A description is provided of Longidorus cholevae sp. n., a bisexual species associated with wild cherry (Prunus avium L.) from the Rila Mountains, Bulgaria. The position of L. cholevae sp. n. among other species of the genus was elucidated by using morphological and molecular data. Phylogenetic analyses were performed of D2-D3 expansion domains of the 28S rRNA and the partial ITS1 containing regions by Neighbor-Joining, Maximum Likelihood and Bayesian Inference methods. The species is characterised by a female body length of 6.1–8.1 mm; long odontostyle (106–129 μm); lip region wide (21.5–24 μm) rounded and continuous with the body profile; amphidial pouches short and wide, funnel-shaped; a posteriorly situated guide ring (30–37 μm); normal arrangement of pharyngeal glands, and short bluntly rounded to hemispherical tail. Four juvenile stages indentified, first stage with elongate conoid tail. Males with 2–4 adanal pairs and a row of 11–13 single ventromedian supplements, spicules 96–120 μm long. Based both on morphological and molecular data the new species appearred to be the most similar witha group of species distributed in Europe sharing common charcters such as amphidial fovea, lip region and tail shapes, and having similar odontostyle and body length: L. poessneckensis, L. caespiticola, L. macrososma, L. helveticus, L. carniolensis and L. pius. An updated list of Longidorus species and a partial polytomous keys to the Longidorus species with long odontostyle (code A45) and short tail (code H1) are provided.

There is a significant knowledge gap with regard to non-filarial nematodes and their relationships, if any, with intracellular bacteria, with only sporadic reports in the literature. An intracellular bacteriaXiphinematobacter, belonging to subdivision 2 of the Verrucomicrobia, was previously reported in the ovaries of three species of the non-filarialXiphinema americanum-group of nematodes. We explored the diversity ofXiphinematobacterin 22 populations ofX. americanumsourced from six continents and conservatively have identified nine phylotypes, six of which have not previously been reported. A geographic basis to the phylotypes was noted with phylotypes A and B only found in Europe, whereas phylotypes F, G, H and I were mainly found in North America. Phylotypes C, D and E showed greater geographical variation. Sequences ofXiphinematobacterfrom this study help to inform the taxonomy of Verrucomicrobia such that the status and composition of Verrucomicrobia subdivision 2 potentially requires reflection.

No abstract

The analysis of the functional diversity of soil nematodes requires detailed knowledge on theoretical aspects of the biodiversity–ecosystem functioning relationship in natural and managed terrestrial ecosystems. Basic approaches applied are reviewed, focusing on the impact and value of soil nematode diversity in crop production and on the most consistent external drivers affecting their stability. The role of nematode trophic guilds in two intensively cultivated crops are examined in more detail, as representative of agriculture from tropical/subtropical (banana) and temperate (apple) climates. The multiple facets of nematode network analysis, for management of multitrophic interactions and restoration purposes, represent complex tasks that require the integration of different interdisciplinary expertise. Understanding the evolutionary basis of nematode diversity at the field level, and its response to current changes, will help to explain the observed community shifts. Integrating approaches based on evolutionary biology, population genetics and ecology can quantify the contribution of nematode fauna to fundamental soil functions. These include carbon transformation, nutrient cycling, pest control and disease transmission. In conclusion, different facets of nematode diversity such as trophic groups, life history traits, variability in body size and/or taxa identities in combination with DNA-based techniques are needed in order to disclose nematode–soil–ecosystem functioning relationships. Further experimental studies are required to define locally adapted and sustainable management practices, through ecosystem-based approaches and nature-based solutions.

No abstract

No abstract

Using ribosomal (18S, ITS1, ITS2, D2-D3 expansion segments of 28S rDNA) and mitochondrial (partial cox1 and nad4) DNA markers in a study of several populations of Xiphinema americanum-group from Europe and Morocco, two cryptic species Xiphinema browni sp. n. (formerly reported as Xiphinema pachtaicum) and Xiphinema penevi sp. n. were revealed. The species are described, illustrated and their phylogenetic relationships discussed. The first species is most similar to Xiphinema parasimile and is a member of Xiphinema simile species complex. The phylogenetic reconstructions inferred from three molecular markers (18S, D2-D3 28S rDNA and cox1) showed that Xiphinema penevi sp. n. is part of Xiphinema pachtaicum-subgroup and is closely related to Xiphinema incertum, Xiphinema pachtaicum, Xiphinema parapachydermum, Xiphinema plesiopachtaicum, Xiphinema astaregiense and Xiphinema pachydermum. Also, a separate “Xiphinema simile-subgroup”, outside the Xiphinema pachtaicum-subgroup and so far consisting only of the parthenogenetic species Xiphinema simile, Xiphinema parasimile, Xiphinema browni sp. n. and probably Xiphinema vallense was formed. New primers for amplification and sequencing of part of the nad4 mitochondrial gene were designed and used.

Xiphinema simile was associated both with cultivated and naturally growing plants, while X. parasimile was recovered from soil around grapevine. Data on the morphological and biometrical characteristics (including juvenile stages) are presented and variations discussed. Pharyngeal bulbus and glandularium length, vaginal and uterine characteristics were shown to be good diff erentiating characters. Th is report of X. parasimile is a new record for Bulgaria as well as a new plant association for the species. Th e description of its male is provided for the fi rst time. Th e Bulgarian population of X. parasimile showed the same pattern as the Serbian population revealed by the RFLP analyses of D1-D2 region.