First report of Scutellonema brachyurus (Steiner, 1938) Andrassy, 1958 and occurrence of Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949 in Belgium

A study of plant-parasitic nematodes in the Botanical garden at Ghent University in Belgium revealed the presence of two tropical nematode species, i.e. Scutellonema brachyurus and Meloidogyne incognita. Scutellonema brachyurus was recovered, only once, for the first time in Belgium from Musa basjoo and is morphologically characterized. M. incognita, forming galls on Hedychium greenii, was recovered in all seasons over three consecutive years and is morphologically and molecularly characterized. Although no unequivocal evidence was found to indicate that these nematodes pose a current threat in Belgium, in the light of climate change, it is crucial to improve our knowledge of potential tropical nematode activity in more Northern countries

Use of freeze-cracking in ontogenetic research in Macrostomum lignano (Macrostomida, Rhabditophora)

A method for studying whole mount flatworm embryos based on freeze-cracking of the eggs is described. This method allows successful immunohistological and immunocytological studies of whole mount embryos. It does not require the use of sharpened needles or a microinjection system to puncture the eggshell. Moreover, this method is more practical and less time-consuming than classical puncturing and much cheaper than the use of a microinjection system. The advantages of this method are illustrated by results of several immunolocalisation experiments in the macrostomid flatworm Macrostomum lignano. The optimal procedure and crucial steps for this method are discussed

Survey of slug-parasitic nematodes in East and West Flanders, Belgium and description of Angiostoma gandavensis n. sp. (Nematoda: Angiostomatidae) from arionid slugs

A survey for slug-associated nematodes in five locations of East and West Flanders in Belgium revealed the presence of one new and six known slug-parasitic nematodes, Agfa flexilis (Dujardin, 1845), Alloionema appendiculatum (Schneider, 1859), Angiostoma dentiferum (Mengert, 1953), Angiostoma limacis (Dujardin, 1845), Angiostoma norvegicum (Ross et al., 2017) and Phasmarhabditis hermaphrodita (Schneider, 1859). Angiostoma norvegicum and P. hermaphrodita are recorded for the first time in Belgium. The six known species are documented by light microscopy (LM) microphotographs and informative DNA sequences. Angiostoma gandavensis n. sp. (Angiostomatidae), discovered from arionid slugs, is described based on light microscopy, scanning electron microscopy (SEM) and molecular data. Based on analyses of D2D3 expansion segment of 28S and 18S rDNA sequences, this new species is found to be related to A. limacis, A. norvegicum, A. margaretae (Ross et al., 2011) and A. milacis (Ivanova and Wilson, 2009). The new species can be distinguished from these others based on morphological characters such as the distinctive mucronate structures at the tail tip of both sexes, presence of lateral ala, reflexed female ovaries and the number and arrangement pattern of male genital papillae

Plant-parasitic nematodes associated with sugarcane in Kilimanjaro, Tanzania

Morphological and molecular analyses of plant-parasitic nematodes (PPN) from 12 sugarcane plantation sites of Tanganyika Planting Company (TPC) Limited in Kilimanjaro region of Tanzania revealed the presence of six PPN genera, i.e. Helicotylenchus, Hemi-cycliophora, Pratylenchus, Rotylenchulus, Scutellonema, and Tylenchorhynchus. The genera with the highest densities and present in virtually all samples were Pratylenchus and Rotylenchulus, and the most important species appeared to be R. parvus, P. zeae, T. crassicaudatus, and T. ventrosignatus. A total sequences of 11 partial ITS, 15 D2-D3 of 28S, and 6 partial 18S of rRNA gene, and 7 partial COl gene of mtDNA of these species were obtained in this study. Morphology and molecular data comparisons between the Tanzanian R. parvus and the South African R. parvus indicated that R. parvus is a cryptic species complex. Based on the results of morphological and molecular analyses of T. crassicaudatus and T. agri from China, Haiti, Indonesia, Iran, Niger and the USA, T. agri syn. n. is proposed as a junior synonym of T. crassicaudatus

Integrative taxonomy and molecular phylogeny of the plant-parasitic nematode genus Paratylenchus (nematoda: paratylenchinae) : linking species with molecular barcodes

Pin nematodes of the genus Paratylenchus are obligate ectoparasites of a wide variety of plants that are distributed worldwide. In this study, individual morphologically vouchered nematode specimens of fourteen Paratylenchus species, including P. aculentus, P. elachistus, P. goodeyi, P. holdemani, P. idalimus, P. microdorus, P. nanus, P. neoamblycephalus, P. straeleni and P. veruculatus, are unequivocally linked to the D2-D3 of 28S, ITS, 18S rRNA and COI gene sequences. Combined with scanning electron microscopy and a molecular analysis of an additional nine known and thirteen unknown species originating from diverse geographic regions, a total of 92 D2-D3 of 28S, 41 ITS, 57 18S rRNA and 111 COI new gene sequences are presented. Paratylenchus elachistus, P. holdemani and P. neoamblycephalus are recorded for the first time in Belgium and P. idalimus for the first time in Europe. Paratylenchus is an excellent example of an incredibly diverse yet morphologically minimalistic plant-parasitic genus, and this study provides an integrated analysis of all available data, including coalescence-based molecular species delimitation, resulting in an updated Paratylenchus phylogeny and the corrective reassignment of 18 D2-D3 of 28S, 3 ITS, 3 18S rRNA and 25 COI gene sequences that were previously unidentified or incorrectly classified

Rotylenchus wimbii n. sp. (Nematoda: Hoplolaimidae) associated with finger millet in Kenya

Rotylenchus wimbii n. sp. was found associated with finger millet in Kenya and is described based on light microscopy, scanning electron microscopy, and molecular information. Sequence analysis was performed on ITS, 18S, and D2-D3 of 28S of ribosomal DNA and COI of mitochondrial DNA. This new species is characterized by a moderate female body size of 0.6 to 0.8 mm, a continuous hemispherical lip region with four annuli, 3 to 4 irregular blocks on the basal lip annule, absence of longitudinal cuticular striations in anterior region, four lateral lines forming three equal bands which are areolated mainly at pharynx level, a robust stylet of 23 to 27 pm of which 45 to 53% is cone part, and with rounded to sometimes indented knobs, a secretory-excretory pore around level of pharyngo-intestinal junction, didelphic-amphidelphic reproductive system, vulva without distinct epiptygma, indistinct to empty spermatheca, tail usually truncated with 5 to 9 annuli, phasmids located at 7 to 17 annuli anterior to anus, and absence of males. Molecular phylogenies, in combination with species delimitation, supported the distinctiveness of Rotylenchus wimbii n. sp. and revealed some mislabeled Rotylenchus brevicaudatus sequences in GenBank

The Caenorhabditis globin gene family reveals extensive nematode-specific radiation and diversification

<p>Abstract</p> <p>Background</p> <p>Globin isoforms with variant properties and functions have been found in the pseudocoel, body wall and cuticle of various nematode species and even in the eyespots of the insect-parasite <it>Mermis nigrescens</it>. In fact, much higher levels of complexity exist, as shown by recent whole genome analysis studies. <it>In silico </it>analysis of the genome of <it>Caenorhabditis elegans </it>revealed an unexpectedly high number of globin genes featuring a remarkable diversity in gene structure, amino acid sequence and expression profiles.</p> <p>Results</p> <p>In the present study we have analyzed whole genomic data from <it>C. briggsae</it>, <it>C. remanei</it>, <it>Pristionchus pacificus </it>and <it>Brugia malayi </it>and EST data from several other nematode species to study the evolutionary history of the nematode globin gene family. We find a high level of conservation of the <it>C. elegans </it>globin complement, with even distantly related nematodes harboring orthologs to many <it>Caenorhabditis </it>globins. Bayesian phylogenetic analysis resolves all nematode globins into two distinct globin classes. Analysis of the globin intron-exon structures suggests extensive loss of ancestral introns and gain of new positions in deep nematode ancestors, and mainly loss in the <it>Caenorhabditis </it>lineage. We also show that the <it>Caenorhabditis </it>globin genes are expressed in distinct, mostly non-overlapping, sets of cells and that they are all under strong purifying selection.</p> <p>Conclusion</p> <p>Our results enable reconstruction of the evolutionary history of the globin gene family in the nematode phylum. A duplication of an ancestral globin gene occurred before the divergence of the Platyhelminthes and the Nematoda and one of the duplicated genes radiated further in the nematode phylum before the split of the Spirurina and Rhabditina and was followed by further radiation in the lineage leading to <it>Caenorhabditis</it>. The resulting globin genes were subject to processes of subfunctionalization and diversification leading to cell-specific expression patterns. Strong purifying selection subsequently dampened further evolution and facilitated fixation of the duplicated genes in the genome.</p