TY - JOUR
T1 - The pitfalls of molecular species identification: a case study within the genus Pratylenchus (Nematoda: Pratylenchidae)
JF - Nematology
Y1 - 2017
DO - 10.1163/15685411-00003117
A1 - Janssen, Toon
A1 - Karssen, Gerrit
A1 - Couvreur, Marjolein
A1 - Waeyenberge, Lieven
A1 - Bert, Wim
SP - 1–21
KW - acrobeloides cf
KW - barcoding provide a
KW - DIAGNOSTICS
KW - for
KW - identification of organisms and
KW - mislabelled sequences
KW - MOLECULAR PHYLOGENY
KW - molecular taxonomy and dna
KW - nanus
KW - new synonym
KW - powerful tool for the
KW - pratylenchus flakkensis
KW - pratylenchus goodeyi
KW - pratylenchus lentis n
KW - pratylenchus pratensis
KW - syn
KW - topotypes
VL - 00
SN - 1568541100003
UR - http://booksandjournals.brillonline.com/content/journals/10.1163/15685411-00003117
ER -
TY - BOOK
T1 - Integrative taxonomy of root-knot nematodes reveals multiple independent origins of mitotic parthenogenesis
T2 - PLoS ONE
Y1 - 2017
DO - 10.1371/journal.pone.0172190
A1 - Janssen, Toon
A1 - Karssen, Gerrit
A1 - Topalović, Olivera
A1 - Coyne, Danny
A1 - Bert, Wim
SP - e0172190
AB - During sampling of several Coffea arabica plantations in Tanzania severe root galling, caused by a root-knot nematode was observed. From pure cultures, morphology and mor-phometrics of juveniles and females matched perfectly with Meloidogyne africana, whereas morphology of the males matched identically with those of Meloidogyne decalineata. Based on their Cox1 sequence, however, the recovered juveniles, females and males were con-firmed to belong to the same species, creating a taxonomic conundrum. Adding further to this puzzle, re-examination of M. oteifae type material showed insufficient morphological evi-dence to maintain its status as a separate species. Consequently, M. decalineata and M. otei-fae are synonymized with M. africana, which is herewith redescribed based on results of light and scanning electron microscopy, ribosomal and mitochondrial DNA sequences, isozyme electrophoresis, along with bionomic and cytogenetic features. Multi-gene phylogenetic analy-sis placed M. africana outside of the three major clades, together with M. coffeicola, M. ichino-hei and M. camelliae. This phylogenetic position was confirmed by several morphological features, including cellular structure of the spermatheca, egg mass position, perineal pattern and head shape. Moreover, M. africana was found to be a polyphagous species, demonstrat-ing that " early-branching " Meloidogyne spp. are not as oligophagous as had previously been assumed. Cytogenetic information indicates M. africana (2n = 21) and M. ardenensis (2n = 51–54) to be a triploid mitotic parthenogenetic species, revealing at least four independent ori-gins of mitotic parthenogenesis within the genus Meloidogyne. Furthermore, M. mali (n = 12) was found to reproduce by amphimixis, indicating that amphimictic species with a limited num-ber of chromosomes are widespread in the genus, potentially reflecting the ancestral state of the genus. The wide variation in chromosome numbers and associated changes in reproduc-tion modes indicate that cytogenetic evolution played a crucial role in the speciation of root-knot nematodes and plant-parasitic nematodes in general.
JF - PLoS ONE
VL - 12
SN - 1111111111
ER -
TY - JOUR
T1 - An early record of Meloidogyne fallax from Ireland
JF - ZooKeys
Y1 - 2017
DO - 10.3897/zookeys.643.11266
A1 - Topalović, Olivera
A1 - Moore, John F.
A1 - Janssen, Toon
A1 - Bert, Wim
A1 - Karssen, Gerrit
SP - 33–52
KW - CHARACTERS
KW - Cork
KW - Host
KW - morphology
KW - Morphometrics
KW - Root-knot nematode
AB - Root-knot nematodes, Meloidogyne spp., cause huge economic losses worldwide. Currently, three Meloidogyne spp. are present on the quarantine A2 list of EPPO, M. chitwoodi, M. fallax and M. enterolobii. As a quarantine organism, M. fallax has been detected in England and Northern Ireland on sport turf in 2011, and in England on leek in 2013. However, its presence in Ireland has probably been overlooked since 1965, when Mr. John F. Moore and Dr. Mary T. Franklin had detected a new Meloidogyne species for that time. While the relevant data was recorded and a preliminary manuscript describing the species was prepared but never submitted for publication, and together with the original slides, pictures and drawings, it was restudied recently. We compared the population of Irish Meloidogyne sp. to other similar Meloidogyne spp. Careful observation and comparison shows that it belongs to M. fallax. The characters found to be common for Irish Meloidogyne sp. and M. fallax are female stylet length (14.6 μm) with oval to rounded basal knobs, oval shaped perineal pattern with moderately high dorsal arch, slender stylet in males (18.5 μm) with set off and rounded basal knobs, slightly set off male head with one post-labial annule and incomplete transverse incisures, and second-stage juveniles with large and rounded stylet basal knobs, and a gradually tapering tail (46.9 μm) with a broadly rounded tip and a clearly delimitated smooth hyaline part sometimes marked by constrictions (12.9 μm). The host test and gall formation also correspond to M. fallax. The identification could not be additionally supported by molecular analysis, as we were unable to extract DNA from the old permanent slides. Nevertheless, our study reveals that the Meloidogyne species detected in Ireland in 1965 belongs to M. fallax.
VL - 2017
ER -
TY - JOUR
T1 - Molecular characterization and species delimiting of plant-parasitic nematodes of the genus Pratylenchus from the penetrans group (Nematoda: Pratylenchidae)
JF - Molecular Phylogenetics and Evolution
Y1 - 2017
DO - 10.1016/j.ympev.2017.07.027
A1 - Janssen, Toon
A1 - Karssen, Gerrit
A1 - Orlando, Valeria
A1 - Subbotin, Sergei A.
A1 - Bert, Wim
KW - Cryptic species complex
KW - DNA Barcoding
KW - phylogeny
KW - Pratylenchus arlingtoni
KW - Root-lesion nematodes
KW - species delimitation
AB - Root-lesion nematodes of the genus Pratylenchus are an important pest parasitizing a wide range of vascular plants including several economically important crops. However, morphological diagnosis of the more than 100 species is problematic due to the low number of diagnostic features, high morphological plasticity and incomplete taxonomic descriptions. In order to employ barcoding based diagnostics, a link between morphology and species specific sequences has to be established. In this study, we reconstructed a multi-gene phylogeny of the Penetrans group using nuclear ribosomal and mitochondrial gene sequences. A combination of this phylogenetic framework with molecular species delineation analysis, population genetics, morphometric information and sequences from type location material allowed us to establish the species boundaries within the Penetrans group and as such clarify long-standing controversies about the taxonomic status of P. penetrans, P. fallax and P. convallariae. Our study also reveals a remarkable amount of cryptic biodiversity within the genus Pratylenchus confirming that identification on morphology alone can be inconclusive in this taxonomically confusing genus.
UR - http://dx.doi.org/10.1016/j.ympev.2017.07.027
ER -
TY - JOUR
T1 - mtCOI successfully diagnoses the four main plant-parasitic Aphelenchoides species (Nematoda: Aphelenchoididae) and supports a multiple origin of plant-parasitism in this paraphyletic genus
JF - European Journal of Plant Pathology
Y1 - 2017
DO - 10.1007/s10658-016-1141-1
A1 - Sanchez-Monge, Alcides
A1 - Janssen, Toon
A1 - Fang, Yiwu
A1 - Couvreur, Marjolein
A1 - Karssen, Gerrit
A1 - Bert, Wim
KW - Concatenated analysis
KW - Foliar nematodes
KW - Molecular b
PB - European Journal of Plant Pathology
UR - http://link.springer.com/10.1007/s10658-016-1141-1
ER -
TY - JOUR
T1 - Description of Malenchus sexlineatus n. sp., new records of three known species of Malenchus andrassy, 1968 (Nematoda: Tylenchidae) and notes on amphidial aperture development
JF - NematologyNematology
Y1 - 2016
A1 - Qing, Xue
A1 - Sanchez-Monge, Alcides
A1 - Janssen, Toon
A1 - Couvreur, Marjolein
A1 - Bert, Wim
SP - 155
EP - 174
AB - A new species, Malenchus sexlineatus n. sp., discovered from the Philippines, is described based on morphological and molecular data. The new species is unusual in the genus by having six lateral lines. Malenchus sexlineatus n. sp. is distinguished from M. williamsi, the only other species in the genus with six lateral lines (based on currently available SEM data), by a shorter body of 278 (270-288) vs 452 (425-495) mu m, shorter stylet (7.0 (6.2-7.5) vs 11-12 mu m), narrower annulations (0.8 (0.7-0.8) vs 1.2-1.6 mu m), lateral field comprising one elevated ridge in LM vs six well-separated incisures (resembling the lateral lines in Cephalenchus) in LM, the presence of S-shaped vs straight amphidial apertures, and vulval flaps absent or only one annuli long vs distinct. By having an exceptionally short body, M. sexlineatus n. sp. comes close to M. parvus, M. bryanti and M. acarayensis. However, there are significant differences in the lateral lines, annuli width and most morphometric ratios. Three known species, namely M. exiguus, M. nanellus and M. pachycephalus, all being first records and first representative from China, are characterised by morphological data. The new species was placed in a robustly supported clade containing two other Malenchus spp. and M. exiguus. Interestingly, M. pressulus was placed in a separate, unresolved phylogenetic position. However, the phylogenetic position of these clades could not be resolved within Tylenchidae. The shapes of the amphidial aperture and fovea within Malenchus are also compared and its possible developmental process is illustrated and discussed.
VL - 18
SN - 1388-5545
N1 - Times Cited: 02
ER -
TY - JOUR
T1 - Molecular phylogeny of Kalyptorhynchia (Rhabdocoela, Platyhelminthes) inferred from ribosomal sequence data
JF - Zoologica ScriptaZoologica Scripta
Y1 - 2014
A1 - Tessens, Bart
A1 - Janssen, Toon
A1 - Artois, Tom
SP - 519
EP - 530
VL - 43
SN - 0300-3256
N1 - Times Cited: 0
ER -
TY - JOUR
T1 - Two new species of Carcharodorhynchus Meixner, 1938 (Platyhelminthes: Rhabdocoela: Schizorhynchidae) from Brazil and Lanzarote
JF - Marine BiodiversityMarine Biodiversity
Y1 - 2014
A1 - Reygel, Patrick
A1 - Schockaert, Ernest
A1 - Janssen, Toon
A1 - Artois, Tom
SP - 279
EP - 285
VL - 44
SN - 1867-1616
N1 - Times Cited: 22
ER -