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During a nematode survey in Iran, an abundant population of sheathoid, migratory, root-ectoparasitic nematodes was recovered from a tea, Camellia sinensis (L.), Kuntze plantation for the first time. Morphological and molecular characterization identified the Iranian population as Hemicriconemoides kanayaensis. The morphometrics of H. kanayaensis agreed with the original description. Phylogenetic relationships within Hemicriconemoides—based on ITS region, D2 to D3 expansion regions of the 28S rRNA, and the partial 18S rRNA genes along with the partial mitochondrial COI gene—confirmed the occurrence of H. kanayaensis on the tea plantation in Iran. Principal component analysis (PCA) confirmed the high intraspecific and interspecific variabilities among Hemicriconemoides species and between H. kanayaensis populations.

Publications between 2000 and 2024 on plant pathogenic species of Helicotylenchus nematodes were reviewed using bibliometric analyses with VOSviewer software. Sequences in GenBank for the same period were used to reconstruct phylogenetic relationships and correctly assign all the Helicotylenchus sequences in the database. The Scopus database was selected for its professional standards, international visibility, broad coverage, and controlled-vocabulary thesaurus available for indexing and retrieving documents. GenBank collects nucleotide sequences and relevant bibliographic and biological annotations for sequence analyses. This study highlighted research trends and specific complexities of working with Helicotylenchus, and the suitability of molecular markers used for identification of the main pathogenic species and confirmation of occurrence of species complexes or cryptic species. [ABSTRACT FROM AUTHOR]

Rotylenchus arasbaranensis n. sp., a new monosexual species is described and illustrated based on morphological, morphometric and molecular studies. The new species is characterised by having an offset and hemispherical lip region with 5-6 annuli, 32-36 μm long stylet, vulva located at 43.9-59.2% with a single epiptygma and rounded tail, rarely bilobed, with 6-8 annuli. The species R. striaticeps and the male of R. buxophilus are reported for the first time from Iran and R. fragaricus is reported and studied for the second time after its original description. The results of the phylogenetic analyses based on the sequences of the D2-D3 expansion region of the 28S, ITSl-rRNA and the partial 18S rRNA genes were provided for the studied species, confirming their differences from each other and determining the position of them and their relationships with closely related taxa. Also, the validity of Plesiorotylenchus is discussed on the basis of molecular data and its synonymisation (with only one sequence) with Rotylenchus is accepted. [ABSTRACT FROM AUTHOR]

The stubby-root nematode genus Paratrichodorus comprises species of plant polyphagous ectoparasitic nematodes distributed worldwide and a few of them are plant virus-vectors (tobravirus). This is one of the most difficult nematode genera in terms of species identification, since it is phenotypically conserved with closely related species and is highly sensitive to the specimen fixation and preservation processes. Using an integrative and multidisciplinary taxonomy framework, we determined species boundaries among the Paratrichodorus populations from a P. allius species-complex sampled in cultivated and natural ecosystems across Spain. We support the hypothesis that nematode diversity of the P. allius species-complex remains underestimated and describe here a total of eight new species on the basis of detailed morphological and molecular characterization of 16 Paratrichodorus populations: Paratrichodorus asidonaensis sp. nov. Paratrichodorus benalupensis sp. nov. Paratrichodorus hinogerus sp. nov. Paratrichodorus litoralis sp. nov. Paratrichodorus paraallius sp. nov. Paratrichodorus rocianerus sp. nov. Paratrichodorus tarifaensis sp. nov. and Paratrichodorus uliaensis sp. nov. This study emphasizes the importance of properly applying a broad taxonomic framework in plant-parasitic nematodes. It is also relevant for plant health, since it correctly delimits species morphologically closed to the virus vector nematode, P. allius , and gives proper molecular markers for its unequivocal identification. [ABSTRACT FROM AUTHOR]

Abstract A survey of nematodes associated with the red palm weevil Rhynchophorus ferrugineus was conducted in southern Italy in 2015 and 2016 in order to create a species inventory and obtain data about nematode biodiversity. A total of 70 insect samples (pupae and adults) were collected from infested Phoenix canariensis, Phoenix dactylifera, and Chamaerops humilis palms in three Italian Regions: sampling took place at 11 locations in Apulia, 1 in Basilicata, and 1 in Sardinia regions. Individual insects were dissected to determine nematode presence, and different nematode species were also recovered from red palm weevil cocoons collected at the sites in Apulia. Individual nematodes were molecularly identified by sequencing the ITS, D2‐D3 expansion domains of the 28SrRNA gene and the mitochondrial COI and inferring the phylogenetic relationships. The insect‐associated nematofauna identified belonged to the families Rhabditidae, Cephalobidae, and Diplogastridae. Just two nematode species, Teratorhabditis synpapillata and Mononchoides macrospiculum, were always found in association with adult insects and cocoons taken from all sampling sites. This paper reports on the biodiversity of the nematodes associated with R. ferrugineus and on current knowledge of the specific habitat of specialized and divergent entomophilic nematodes.

Morpho-biological notes and histopathology, based on LM and SEM observations, of the fig cyst nematode Heterodera fici isolated from Ficus carica roots, collected in home and public gardens of Apulia region, southern Italy, are described and illustrated. Seventy-five localities throughout the Apulia region were sampled and one-quarter of the sampled localities had fig roots infested with H. fici, with population densities ranging from 44 to 180 cysts/100 ml of soil. All attempts to detect H. fici on ornamental Ficus spp. as well as on imported bonsai in Italy were unsuccessful. Morphometric characters of the Italian population conform to those of the type and re-description populations reported for H. fici. Molecular analysis using ITS, D2–D3 expansion domains of the 28S rRNA, and the partial 18S rRNA sequences of H. fici newly obtained in this study matched well with the corresponding sequences of H. fici present in the GenBank database. Phylogenetic trees confirmed and supported the grouping of H. fici in the Humuli group. Heterodera fici completes its embryogenic development in 14–16 days at 25 °C. Post-invasion development and maturity in the roots of F. carica seedlings is completed in 64–68 days at 25–28 °C with juveniles and adults showing different parasitic habits, being endoparasitic and semi-endoparasitic respectively. The establishment of permanent feeding sites that consist of the formation of large syncytia causes anatomical modification of vascular elements and general disorder in the root stelar structures. Syncytia structures associated with mature females showed different degrees of vacuolisation, numbers of syncytial cells, and contained nuclei and nucleoli which were constantly hypertrophied.

Severe infections of parsley plants and soil infestations with Meloidogyne javanica during an autumn surveys for the pathogenic root-knot nematode infestations were found in Monopoli at Bari province in Southern Italy. This unusual severe infection of parsley, considered a winter crop, was possibly instigated by a very warm autumn from the previous year. Nematodes were extracted from soil samples according to the Coolen’s method. Morphological analysis (based on stylet length, tail length and shape, adult females perineal pattern, excretory pore position and Ep/stylet ratio) and molecular studies were used for the nematode characterization and identification. In the soil of infested area a severely deformed root systems were observed, showing a galling rate = 2.5 - 4 (scale 0-5) and a soil nematode population densities ranging from 350 to 2,730 eggs and J2 per 5 g of fresh root. M. javanica attack on parsley roots is a limiting factor for plant growth. Considering that curly-leaf parsley varieties resistant to the nematodes are not yet available control strategies must be focused on reduction of soil infestation level below tolerance limit of the target nematode species. Due to the higher cost and reduced availability of fumigant and non-fumigant nematicides, soil solarization, organic amendments or biological control approaches should be preferably used as alternatives.

Plant-parasitic nematodes (PPNs) interact with plants in different ways, for example, through subtle feeding behavior, migrating destructively through infected tissues, or acting as virus-vectors for nepoviruses. They are all obligate biotrophic parasites as they derive their nutrients from living cells which they modify using pharyngeal gland secretions prior to food ingestion. Some of them can also shield themselves against plant defenses to sustain a relatively long lasting interaction while feeding. This paper is centered on cell types or organs that are newly induced in plants during PPN parasitism, including recent approaches to their study based on molecular biology combined with cell biology-histopathology. This issue has already been reviewed extensively for major PPNs (i.e., root-knot or cyst nematodes), but not for other genera (viz. Nacobbus aberrans, Rotylenchulus spp.). PPNs have evolved with plants and this co-evolution process has allowed the induction of new types of plant cells necessary for their parasitism. There are four basic types of feeding cells: (i) non-hypertrophied nurse cells; (ii) single giant cells; (iii) syncytia; and (iv) coenocytes. Variations in the structure of these cells within each group are also present between some genera depending on the nematode species viz. Meloidogyne or Rotylenchulus. This variability of feeding sites may be related in some way to PPN life style (migratory ectoparasites, sedentary ectoparasites, migratory ecto-endoparasites, migratory endoparasites, or sedentary endoparasites). Apart from their co-evolution with plants, the response of plant cells and roots are closely related to feeding behavior, the anatomy of the nematode (mainly stylet size, which could reach different types of cells in the plant), and the secretory fluids produced in the pharyngeal glands. These secretory fluids are injected through the stylet into perforated cells where they modify plant cytoplasm prior to food removal. Some species do not produce specialized feeding sites (viz. Ditylenchus, Subanguina), but may develop a specialized modification of the root system (e.g., unspecialized root galls or a profusion of roots). This review introduces new data on cell types and plant organs stimulated by PPNs using sources varying from traditional histopathology to new holistic methodologies.