Two populations of Xiphinema ingens were recovered and
characterised based on morphological, morphometric and molecular data.
Interesting morphological variation was observed on the nature of
differentiation in uterus of females between both populations,
i.e. one population had only a pseudo-Z-organ in the shape
of globular bodies, whilst the second population had a similar pseudo-Z-organ
but also had crystalloids which varied in size and number and were located near
the pseudo-Z-globules or sometimes at some distance from them towards the
vagina. Variation was also observed in the shape of tail of juveniles within
each population as well as between two recovered populations. Both populations
had the same range of morphometric data and formed a fully supported clade in
both Bayesian inference (BI) and maximum likelihood (ML) methods of phylogenetic
analyses using partial sequences of 28S rDNA D2-D3 and ITS1 regions. The two
populations of X. ingens formed a clade with another
Xiphinema species native to Iran (X.
castilloi) in 28S and two species, X.
macroacanthum and X. bernardi, in ITS1 trees.
Ditylenchus acantholimonis n. sp. is described based on morphological, morphometric and molecular characters. It was isolated from the rhizosphere soil of Acantholimon sp. in Golestan province, Iran, and is mainly characterised by having four lines in the lateral field, a pyriform to bottle-shaped offset pharyngeal bulb, post-vulval uterine sac 36.6-56.1% of the vulva to anus distance long, and a subcylindrical to conical tail with widely rounded tip. It is further characterised by short to medium-sized females, 480-617 μm long, with a fine stylet having small rounded knobs, V = 80.8-83.6, c = 11.0-13.8, c′ = 3.3-4.6, and males with 16.0-17.0 μm long spicules. The new species was morphologically compared with six species having four lines in their lateral field, rounded tail tip and comparable morphometric data namely: D. dipsacoideus, D. emus, D. exilis, D. paraparvus, D. sturhani, and D. solani. It was also compared with two species, D. ferepolitor and D. angustus, forming a maximally supported clade in the 18S tree. The phylogenetic analyses using the maximal number of Anguinidae and several Sphaerularioidea genera based upon partial 18S and 28S rDNA D2-D3 sequences revealed that Ditylenchus is polyphyletic. In the 18S tree, the new species formed a clade with D. ferepolitor (KJ636374) and D. angustus (AJ966483); in the 28S tree it formed a poorly supported clade with D. phyllobios (KT192618) and Ditylenchus sp. (MG865719).
Aphelenchoides primadentus n. sp. is described and illustrated based on its morphological, morphometric and molecular characters. It was recovered from natural forests of northern Iran in association with mosses. The new species is characterised by its body length of 502-613 μm in females and 461-564 μm in males, presence of three lines in the lateral fields, a low lip region slightly offset by a shallow depression, 11.1-13.8 μm long stylet in females, its conus being longer than the shaft (m = 53.0-68.5) and bearing well-developed, rounded basal knobs, the excretory pore located at ca one body diam. posterior to the metacorpus, a conical tail with a multipapillate terminus or with a single, warty, wide mucron-like structure at the tip, and males with 19-22 μm long arcuate spicules that lack a well-developed condylus and rostrum. The new species was morphologically compared with species of the genus having three lines in the lateral field and a multipapillate tail tip or tail with warty mucron, namely A. iranicus and A. heidelbergi. Compared to A. ensete, A. huntensis and A. gorganensis, three species with a multipapillate tail tip or warty mucron at the tail tip, the new species has a basic difference in the number of lines in the lateral field and, compared to two species, A. composticola and A. petersi, which have three lines in the lateral field and a similar overall morphology, the new species has basic differences in tail tip morphology. The results of phylogenetic analyses using partial sequences of ribosomal small subunit RNA (SSU) and mitochondrial cytochrome c oxidase 1 (COI mtDNA) genes revealed there is currently no sequenced species of the genus phylogenetically close to the new species being sequenced for these two genomic and non-genomic regions. The new species forms a clade with A. ritzemabosi in SSU, and three other species, A. besseyi, A. ritzemabosi and A. fujianensis, in the COI tree.
Paurodontella gilanica n. sp. is described and illustrated based on morphological, morphometric and molecular characters. The new species is characterised by its small body size, four lines in the lateral field, weak stylet with minute asymmetrical knobs, female reproductive system lacking a diverticulum but with small post-vulval uterine sac, elongate conoid tail with pointed, sometimes filiform, tip, males common with small spicules and cloacal bursa not reaching tail tip. Morphological differences between the new species and seven known species of the genus, namely P. asymmetrica, P. auriculata, P. balochistanica, P. minuta, P. myceliophaga, P. parapitica and P. persica, are discussed. The new species is also compared with four known species of Paurodontus having four lines in the lateral field. Using a 1123 nt long partial 18S rDNA sequence of the new species to reconstruct the phylogenetic relationships revealed that it formed a clade with members of the Sphaerulariidae and Paurodontidae. Using a 746 nt long partial sequence of the 28S rDNA D2-D3 segment revealed that P. gilanica n. sp. formed a clade with Abursanema iranicum in both Bayesian inference (BI) and maximum likelihood (ML) analyses with 0.99 Bayesian posterior probability (BPP) and 89% bootstrap support value (BS). The morphological affinities of Paurodontella and Paurodontus are discussed.
A population of Neolobocriconema serratum was recovered from the rhizosphere of Hosta sp., northern Iran, for the first time. It was studied using morphological and molecular data and new morphological observations were made. The Iranian population is characterised by females having 37-43 body annuli, their outer margin ornamented with 12-14 small lobe-like outgrowths under light microscopy, anastomoses occur sparsely in some females and the succeeding annulus is usually anteriorly bent opposite to the vulva. The cephalic region has a single smooth wavy annulus with grooves and is separated from the first, wider body annulus by a very short neck. Four prominent discoid submedian lobes and two lateral pseudolips present, appearing two layered (i.e., one above the other) in scanning electron microscopy (SEM). Body 487-607 μm long, stylet 85-93 μm long with rounded to anchor-shaped knobs, ovary very long, vulva generally closed, but open in some specimens under SEM. Tail conoid with bluntly rounded end and males absent. The recovered population agreed well with the type population based upon the morphometric data and female morphology. In having an almost identical morphology and morphometrics, N. allantoideum is proposed as a junior synonym of N. serratum. The molecular phylogenetic analyses were done by using near-full-length sequences of the small subunit ribosomal DNA (SSU rDNA), the internal transcribed spacer 1 (ITS1 rDNA) and the mitochondrial cytochrome c oxidase subunit I (COI mtDNA). The Iranian population of this species formed a clade with three other populations of the species in the SSU rDNA, and with one population in both the ITS1 rDNA and the COI mtDNA trees using Bayesian inference.
The soybean cyst nematode, Heterodera glycines, is of major economic importance and widely distributed throughout the world. The effect of H. glycines HG Type 0 on seed yield of susceptible and resistant soybean cultivars was assessed with and without nematicide application in two naturally infested fields in Iran. Soybean cvs BP (susceptible) and DPX (resistant) were arranged in a randomised complete block design and fenamiphos 10G was used in-furrow as a treatment. The population levels of eggs and second-stage juveniles of H. glycines were determined in soil samples collected at planting and harvesting time. Although no above-ground symptoms of nematode infection were visible, mean yield was 48% greater for the resistant cultivar compared with the susceptible cultivar. The yield of cv. BP increased by 16% in plots treated with fenamiphos compared with untreated plots. The resistant cultivar suppressed the reproduction rate of H. glycines. Seed composition, including protein and oil, did not show significant differences between resistant and susceptible cultivars. This is the first demonstration of the yield loss caused by the soybean cyst nematode in Iran.
Ektaphelenchoides shiroodensis n. sp. is described and illustrated based upon morphological, morphometric and molecular data. It was recovered from the bark samples of a dead alder tree (Alnus sp.) from countryside around Shirood city, Mazandaran province, in the north of Iran. The new species is characterised by 768-985 μm long females, its lip region separated from the body contour by constriction, lateral field with three barely visible lines, forming two weak bands, 26-29 μm long stylet with wide lumen without conophore and basal swellings, excretory pore always at the level with median bulb, post-vulval uterine sac (PUS) 43-76 μm long, elongate conoid posterior body region ending to a long filiform part with pointed tip, males common with dorsally convex conical tail ending to a short narrower region with pointed tip, seven precloacal + cloacal + caudal papillae and arcuate spicules with wide condylus, blunt rostrum and simple end. Based upon the similar posterior body region (‘tail’) and comparable PUS length, the new species was compared to three known species, viz., E. attenuata, E. hunti and E. pini. Comparisons with the aforementioned species and similar species under the genus Seinura are discussed. The phylogenetic affinities of the new species, based upon two partial small and large subunit ribosomal DNA (SSU and LSU rDNA D2-D3) sequences, are discussed. Furthermore, several ektaphelenchid and seinurid species previously described from Iran were recovered in the present study, sequenced for their aforementioned genomic markers, and included in the phylogenetic analyses.
In a survey of the family Pratylenchidae from Iran three known species of the
genera Hirschmanniella, Pratylenchoides and Zygotylenchus were found. Their
similarities to and differences from closely related species, their
distribution and their intraspecific variations are discussed. In some
specimens of Zygotylenchus guevarai the spermatheca has numerous cells which
may indicate a relationship of this genus with Meloidogyne. In Iranian
populations of Pratylenchoides ritteri a vast range of morphological
variations was observed. However, the head en-face view was the same for all
populations. It seems that the pharyngeal terminal bulb contains more than
three nuclei in most specimens. Hirschmanniella anchoryzae and P.ritteri
which were studied by light microscopy (LM) and scanning electron microscopy
(SEM) are reported for the first time from Iran. Quelques Pratylenchides
d'Iran (Nematoda: Tylenchina) - Lors d'une enquête sur la famille des
Pratylenchidae en Iran, trois espèces connues des genres Hirschmanniella,
Pratylenchoides et Zygotylenchus ont été trouvées. Leur ressemblances,
différences avec les espèces très proches, leur répartition et leur
variations intra spécifiques sont discutées. Chez quelques spécimens de
Zygotylenchus guevarai, la spermathèque possède des cellules nombreuses, ce
qui pourrait indiquer un relation de ce taxon avec le genre Meloidogyne.
Chez les populations iraniennes de Pratylenchoides ritteri, une large gamme
de variation morphologique a été observée. Cependant, la morphologie de
l'extrémité antérieure était identique pour toutes les populations. Il
semble que le bulbe pharyngien terminal contienne plus de trois noyaux dans
la plupart des spécimens. Hirschmanniella anchoryzae et P.ritteri qui ont
été étudiés en microscopie optique (LM) et électronique à balayage (SEM)
sont signalés pour la première fois en Iran.
Synonchium iranicum sp. n. and Richtersia bispinata sp. n. are described from the Persian Gulf and their relationships investigated using SSU phylogenetic analyses. Synonchium iranicum sp. n. is characterised by a buccal cavity with three equally sized mandibles, each with five small teeth, a rounded tail with three distinct caudal glands and distinct duct, males without gubernaculum and supplements, and short spicules. Richtersia bispinata sp. n. is characterised by multispiral amphids with 3.0-3.5 turns in males and 2.0-2.5 turns in females, cuticle with numerous, irregularly arranged, simple spines in the cervical region, 20-25 longitudinal rows of double spines in the mid-body region, 15-25 longitudinal rows of simple spines in the tail region, and the left spicule markedly longer than the right one. We provided the first near-full-length small subunit ribosomal DNA (SSU rDNA) sequences for both newly described species, as well as cytochrome c oxidase I (COI), and provided D2-D3 expansion segments of large subunit ribosomal DNA (LSU rDNA) sequence for the new species of Richtersia. Our SSU phylogenetic analyses confirmed the placement of Synonchium iranicum sp. n. within the Selachinematidae, and suggested that the selachinematids may form a distinct clade from other chromadorids Our phylogenetic analyses indicated that Richtersia should not be classified within the Selachinematidae as suggested by some authors. Instead, we propose that Richtersia should be placed within the Desmodorida. Although Richtersia differs from Desmodorida in the arrangement of cephalic sensilla, it shares the golden body colouration characteristic of desmodorids in glycerin preparations, the same structure of genital branches in both males and females, and similar cuticular ornamentation to some desmodorid genera (notably Desmodorella).
Three species of the family Tylenchidae, including one new and two known species, are described and illustrated. Atetylenchus minor n. sp. is characterised by its short body length of 633 (558-691) μm, MB = 45 (41-46), lateral field with four crenate incisures, stylet 12.0 (11.5-12.5) μm long, without distinct basal knobs but with swollen arms of the shaft at its base, V = 56.3 (53.7-59.3), absence of lateral vulval membranes, and conical tail 57 (51-62) μm long with a rounded tip. Morphological differences of the new species with four known species of the genus, namely A. abulbosus, A. graminus, A. amiri and A. metaporus, are discussed. Molecular phylogenetic studies of the new species using 1089 bp partial sequences of 18S rDNA revealed that the new species formed a clade with an unpublished species assigned to Psilenchus in Bayesian inference (BI) with low Bayesian posterior probability (BPP). This clade forms a sister clade to a major clade containing two species of Psilenchus and several belonolaim species and genera. The same result was achieved using maximum likelihood (ML) analysis. Morphological and molecular phylogenetic studies were also performed on two other species, Malenchus labiatus and Neothada cancellata, using 28S rDNA D2-D3 sequences. In the inferred Bayesian tree, M. labiatus formed a clade with other species of Malenchus with 28S information with maximal support (1.00 BPP), while N. cancellata formed a clade with Boleodorinae, again with maximal (1.00) BPP.