Reza Ghaderi

An updated and annotated checklist of the Dolichodoridae (Nematoda: Tylenchoidea) of Iran

The list of plant parasitic nematodes of the family Dolichodoridae, known from Iran, is updated. 81 species belonging to 13 genera and three subfamilies are included in the list. Data for 29 species are added, of which seven species viz. Neodolichorhynchus phaseoli, Pratylenchoides crenicauda, P. erzurumensis, P. utahensis, Scutylenchus paniculoides, Trophurus impar and Tylenchorhynchus variannus are new records for the Iranian nematofauna. The list of species, further information on their morphometrics, references, referring to full or partial descriptions, associated plants, geographical distribution and some taxonomic remarks are provided. More detailed studies on some doubtful populations are proposed. The information on the taxonomic position of species in different classification schemes, as well as, the tendency of the species to certain climatic condition or ecological niche are provided. Challenges on the reliable identification of this group of nematodes in Iran are discussed and finally, suggestions were proposed for future studies.

Phylogenetic relationships of Telotylenchidae Siddiqi, 1960 and Merliniidae Siddiqi, 1971 (Nematoda: Tylenchida) from Iran, as inferred from the analysis of the D2D3 expansion fragments of 28S rRNA gene sequences

Sixteen species, Amplimerlinius globigerus, A. macrurus, Bitylenchus parvus, Merlinius brevidens, M. nanus, Neodolichorhynchus phaseoli, Paramerlinius neohexagrammus, Pratylenchoides alkani, P. ritteri, P. utahensis, Scutylenchus paniculoides, S. rugosus, S. tartuensis, Scutylenchus sp. A, Trophurus impar and Tylenchorhynchus brassicae, from the families Telotylenchidae and Merliniidae were collected from different locations in Iran and molecularly characterised using sequencing of the D2D3 expansion fragments of the 28S rRNA gene. Morphometrics and light micrography for studied species are also provided as vouchers. The phylogenetic relationships of Telotylenchidae and Merliniidae with other representatives of the order Tylenchida, as obtained from Bayesian inference and Maximum likelihood analysis of partial 28S rRNA gene sequences, are presented and discussed. The results of phylogenetic analysis were in accordance with classifications in which Bitylenchus and Scutylenchus are considered as separate genera, but Tessellus and Telotylenchus were synonyms of Tylenchorhynchus. The Shimodaira-Hasegawa test of the 28S rRNA gene sequence alignment and trees rejected a large genus concept of Tylenchorhynchus and the constrained monophyly for Belonolaimidae revealed within this family two genera groups: i) Belonolaimus and Ibipora; and ii) Carphodorus and Morulaimus. The present results also support the combination of Pratylenchoides and Merliniinae into a single family, the Merliniidae.

Morphological characterisation of a new and two known species of Ditylenchus Filipjev, 1936 (Nematoda: Anguinidae) from Iran

Ditylenchus sturhani sp. n. from the rhizosphere of grasses in East Azarbaijan province, Northwestern Iran, is described and illustrated. The new species is characterised by a straight to slightly arcuate body 656-865 µm in length, presence of four incisures in each lateral field, slender stylet 10-12 µm in length, pharyngeal basal bulb offset or slightly overlapping the intestine, post-uterine sac 1.0-1.9 vulval body diameter long and conical tail with finely rounded terminus. Differences with closely related species including D. solani, D. ausafi, D. angustus, D. dipsaci, D. drepanocercus, D. obesus and D. gallaeformans are discussed. In addition, Iranian populations of two known species, D. valveus and D. virtudesae, are morphologically characterised.

Description of Amplimerlinius uramanatiensis sp. n. (Nematoda: Merliniidae) and observations on three other species of the genus from Iran

A new species of the genus Amplimerlinius is described and illustrated from the rhizosphere of Vitis sp. from Kurdistan province in western Iran. A. uramanatiensis sp. n. is characterized by having seven to eight head annuli up to the end of the outer extension of the cephalic framework, 29-31 µm long stylet and cylindrical-clavate tail with a thin hyaline region (9-11 µm) and smooth terminus. Furthermore, A. paraglobigerus and A. macrurus were identified and intra-specific variability of A. globigerus was studied in detail, based on 21 populations collected from different regions of Iran. A key and diagnostic compendium to the species of the genus is provided.

Studies on the nematicidal activity of stinging nettle (Urtica dioica) on plant parasitic nematodes

The effect and the potential application of stinging nettle exudates in controlling plant nematodes were investigated. The effect of root exudates of the stinging nettle interplanted with tomato and bean and its potential application as green manure for reducing the population of plant nematodes were also investigated. The results showed that the counts of the nematodes in the base of stinging nettle were significantly lower than those in the 2 m radius from the plant. Comparison of mean counts of the nematodes showed a differential controlling effect of stinging nettle exudates on the nematodes. The counts of the nematodes in pots pre-sown with stinging nettle were reduced, while in pots planted with tomato plants the reductions were significantly lower. The application of stinging nettle as green manure in nematode-infected pots planted with tomato/bean caused significant reductions in the counts of the nematodes.

A new and four known species of Diphtherophora (Nematoda: Diphtherophoridae) from Iran, with a diagnostic compendium of its species

A new and four known species of the genus Diphtherophora-D. geraerti sp. n., D. caudata, D. obesa, D. perplexans and D. tenera-were collected and identified from different plants and localities in Iran. Morphological and morphometric characters of Diphtherophora geraerti sp. n. are compared with those of closely-related species, including D. siddiqii, D. brevicollis, D. lata, D. obesa, D. citri, D. vasilevi and D. vitoshae. Females of the new species have a head continuous with the body contour, spear 11-14 µm in length, rod-shaped spermatozoa and conical tail with bluntly rounded to hemispherical terminus. Males have two ventromedian neck papillae located 22-25 and 52-60 µm from the anterior end, and two ventromedian supplements at 11-13 and 75-80 µm anterior from cloacal aperture, respectively. All Diphtherophora species recovered as part of the present study are new records for the Iranian nematode fauna. Finally, a diagnostic compendium is given, to assist with species identification in the genus.

One new and three known species of Geocenamus Thorne & Malek, 1968 (Nematoda: Merliniidae) from Iran

Soil samples collected from different plants and localities in Iran yielded one new and three known species of the genus Geocenamus with tessellated cuticle. Geocenamus conicaudatus n. sp. is characterised by a hemispherical cephalic region, set-off from the rest of body by a constriction, a slender stylet 17-20 µm long with laterally directed knobs, coarsely annulated cuticle with 32-34 longitudinal striae and a conical tail with smooth, finely rounded terminus. Morphological and molecular studies on the populations of G. paniculoides and G. tartuensis indicated that G. paniculoides may be considered as a valid species. Intraspecific variability of some characters of 30 Iranian populations of G. rugosus were studied. An identification key to 32 valid species of the genus Geocenamus is given.

Morphological and molecular data support the monophyletic nature of the genus Pratylenchoides Winslow, 1958 (Nematoda: Merliniidae) and reveal its intrageneric structuring

The genus Pratylenchoides has recently been transferred from the family Pratylenchidae to Merliniidae. To investigate further the relationship between these ‘Pratylenchus-like’ species (residing in the subfamily Pratylenchoidinae) and the subfamily Merliniinae, more than 500 soil samples were collected from various natural and agronomic habitats in the northern and north-western provinces of Iran. In this study, paratypes or populations of 22 species of Pratylenchoides, including the Iranian populations of P. alkani, P. crenicauda, P. erzurumensis, P. laticauda, P. nevadensis, P. ritteri and an undescribed species, were studied. Intra- and interspecies variation of the following characters were investigated: position of the pharyngeal gland nuclei, shape of female and male head, striation of female tail terminus, number of lateral lines at mid-body and in phasmid region for females, presence of intestinal fasciculi, and shape of sperm. Combining morphological and molecular data prompted us to propose two clusters of related Pratylenchoides species. One cluster includes P. crenicauda, P. variabilis and P. erzurumensis, whereas the second cluster consists of P. alkani, P. nevadensis and P. ritteri. Our data point to a sister positioning of P. magnicauda vis-a-vis all Pratylenchoides species included in this research. Analyses of SSU rDNA (for family and subfamily relationships) and partial LSU rDNA sequences (for intrageneric relationships) data revealed: i) the distal and nested positioning of all Pratylenchoidinae within the Merliniidae; ii) the single transition from ectoparasitism to migratory endoparasitism within the family Merliniidae corresponds with the current subfamily partitioning; and iii) support for the monophyletic nature of the genus Pratylenchoides.