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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.
Summary
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).
Summary
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.
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.
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.
Summary
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.
Summary
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.
Abstract
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.
Abstract
The first occurrence of soybean cyst nematode, Heterodera glycines, on beans in Iran was documented when a cyst-forming nematode was detected in a commercial common bean (Phaseolus vulgaris) field in Iran and subsequently identified as H. glycines. The population was identified as HG Type 0. Host suitability of the 11 P. vulgaris cultivars most commonly grown in the country were evaluated with that population in pot and field trials. Pot assays were conducted in a growth chamber and nematode reproduction on the cultivars was compared. In the field trials, host suitability of the tested entries was evaluated in a field naturally infested with H. glycines. In both the pot and field experiments, most of the common bean cultivars were susceptible or moderately susceptible to the HG Type 0 populations of H. glycines. Common bean cvs Sayad and Dehghan were classified as moderately resistant in pot trials and were moderately resistant and moderately susceptible, respectively, in field trials. The occurrence of H. glycines in commercial bean production fields and lack of high levels of resistance of the commonly grown P. vulgaris cultivars could severely affect common bean and soybean production programmes in Iran.
Lelenchus brevislitus n. sp. is described and illustrated based on morphological, morphometric and molecular data. The new species is characterised by having females with slender, 452-488 μm long, body lateral field vestigial as a plain simple band under scanning electron microscopy (SEM) in vulval region and absent in proximal and distal body ends, cephalic region short, ca 2 μm high, conical and truncate in anterior end in lateral view under SEM, dorso-ventrally flattened, amphidial pouches pocket-shaped and large under light microscopy (LM), their apertures short (ca 1 μm long in SEM) longitudinal sinuous slits remarkably wide near the small oral disc and significantly narrowing posteriad stylet, slender. 6.5-8.0 μm long, developed median bulb with distinct valvular plates, monodelphic-prodelphic reproductive system having a short post-vulval uterine sac (PUS), transverse vulval slit (V = 47.5-51.7) bearing small lateral membranes on each side, long filiform female tail (154-170 μm, c = 2.8-3.1, c′ = 21.5-28.3), and males unknown. The new species is considered to be a cryptic species inside the Tylenchidae. Morphological comparisons with all species of the genus are discussed. Phylogenetic studies were performed for further characterisation of the new species, and the results, using nearly full length 18S rDNA data, revealed it formed a clade with an isolate of L. leptosoma, both of which are in a sister clade with an isolate of Sakia. In a reconstructed phylogenetic tree using partial 28S rDNA sequences, the new species formed a monophyletic group, again with L. leptosoma, a sister clade to some Malenchus spp.