltiae-kraussei-oregonense Clade III.

Nematology ◽  
2016 ◽  
Vol 18 (2) ◽  
pp. 235-255 ◽  
Author(s):  
Birhan A. Abate ◽  
Antoinette P. Malan ◽  
Louwrens R. Tiedt ◽  
Michael J. Wingfield ◽  
Bernard Slippers ◽  
...  

A new species of entomopathogenic nematode, Steinernema fabii n. sp., was isolated by trapping with wax moth (Galleria mellonella) larvae from soil in an Acacia mearnsii plantation in the Mpumalanga province of South Africa. The new species is morphologically characterised by the length of the infective juvenile (IJ) of 641 (590-697) μm, by a tail length of 58 (52-64) μm, ratio a = 24 (21-41), H% = 53 (37-61) and E% = 93 (83-105). The pattern of the lateral field of the IJ of the new species is 2, 5, 2 ridges (3, 6, 3 incisures). The male of the first generation can be recognised by the long spicule of 90 (79-106) μm and gubernaculum of 66 (56-77) μm; D% = 64 (52-75) and GS% = 73 (63-86). The first generation female can be recognised by a protruding vulva with a short, double-flapped epiptygmata, and the lack of a postanal swelling, while the second generation differs in having a postanal swelling and a conical, sharply pointed tail. Analysis of DNA sequences for the ITS and D2-D3 gene regions showed S. fabii n. sp. to differ from all other Steinernema species and to belong to a new monophyletic group, the ‘Cameroonian’ clade, consisting of S. cameroonense, S. nyetense, S. sacchari and S. fabii n. sp., all from the African continent. This group is closely related to species in the feltiae-kraussei-oregonense Clade III.


Nematology ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 343-360 ◽  
Author(s):  
Agil Katumanyane ◽  
Antoinette P. Malan ◽  
Louwrens R. Tiedt ◽  
Brett P. Hurley

Summary Two isolates of Steinernema bertusi n. sp. were separately recovered from Tito, Mpumalanga, and Port Edward, Kwa Zulu Natal, South Africa. In this paper, we describe the isolates as a new entomopathogenic nematode (EPN) species using molecular and morphological methodologies. The new species belongs to the cameroonense-clade, which consists of nematodes only isolated from the African continent. Steinernema bertusi n. sp. is characterised by having the longest infective juvenile (IJ) for this clade at 716 (628-814) μm. The IJ is further characterised by a body diam. of 32 (28-36) μm and the pattern for the arrangement of the lateral ridges from head to tail is 2, 4, 5, 4, 2. The first-generation male spicule and gubernaculum length is 82 (72-88) μm and 63 (54-72) μm, respectively. Only 25% of the second-generation males possess a mucron. The first-generation females of S. bertusi n. sp. have a slightly protruding vulva, with double-flapped epiptygmata and a mucron at the posterior end. The new EPN species is most closely related to S. sacchari and is the sixth species to be included in the cameroonense-clade.


Nematology ◽  
2016 ◽  
Vol 18 (5) ◽  
pp. 571-590 ◽  
Author(s):  
Antoinette P. Malan ◽  
Rinus Knoetze ◽  
Louwrens R. Tiedt

Steinernema nguyenin. sp. was recovered by baiting from beneath anOlea africanatree in South Africa. The combination of morphological and molecular features suggests thatS. nguyenin. sp. is a member of thefeltiae-kraussei-oregonensegroup, clustering with members of this group in Clade III. The new species is morphologically characterised by the infective juvenile body length of 737 (673-796) μm and the number of ridges in the infective juvenile lateral field is 2, 8, 2. The male of the first generation can be recognised by the spicule length of 66 (58-75) μm and a gubernaculum length of 43 (30-55) μm. The first generation female can be recognised by the vulval lips only slightly protruding and the presence of low, double-flapped epiptygmata. Analysis of the ITS and D2-D3 regions of the ribosomal DNA confirms thatS. nguyenin. sp. differs from all other knownSteinernemaspecies.


Nematology ◽  
2006 ◽  
Vol 8 (2) ◽  
pp. 157-175 ◽  
Author(s):  
Antoinette Malan ◽  
Ugur Gozel ◽  
Khuong Nguyen

AbstractA new species of entomopathogenic nematode, Steinernema khoisanae n. sp. is described from South Africa. The new species is characterised by morphometrics of the infective juvenile with body length 1076 μm, narrow body diameter of 33 μm, excretory pore 94 μm from anterior end, tail 85 μm long, a = 33, D% = 68, H% = 57, and E% = 111. The lateral field pattern of the new species is 2, 7, 8, 6, 4 and 2. The male of the first generation can be recognised by the spicule and the gubernaculum shape, excretory pore located posteriorly near the end of the pharynx, D% = 88, and SW% = 199. The first generation female can be recognised by the non-protruding vulva and tail bearing a prominent mucron. Steinernema khoisanae n. sp. is characterised genetically by sequences of the internal transcribed spacers and D2/D3 regions of 28S ribosomal DNA, by composition of their sequences and by numerous unique, derived, nucleotide character states. Phylogenetic trees show that S. khoisanae n. sp. and other members of the S. glaseri-group form a monophyletic assemblage.


Nematology ◽  
2004 ◽  
Vol 6 (6) ◽  
pp. 819-838 ◽  
Author(s):  
Mutsuhiro Yoshida

AbstractA new entomopathogenic nematode, Steinernema litorale n. sp., was isolated from sandy soils in Cape Irago, Atsumi Peninsula, Aichi, Honshu Island, Japan. The new species is characterised by the following morphological characters: infective third-stage juvenile with a body length of 909 ± 42.1 (834–988) μm, distance from head to excretory pore of 61 ± 3.3 (54–69) μm, tail length of 83 ± 4.5 (72–91) μm, ratio E value of 0.73 (0.68–0.83) and lateral field with nine distinct lines; male tail with a mucron in both generations, spicule shape (moderately arcuate, heavy, spicule with elongated manubrium), spicule length of 75 ± 4.8 (67–89) μm and gubernaculum length of 53 ± 4.0 (44–64) μm in the first generation male; female vulva with a double-flapped epiptygma and a tail with a pointed tip in both generations, and ratio D value of 45.2 (33.3–56.8) in the first generation female. The new species was distinguished from the morphologically similar species, S. feltiae, S. thanhi, S. karii, S. scarabaei, S. kraussei, S. oregonense, S. loci and S. diaprepesi by RFLP profiles. Morphological and molecular studies indicated that S. litorale n. sp. was phenotypically most similar to S. feltiae. However, cross hybridisation tests demonstrated that the two species were reproductively isolated.


Nematology ◽  
2012 ◽  
Vol 14 (6) ◽  
pp. 723-739 ◽  
Author(s):  
Juan Ma ◽  
Juan Ma ◽  
Shulong Chen ◽  
Juan Ma ◽  
Shulong Chen ◽  
...  

During a survey for entomopathogenic nematodes in northern China, a new species of Steinernema was isolated from soil samples collected from Xinbin county, Liaoning province. This nematode was obtained by the insect-baiting technique using last instar larvae of Galleria mellonella. It is described herein as S. xinbinense n. sp. The nematode can be separated from other described species of the group by morphological and morphometric characteristics of the different stages and by characterisation and phylogeny of DNA sequences of the D2D3 domain of the LSU or ITS regions of rDNA. This new species is characterised by the following morphological characters: infective third-stage juvenile with a body length of 694 (635-744) μm, distance from head to excretory pore of 51 (46-53) μm, tail length of 73 (61-81) μm, E = 71 (65-78)%, presence of eight unevenly spaced and developed ridges in middle lateral field (i.e., nine lines). First generation male with well curved, yellowish spicules 56 (49-62) μm long and gubernaculum 35 (30-41) μm long, small mucron mostly present, first generation female with protruding vulva, tail conical with one or two small mucrons and D = 45 (41-50)%. Cross hybridisation tests with S. tielingense, S. kraussei, S. feltiae and S. hebeiense showed that this species was reproductively isolated. The analyses of ITS-rDNA and D2D3 sequence confirm that the studied nematode isolate is a valid new species belonging to the ‘feltiae-kraussei-oregonense’ group.


Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 569-587 ◽  
Author(s):  
Nomakholwa F. Stokwe ◽  
Antoinette P. Malan ◽  
Khuong B. Nguyen ◽  
Rinus Knoetze ◽  
Louwrens Tiedt

Abstract During a survey for entomopathogenic nematodes in citrus orchards throughout South Africa, a new species of Steinernema was isolated from a citrus orchard on Rietkloof farm, near the town of Piketberg in the Western Cape Province, South Africa. The nematode was isolated from soil using the Galleria-baiting technique. Steinernema citrae n. sp. is characterised by the following morphological characters: third-stage infective juvenile with a body length of 754 (623-849) μm, distance from head to excretory pore of 56 (49-64) μm, tail length of 71 (63-81) μm, and ratio E value of 110 (85-132). The lateral pattern for the new species is 2, 7, 8, 6, 4, 2 and is not typical for the genus. Steinernema citrae n. sp. is closely related the feltiae-group. The body length of the IJ is close to that of S. texanum and S. weiseri, though it differs in body diam., the length of the pharynx and E%. The male of S. citrae n. sp. differs from S. feltiae in the length and shape of the spicule and body diam. Steinernema citrae n. sp. differs from all species in the feltiae-group in the morphology of the vulva, as it has a single flapped, low, epiptygma. It also differs from the most closely related species, S. feltiae, as there is no interbreeding between the two species. In addition, the new nematode differs from other species of the feltiae-group by characteristics of the ITS and D2D3 regions of its rDNA.


Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 401-412 ◽  
Author(s):  
S. Patricia Stock ◽  
Christine T. Griffin ◽  
Rani Chaerani

Abstract Steinernema hermaphroditum n. sp., a new entomopathogenic nematode isolated from soil samples in the Moluccan islands, Indonesia, is described. Morphological observations as well as biological evidence (cross-hybridisation studies) indicate the distinctness of S. hermaphroditum n. sp. from other Steinernema spp. This new species is characterised by the presence of hermaphrodites in the first adult generation. Key morphological diagnostic characters include: a digitate tail with a mucro and a glandular spermatheca filled with sperm in the first generation hermaphrodite; the value of D%; the morphology of the male spicules and gubernaculum and the number and arrangement of the genital papillae; the values of D%, E% and the pattern of the lateral field of the third-stage infective juvenile. Additionally, molecular evidence obtained from ITS rDNA RFLP profiles, 28S rDNA sequence analyses, and phylogenetic reconstruction provide further evidence to establish this nematode as a new species.


Nematology ◽  
2006 ◽  
Vol 8 (5) ◽  
pp. 681-690 ◽  
Author(s):  
Long K. Phan ◽  
Shuhei Takemoto ◽  
Kazuyoshi Futai

Abstract Steinernema ashiuense sp. n. was collected by a Galleria baiting method from grassland along the riverbank of the Yura river, near the Ashiu Research Forest Station of Kyoto University. The new species is characterised by an infective juvenile body length of 768 (720-800) μm, lateral field with five equally developed ridges (i.e., six lines or incisures), head smooth lacking horn-like structures, excretory pore located at level of middle of pharynx, hyaline portion short (ca one-third of tail length). Males have 50-65 μm long, broad, slightly yellowish spicules; spicule length / spicule width = 4 (3.5-4.4), and two subventral and one subdorsal pair of genital papillae in the postcloacal region. The analysis of ITS-rDNA sequence placed S. ashiuense sp. n. in the 'feltiae-kraussei-oregonense' group in the clade containing S. robustispiculum and S. monticolum. It can be distinguished from these species by morphological characters of the infective juveniles and males.


Nematology ◽  
2014 ◽  
Vol 16 (7) ◽  
pp. 761-775 ◽  
Author(s):  
Ke Long Phan ◽  
Zdeněk Mráček ◽  
Vladimír Půža ◽  
Jiří Nermut ◽  
Andrea Jarošová

A new entomopathogenic nematode, Steinernema huense sp. n., belonging to the carpocapsae group, was recovered in Bach Ma National Park (Thua Thien Hue province) Vietnam. Steinernema huense sp. n. infective juveniles are characterised by short body length of 527 (444-571) μm, distance from anterior end to excretory pore of 43 (38-46) μm, anterior end to end of pharynx of 116 (103-129) μm; tail length of 50 (43-56) μm, D% = 37 (34-39) and E% = 85 (79-93), H% = 44 (39-52) and in having six ridges (i.e., seven lines) in the lateral field. For first generation males, the diagnostic characters include the spicule length of 67 (60-72) μm; D% = 48 (41-61); SW% = 195 (168-238) and GS% = 76 (68-81). Both generations possess a minute filamentous mucron, which can be rudimentary in the first generation, and 23 genital papillae. Spicules are finely curved, brownish and slender with a prominent rostrum. First generation females have a non-protruding, symmetrical vulva, with double flapped epiptygma. The tail of mature females is obese with a short conical tip (peg) lacking minute protuberances, and post-anal swelling not developed. The new species is further characterised by sequences of ITS and D2-D3 regions of the ribosomal DNA. According to molecular data, the symbiotic bacterium of S. huense sp. n. is closely related to Xenorhabdus stockiae.


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