First Report of Northern Root-Knot Nematode Meloidogyne hapla on Bupleurum chinensis in Gansu Province, China

Bupleurum chinensis is an important traditional medicine with anti-inflammatory and immunomodulatory effects in China (Navarro et al. 2001). So far, the diseases reported on B. chinensis were caused by fungi (rust and root rot) and virus (Cucumber mosaic virus and Broad bean wilt virus 2) (Zhang et al. 2009). However, no diseases caused by nematodes were reported previously. Root-knot nematodes (Meloidogyne spp.) are one of the most destructive plant-parasitic nematodes with strong adaptability and diversity, infecting more than 5,500 plant species (Azevedo de Oliveira et al. 2018). In October 2020, symptoms of dwarf, leaf yellowing and roots with numerous knots on B. chinensis in several fields were observed in Dingxi City, Gansu Province, Northwest China (N 35°19'42″; E 104°2'24″). Subsequently, hundreds of eggs, mature males and females were exuded from dissection of washed root-knots. Morphological characteristics of females, males and J2s were examined under the optical microscope. The perineal patterns of females (n=15) were oval-shaped with a slightly dorsal arches, and the lateral lines and punctations on anus were observed in some specimens. Measurements (mean ± SD, range) of females(n=20): L (body length) = (525.23 ± 59.88 μm, 439.72 to 659.93 μm), W (maximum body width) = (403.92 ± 57.17 μm, 311.01 to 513.34 μm), St (stylet length) = (11.28 ± 1.05 μm, 9.82 to 12.91 μm), MBW (width of the median bulb) = (31.13 ± 3.32 μm, 23.66 to 35.55 μm), MB (distance from anterior end to center of median oesophageal bulb valve) = (64.45 ± 3.44 μm, 58,62 to 71.92 μm), and DGO (dorsal gland orifice to stylet) = (3.79 ± 0.60 μm, 2.72 to 5.00 μm). Male (n=20): L= (1038.25 ± 90.34 μm, 877.28 to 1206.12 μm), St= (18.13 ± 1.48 μm, 15.10 to 20.12 μm), a (body length divided by greatest body width) = (31.77 ± 4.03 μm, 23.29 to 41.16μm), MBW= (10.97 ± 0.78 μm, 9.05 to 12.31 μm), MB= (64.81 ± 3.45 μm, 59.59 to 71.38 μm), DGO= (4.05 ± 0.47 μm, 3.11 to 5.08 μm), and Spic (spicule length) = (22.57 ± 1.91 μm, 19.26 to 26.43 μm). J2 (n=25): L= (381.73 ± 25.85μm, 336.96 to 419.98 μm), St= (10.52 ± 1.03 μm, 9.15 to 12.14 μm), a= (24.35 ± 2.10 μm, 20.45 to 28.29 μm), DGO= (3.02 ± 0.42 μm, 2.42 to 3.79 μm), c (body length divided by tail length) = (8.90 ± 0.86 μm, 7.71 to 10.48 μm), and c' (tail length divided by body width at anus) = (4.18 ± 0.50 μm, 3.47 to 5.04 μm). According to morphological characteristics, root-knot nematode infecting B. chinensis was preliminarily identified as Meloidogyne hapla Chitwood, 1949 (Whitehead 1968). To further verify this result, DNA was extracted from ten individual females, the ITS region and the D2-D3 region of 28S rDNA were amplified using the primer TW81/AB28(GTTTCCGTAGGTGAACCTGC/ ATATGCTTAAGTTCAGCGGGT) (Subbotin et al. 2000) D2A/D3B (ACAAGTACCGTGAGGGAAAGTTG/ TCGGAAGGAACCAGCTACTA) (De Ley et al. 1999), respectively. PCR products were purified and sequenced. The sizes of ITS region and D2-D3 region of 28S rDNA were 557 bp and 762 bp, respectively. The sequence of ITS region (GenBank accession number: OK030559) was 99.46%-99.82% identical to the M. hapla from China (MT490918), New Zealand (JX465560), Australia (AF516722) and Japan (LC030357). The sequence of D2-D3 region of 28S rDNA (GenBank accession number: OK030558) was 99.58%-100.00% identical to the M. hapla from Canada (MW182329), Ethiopia (KJ645432), USA (KP901086) and China (MN446015). Furthermore, fragments obtained using the specific primers of M. hapla (Mh-F/Mh-R) were 462 bp, which also was consistent with that of M. hapla (Feng et al. 2008). Through morpho-molecular characterization, the root-knot nematodes on B. chinensis in China were identified as M. hapla. Six seedlings of B. chinensis were planted in 16 cm diameter, 20 cm deep plastic pots with sterilized soil in the greenhouse at 20-25℃ for pathogenicity test. After planted 21 days, 2000 J2s/pot were inoculated, six seedling uninoculated were used as control. After 90 days, all inoculated plants showed similar symptoms observed in the field, and nematode reproduction factor (final population density/initial population density) was 1.47. Meanwhile, no symptoms were observed on control plants. These results proved that the nematode infecting B. chinensis is M. hapla. To our knowledge, this is the first report of B. chinensis as a new host of M. hapla in China. Bupleurum chinensis is widely planted in Gansu Province, the plant species cultivated across an area of about 19.1 million hectares, accounting for 40% of the China's total output (Wang et al. 2017). The root system of B. chinensis infected M. hapla is stunned and short, seriously affect the quality of medicinal materials, and restrict the development of the local Chinese herbal medicine industry.

Morphological and Molecular Characterization of Nothotylenchus medians and N. similis (Nematoda: Anguinidae) from Southern Alberta, Canada

The nematode family, Anguinidae, is a diverse group of polyphagous nematodes, generally known as fungal feeders or parasites of aerial plant parts. Here, we present the morphological and molecular characterization of adult females of two Nothotylenchus species, N. medians and N. similis, along with host association and geographical distribution data of the genus. Both species are recorded as new reports from Canada and designated as reference populations for future studies. Morphological or morphometrical variation was not observed in the Canadian population of N. medians and N. similis, in comparison with the original description. Phylogenetic analyses based on 18S and D2–D3 of 28S genes placed both species within Anguinidae. Since the biology of the genus Nothotylenchus has not been rigorously characterized, the habitat and distribution information presented in this study will shed some light on the ecology of these nematodes. Notably, the detection of N. medians and N. similis in our nematode inventory survey indicates that considerable Nothotylenchus diversity is hidden in these soils. Consequently, increased surveys and more in-depth research are needed to explore the full diversity of anguinids inhabiting these cultivated areas.

Description of Cryptaphelenchus recticaudatus n. sp. (Aphelenchoidea: Ektaphelenchinae) in Pinus elliottii from the USA

Cryptaphelenchus recticaudatus n. sp. is described and illustrated in Pinus elliottii from the USA. The new species is characterised by the female body 310-431 μm long with distinctly annulated cuticle, lateral fields with four lines, lip region separated from the body by a shallow depression, delicate stylet with small knobs, post-vulval uterine sac short, and rectum and anus invisible. Males are 228-314 μm long, spicules 9.8-12.4 μm long with a well-developed and broad condylus, and seven caudal papillae arranged as a single (P1) and pair (P2) of precloacal papillae plus two pairs of postcloacal papillae. Based upon the general female morphology, the new species most closely resembles C. baujardi and C. iranicus. The morphological differences with the aforementioned species and other species of the genus are discussed. The phylogenetic analyses based on small (SSU) and large subunit (LSU) D2-D3 expansion segments of ribosomal DNA of different individuals of the new species revealed that the new species fell into the Cryptaphelenchus clade in both SSU and LSU trees. The monophyly of the genus was retained after adding newly generated sequences of the new species.

Identification and pathogenicity of Pratylenchus scribneri on tomato in Sichuan Province of People's Republic of China

Root-lesion nematodes (Pratylenchus spp.) are a group of economically important pathogens that have caused serious economic losses in many crops. In 2019, root-lesion nematodes were recovered from tomato (Solanum lycopersicum) root samples collected from Sichuan Province, People's Republic of China (PRC). Extracted nematodes were disinfected, and one individual female was cultured on a carrot disc for propagation at 25 °C by parthenogenesis and designated the SC isolate. Afterwards, the isolate was identified on the basis of morphometric and molecular markers. Both morphometric characters and molecular analysis of the internal transcribed spacer region gene (ITS) of ribosomal DNA, the D2-D3 expansion region of the 28S rDNA gene and the mitochondrial cytochrome oxidase I (mtDNA-COI) gene revealed that the species of root-lesion nematode was Pratylenchus scribneri. The Bayesian tree inferred from the ITS rDNA, 28S rDNA and mtDNA-COI gene sequences also showed that this isolate formed a highly supported clade with other P. scribneri isolates. The pathogenicity of the root-lesion nematode SC isolate on tomato was assessed, showing that tomato was a suitable host for P. scribneri. To the best of our knowledge, this is the first report of P. scribneri on tomato in Sichuan Province, PRC. These are also the first molecular data obtained from P. scribneri on tomato in the PRC, and the pathogenicity of P. scribneri to tomato was studied for the first time. This study provides scientific data for the detection, identification and control of tomato root-lesion nematode disease.

TARANTOBELUS JEFFDANIELSI N. SP. (PANAGROLAIMOMORPHA; PANAGROLAIMIDAE), A NEMATODE PARASITE OF TARANTULAS

Multiple tarantula deaths for a wholesale breeder were reported in 2018. The breeder noticed white discharge in the oral cavities of the tarantulas. Upon inspection, it was discovered that the white discharge was a large group of nematodes intertwined inside the tarantula's oral cavity. We examined the nematodes and propose a new species, Tarantobelus jeffdanielsi n. sp., in the currently monotypic genus Tarantobelus based on a combination of morphological and morphometrical data and unique nuclear rDNA 28S and 18S sequences. Based on phylogenetic analyses, the previously described Tarantobelus arachnicida was relocated, along with T. jeffdanielsi, into the family Panagrolaimidae. We also provide evidence of the ability of T. jeffdanielsi to parasitize Galleria mellonella larvae and the tarantula Grammostola pulchra. The life span and fecundity of the new species were also assessed, resulting in an 11.2-d average life span, and a total fertility rate of 158 nematodes/adult.

On the identity of the genus Epacrolaimus Andrássy, 2000 (Nematoda, Dorylaimida), with new insights into its phylogeny

The type species of the genus Epacrolaimus, Epacrolaimus declinatoaculeatus, is studied from the re-examination of type material of Aporcelaimus vorax, its junior synonym, and the observation of several Iberian populations and a few Iranian specimens. Morphologically, it displays a recognizable morphological pattern characterized by, among other features, the incurved nature of its odontostyle aperture, presence of perioral liplets or lobes, lip region 24–31 μm wide, odontostyle 21–25 μm long and comparatively anterior location of S2N pharyngeal gland nuclei. Nevertheless, variations in some morphological traits (vagina shape and tail shape) and in several morphometrics (body length, uterus length, vulva position, tail length and spicule length) are also noted. Sequences of D2–D3 domains of the 28S rDNA, 18S rDNA and COI mtDNA were obtained from several Iberian populations. Their analyses, in particular those from D2–D3 sequences, revealed the existence of a highly supported clade ((Epacrolaimus + Sectonema) + Metaporcelaimus), with a closer relationship between Epacrolaimus and Palaearctic populations of Sectonema, whereas the remaining aporcelaimid genera occupied placements in other clades. These results are discussed, with especial emphasis on the intricate separation of Epacrolaimus and Sectonema, which display significantly different protruding stomatal structure in spite of their close evolutionary relationship as derived from molecular trees.

Molecular and morphological characterization of the root -lesion nematode, Pratylenchus neglectus, on corn from Henan Province of China

Root-lesion nematodes, Pratylenchus spp., are economically important pathogens because of their detrimental and economic impact on a wide range of crops. In August 2018, two samples of both roots and rhizosphere soil were collected from a corn field in Liangyuanqu of Shangqiu city, Henan Province, China. Root-lesion nematodes were recovered from the roots and soil samples using the modified Baermann funnel extraction method. Both the morphological characters and molecular analysis of the internal transcribed spacer (ITS) and D2-D3 expansion region of 28S ribosomal RNA sequences confirmed that the root-lesion nematode population collected from corn in this study was P. neglectus. Phylogenetic analyses showed that this isolate formed a highly supported clade with other P. neglectus isolates. To the best of our knowledge, this is the first report of P. neglectus on corn in Henan Province of China. This study reports the first partial sequences of 28S D2-D3 region of P. neglectus on corn in China. Due to the great harmfulness of root-lesion nematodes to corn, care should be taken to prevent the spread of P. neglectus to other regions in China. At the same time, further study on the biological characteristics of P. neglectus is needed, which will be helpful to develop corresponding management and control strategies.

Pratylenchus smoliki, a new nematode species (Pratylenchidae: Tylenchomorpha) from the Great Plains region of North America

Pratylenchus smoliki is a new species of root-lesion nematode described from corn-soybean production fields in the Central Great Plains of North America. It is characterized by populations with relatively abundant males, two lip annuli, females with a round functional spermatheca and a conoid to subcylindrical tail with a non-crenate, smooth terminus. In host preference tests, corn and wheat produce the largest nematode populations, whereas sorghum and soybeans produce less than 20% the numbers observed on corn. Scanning electron microscopy reveals that the en face patterns compare to those seen in Pratylenchus pseudocoffeae, P. scribneri, P. hexincisus, and P. alleni. The pattern is described as rectangular to trapezoidal subdorsal and subventral lips adjoining oral disc, but with a clear demarcation between the oral disc and the subdorsal and subventral sectors. A Maximum Likelihood COI tree recognizes P. smoliki as a moderately-well-supported clade with several haplotype subgroups. A Maximum Likelihood partial 28S tree provides strong support for the P. smoliki clade and reinforces the close relationships between species with similar en face patterns. Topotype specimens of P. alleni were demonstrably different from P. smoliki using DNA markers. The geographic range of P. smoliki overlaps with the ranges of P. alleni, P. scribneri, P. neglectus, P. hexicisus, and P. dakotaensis. The observed host range (corn, rye, sunflower, and wheat) suggests that P. smoliki may be native to the tallgrass prairie region of the Great Plains.

Redescription of Ektaphelenchoides compsi Baujard, 1984 (Tylenchina: Aphelenchoididae) isolated from Pinus massoniana in Fujian Province, China

Ektaphelenchoides compsi is redescribed morphologically with new molecular characterisation. It was isolated from a dead Pinus massoniana tree in Ningde City, Fujian Province, China. Detailed morphology of the spicule, female gonad, hemizonid position, arrangement of male caudal papillae and female tail terminus shape are documented. It is characterised by a lateral field with three lines (forming two bands), tripartite stylet 17.8 (17.0-19.4) μm long without basal thickenings, metacorpus rectangular with anterior 40% granular and posterior part weakly muscular, metacorpal valve slightly posterior to middle of metacorpus, excretory pore at level of nerve ring, vagina with thickened walls and strongly developed muscular bundles, vulval lips slightly protuberant, vulval flap absent, distal region of post-vulval uterine sac appearing as a weakly developed oogonia, anus and rectum indistinct, female posterior part (‘tail’) dorsally convex, conical, terminal region contracted into a bluntly pointed tip. The spicules are arcuate, 15.6 (14.3-16.3) μm along the chord, lamina smoothly curved to distal end, capitulum slightly concave, condylus well-developed with broadly rounded tip and slightly depressed at dorsal end, rostrum triangular with finely rounded tip, cucullus absent, and with seven caudal papillae present. The near full length 18S and 28S D2-D3 regions of rRNA genes sequences were characterised. The phylogenetic analyses revealed that the Fujian population of E. compsi grouped with the Zhejiang population of E. compsi, both being morphologically identical.

Characterization of Pterotylenchus cecidogenus in Desmodium ovalifolium cover crop from oil palm plantations in central Colombia

Until recently, the stem gall nematode Pterotylenchus cecidogenus was only registered in eastern Colombia. However, the disease has recently been observed in central Colombian oil palm plantations that use Desmodium ovalifolium as a cover crop. Soil, root, stem, and leaf samples were collected from D. ovalifolium. Plants showed foliar yellowing, leaf drying, and galls within stem nodes. Nematodes were identified, and the distribution, population density, and relative importance of different genera were determined. We performed morphometric and molecular identification of nematodes associated with gall symptoms. The D2-D3 segment of the large subunit-28S of ribosomal ribonucleic acid (RNA) and internal transcribed spacer (ITS) was sequenced, and phylogenetic analysis was performed. P. cecidogenus mainly occurred in the galls and to a lesser extent in the roots and soil. Nematodes were not found in leaf or inflorescence tissue. Morphological and morphometric data confirm the presence of P. cecidogenus in the stems of D. ovalifolium with gall symptoms. This study is the first to report deoxyribonucleic acid (DNA) sequences of P. cecidogenus. Based on D2-D3 and ITS partial sequences, P. cecidogenus is a sister species of the leaf-galling nematode Ditylenchus phyllobius (Sinm. Orrina phyllobia).

Morphological and Molecular Characterization of Quinisulcius curvus from China

A stunt nematode species, Quinisulcius curvus, recovered from the rhizosphere of sea randa (Guettarda speciosa), is described and characterized herein based on integrative taxonomy. Morphometrics and distribution of all reported populations of Q. curvus are also discussed. The Chinese population of Q. curvus displayed slight variation in stylet length; however, the rest of the characters matches well with the original description. This is the first record of Q. curvus from Hainan, China, and the first molecular characterization for this species. Phylogenetic analysis based on partial 18S, 28S and ITS sequences placed Q. curvus with related stunt nematodes species, but clearly separated from them. The present study expanded the geographic record and provided molecular data on Q. curvus from China.

First Report of Three Tylenchidae Taxa from Southern Alberta, Canada

Members of the family Tylenchidae are highly abundant in soil habitats, including agricultural settings, where they play key ecological roles. In the present study, we identified three Tylenchidae species, namely Basiria bhabi, Coslenchus acceptus, and Filenchus vulgaris, using integrative taxonomy. The detailed morphological and morphometric characteristics, distribution, and host associations of each species were also discussed. Phylogenetic analyses of these populations with other Tylenchidae nematodes indicated the presence of divergent lineages in Filenchus and Basiria, whereas Coslenchus appeared to be a monophyletic genus. Herein, we aim to grow awareness about this common but least studied group of nematodes. The species reported in this study are new records for Canada, revealing that the identified nematode diversity in our cultivated areas is relatively underrepresented. Our analyses also provided greater taxonomic resolution and captured rare taxa that might have been missed or misidentified in prior nematode inventory surveys. These findings will add to our understanding of the nematofauna of southern Alberta, thereby providing a more complete picture of existing nematode diversity present in the fields of this highly cultivated region.

Redescription and phylogenetic analysis of the type species of the genus Panagrellus Thorne, 1938 (Rhabditida, Panagrolaimidae), P. pycnus Thorne, 1938, including the first SEM study

The identity of Panagrellus pycnus, the type species of the genus Panagrellus, is discussed after studying specimens from a cultured population collected in Italy that fits the original material of the species. A new characterization is consequently provided as follows: body 0.93–1.32 mm long, lip region continuous with the adjoining body, stoma with gymnostom very reduced, pharynx with not swollen metacorpus, neck 161–203 µm long, excretory pore at level of the metacorpus, post-vulval uterine sac 99–162 µm long or 2.6–3.8 times as long as the body diameter divided in a short tubular proximal part and a long swollen distal part, vulva post-equatorial (V = 63–69), female tail conical elongate with acute terminus (133–170 µm, c = 6.8–8.1, c’ = 4.9–7.0), male tail conical elongate with acute terminus (104–137 µm, c = 7.8–10.9, c’ = 3.6–5.1), and spicules 70–81 µm long having angular hook-like and very curved ventrad lamina ending in a spatulate tip with a refringent forked axis. The evolutionary relationships of this species and the genus Panagrellus, as derived from the analyses of 18S and 28S rDNA fragments, are discussed. Additionally, the phylogenetic relationships among the members of the infraorder Panagrolaimomorpha is studied, being the genus Tarantobelus transferred to the family Panagrolaimidae and the new subfamily Tarantobelinae n. subfam. is proposed to accommodate it.

Description of Spinocephalus tessellatus n. gen., n. sp. (Rhabditida, Cephalobidae) from Iran, a nematode with a new morphological pattern at lip region

A new genus and new species of the family Cephalobidae, subfamily Cephalobinae, named Spinocephalus tessellatus n. gen., n. sp. is described from Iran. Body 0.55-0.67 mm long, cuticle with tessellations, lateral field with two tessellated longitudinal wings, lip region with six triangular lips, primary axils deep and V-shaped with two conoid-elongate guard processes that originate from each lip, secondary axils deep and U-shaped with one thorn-like process (labial probolae?) in lateral view with a small rounded protuberance fused to the oral plate having triradiate symmetry more developed at the acute margin toward each primary axil, oral opening hexagonal, amphids large and clearly rounded to slightly oval, stoma cephaloboid with cheilostom with minute and rounded rhabdia, pharynx cephaloboid with corpus subcylindrical and isthmus very long being 1.4-1.7 times corpus length, nerve ring surrounds the isthmus, excretory pore at the level of the isthmus. Female monodelphic-prodelphic, spermatheca as long as the body diam., post-vulval uterine sac 0.8-1.0 times body diameter, tail conoid with small rounded terminus. Male monorchic, spicules 24-26 µm long, gubernaculum 11-14 µm long, tail conical and ventrally curved with small rounded terminus. Morphological, including SEM observations, and molecular (based on 18S and 28S rDNA) analyses revealed its relationship with the genera Acromoldavicus and Nothacrobeles.

Phylogenetic relationships of the genus Mischonyx Bertkau, 1880, with taxonomic changes and three new species description (Opiliones: Gonyleptidae)

The type species of Mischonyx Bertkau 1880, Mischonyx squalidus, was described based on a juvenile. The holotype is lost. Based on a revision of publications, the genus includes 12 species, all in Brazil. The objectives of this research are: to propose a phylogenetic hypothesis for Mischonyx based on Total Evidence (TE); propose taxonomic changes based on the phylogeny; and analyze the phylogenetic hypothesis biogeographically. Using the exemplar approach to taxon selection, we studied 54 specimens, 15 outgroups and 39 ingroup taxa using seven molecular markers (28S, 12S and 16S ribosomal genes, citochrome oxidase subunit I gene, carbamoyl-phosphate synthetase gene, internal transcribed spacer subunit 2 and histone H3 gene), totaling 3,742 bp, and 128 morphological characters. We analyzed the dataset under three optimality criteria: Maximum likelihood (ML), Maximum parsimony (MP) and Bayesian. We discuss the transformation of character states throughout the phylogeny, the different phylogenetic hypotheses using different datasets and the congruence of evidence between the clades obtained by the phylogenetic analysis and the biogeographical hypothesis for the Atlantic Forest areas of endemism. We estimate that Mischonyx clade diverged 50.53 Mya, and inside the genus there are two major clades. One of them cointains species from Paraná, Santa Catarina, South of São Paulo and Serra do Mar Areas of Endemism and the other has species from Espinhaço, Bocaina, South coast of Rio de Janeiro and Serra dos Órgãos Areas of Endemism. The first split inside these two clades occurred at 48.94 and 44.80 Mya, respectively. We describe three new species from Brazil: Mischonyx minimus sp. nov. (type locality: Petrópolis, Rio de Janeiro), Mischonyx intervalensis sp. nov. (type locality: Ribeirão Grande, São Paulo) and Mischonyx tinguaensis sp. nov (type locality: Nova Iguaçu, Rio de Janeiro). The genus Urodiabunus Mello-Leitão, 1935 is considered a junior synonym of Mischonyx. Weyhia spinifrons Mello-Leitão, 1923; Weyhia clavifemur Mello-Leitão, 1927 and Geraeocormobius reitzi Vasconcelos, 2005 were transferred to Mischonyx. Mischonyx cuspidatus (Roewer, 1913) is a junior synonym of M. squalidus Bertkau, 1880. In the results of the phylogenetic analyses, Gonyleptes antiquus Mello-Leitão, 1934 (former Mischonyx antiquus) does not belong in Mischonyx and its original combination is re-established. As it is now defined, Mischonyx comprises 17 species, with seven new combinations.

Bacterial communities associated with Zeldia punctata, a bacterivorous soil-borne nematode

Soil inhabiting organisms are important determinants of agroecosystem productivity. Understanding the composition, the abundance, and the type of interactions established by soil microorganisms is therefore crucial to design strategies to improve agricultural practices and agroecosystem management. In this study, we collected Zeldia punctata nematodes in maize fields in South Africa and profiled their associated bacterial communities using next-generation sequencing. We observed that Z. punctata nematodes establish associations with ecologically diverse bacterial species. The most abundant species observed are Pseudomonas syringae, a phytopathogenic bacterial complex; Lactobacillus paraplantarum, a broadly distributed bacterial species that is present in soils, water bodies, and animal intestinal tracts and has certain probiotic and antimicrobial properties; and Melissococcus plutonius, a serious pathogenic bacterial species that causes brood disease in honeybees. Our study contributes to a better understanding of the soil bacterial communities associated with nematodes in maize agricultural soils in South Africa and unravels the presence of diverse detrimental and beneficial nematode-associated bacteria.

Comparative study of four known species of the genus Acrobeles von Linstow, 1877 (Nematoda, Cephalobidae) with 'single' and 'double' cuticle from coastal dunes in Spain

The nematode genus Acrobeles is composed of two morphological groups distinguished by the presence ('double' cuticle) or absence ('single' cuticle) of the refringent inner layer of the cuticle. In the present study, four species of this genus, two with 'single' cuticle (Acrobeles ciliatus and Acrobeles cylindricus) and two with 'double' (Acrobeles aenigmaticus and Acrobeles complexus) are studied from coastal dunes in Spain. This study provides detailed morphological and morphometrical analyses for the four species, while molecular analysis, based on 18S and 28S ribosomal DNA, is provided for A. complexus. The four species are studied with scanning electron microscopy, which is obtained for the first time for A. cylindricus. These analyses revealed morphological and molecular differentiations between both groups, appearing as two related monophyletic entities. The subgenera Acrobeles and Seleborca, formerly considered as separate genera, are proposed to accommodate both groups.

A new aphelench nematode, Basilaphelenchus brevistylus n. sp. (Aphelenchoididae: Tylaphelenchinae) from Pinus massoniana in China

Basilaphelenchus brevistylus n. sp. was isolated from masson pine (Pinus massoniana) in Guangdong province, China. The new species is characterized by an offset lip region, short stylet (female stylet 4.5-5.5 μm and male stylet 4-5 μm long) with three elongate posteriorly directed knobs, posteriorly located metacorpal valve and lateral field composed of three lines. The female has an elongate postuterine sac and a short conical tail, uniformly narrowing toward a sharp tip, or tapering to a slightly offset mucronate tip in a few individuals. The male has a conical tail with a sharp terminal mucro, three pairs of caudal papillae, and small arcuate spicules with a bluntly rounded condylus and small pointed rostrum. B. brevistylus n. sp. can be distinguished from all described Basilaphelenchus nematodes by numerous morphological and morphometrical traits, especially the tail morphology of both sexes and stylet length. In addition, molecular phylogenetic trees inferred from rRNA small subunit and D2-D3 expansion domains of large subunit revealed that this nematode belongs to the Basilaphelenchus, and is clearly different from all the other Basilaphelsenchus species.

Integrative Taxonomy Reveals Hidden Cryptic Diversity within Pin Nematodes of the Genus Paratylenchus (Nematoda: Tylenchulidae)

This study delves into the diagnosis of pin nematodes (Paratylenchus spp.) in Spain based on integrative taxonomical approaches using 24 isolates from diverse natural and cultivated environments. Eighteen species were identified using females, males (when available) and juveniles with detailed morphology-morphometry and molecular markers (D2-D3, ITS and COI). Molecular markers were obtained from the same individuals used for morphological and morphometric analyses. The cryptic diversity using an integrative taxonomical approach of the Paratylenchus straeleni-species complex was studied, consisting of an outstanding example of the cryptic diversity within Paratylenchus and including the description of a new species, Paratylenchus parastraeleni sp. nov. Additionally, 17 already known species were identified comprising P. amundseni, P. aciculus, P. baldaccii, P. enigmaticus, P. goodeyi, P. holdemani, P. macrodorus, P. neoamblycephalus, P. pandatus, P. pedrami, P. recisus, P. sheri, P. tateae, P. variabilis, P. veruculatus, P. verus, and P. vitecus. Eight of these species need to be considered as first reports for Spain in this work (viz. P. amundseni, P. aciculus, P. neoamblycephalus, P. pandatus, P. recisus, P. variabilis, P. verus and P. vitecus). Thirty-nine species of Paratylenchus have been reported in Spain from cultivated and natural ecosystems. Although we are aware that nematological efforts on Paratylenchus species in Southern Spain have been higher than that carried out in central and northern part of the country, the present distribution of the genus in Spain, with about 90% of species (35 out of 39 species, and 24 of them confirmed by integrative taxonomy) only reported in Southern Spain, suggest that this part of the country can be considered as a potential hotspot of biodiversity.

First Report of Meloidogyne graminicola on Rice in Henan Province, China

Rice (Oryza sativa) is an important food crop in China and root-knot nematode Meloidogyne graminicola has been one of the most important diseases on rice in recently five years (Ju et al. 2020). In August 2020, rice plants were found to be maldeveloped, yellow leaves and hooked root tips in an irrigated paddy field of Yuanyang County, Xinxiang City, Henan Province. Fifty rice plants were randomly collected and 84.0 percent plants were infected with root-knot nematodes, with root-gall index of 56.0. Then nematodes from rice roots were isolated with 100-μm and 25-μm sieves. A large number of females, some third-stage juveniles (J3s), and a small number of males of Meloidogyne spp. were found in root galls of all samples after dissected, and then were identified and measured under the microscope. In females (n = 20), the perineal pattern was dorsoventrally oval with low and round dorsal arch, and the lateral field was not obvious or absent, striae are usually smooth, with occasional short and irregular striatal fragmentation. The morphological data of females are as follows: body length (BL) = 516.9 ± 72.5 μm (424.2 to 611.6 μm), body width (BW)= 328.4 ± 80.7 μm (232.1 to 437.4 μm), stylet length = 11.2 ± 1.3 μm (7.7 to 13.9 μm), dorsal pharyngeal gland orifice to stylet base (DGO) = 3.9 ± 0.5 μm (3.2 to 4.5 μm), vulval slit length = 24.3 ± 4.6 μm (15.2 to 31.4 μm), vulval slit to anus distance = 16.2 ± 2.5 μm (10.1 to 20.2 μm). Males are long cylindrical, wormlike, with a short round tail. Morphological measurements of males (n = 20) were BL = 1,218.0 ± 150.7μm (1,085.7 to 1,692.2 μm), BW = 34.2 ± 4.6 μm (28.5 to 39.7 μm), stylet = 17.4 ± 0.7 μm (15.9 to 19.3 μm), DGO = 3.6 ± 0.7 μm (2.5 to 4.5 μm), tail = 10.8 ± 2.1 μm (8.0 to 14.8 μm), spicule = 30.3 ± 2.6 μm (24.7 to 36.3 μm). The egg masses from the females were incubated at 28℃ for 48 hours. Measurements of J2s (n = 20) were BL = 444.2 ± 37.8 μm (315.7 to 547.5 μm), BW = 21.2 ± 2.7 μm (16.7 to 26.4 μm), stylet = 14.2 ± 0.3 μm (13.6 to 14.8 μm), DGO = 3.5 ± 0.5 μm (2.7 to 4.5 μm), tail = 70.8 ± 5.1 μm (61.3 to 80.8 μm), hyaline tail length = 21.0 ± 2.5 μm (16.3 to 26.1 μm). These morphological features are consistent with the original description by Golden and Birchfield (1965). DNA of a single female from each sample was extracted for molecular identification. Primer pairs D2A/D3B (5´-ACAAGTACCGTGAGGGAAAGTTG-3´/ 5´-TCGGAAGGAACCAGCTACTA-3´) (De Ley et al. 1999) and the species-specific primers Mg-F3/Mg-R2 (5'-TTATCGCATCATTTTATTTG-3'/ 5'-CGCTTTGTTAGAAAATGACCCT-3') (Htay et al. 2016) were used to amplify D2/D3 region of 28S RNA and the internal transcribed spacer (ITS) region, respectively. The amplified sequences of D2/D3 region (GenBank MW490724, 766 bp) shared 99.9% and 99.7% homology with the sequences of M. graminicola (MN647592, MT576694) isolated from Guangxi and Anhui Province (Ju et al. 2020), respectively, while ITS region sequences (MW487239, 369 bp) shared 100% and 99.7% homology to M. graminicola isolate GXL3 (MN636702) and FQJJ01 (MT159690), respectively. In order to verify the pathogenicity of nematodes, about 300 J2s were inoculated on ten 14-week-old rice (Oryza sativa cv. Nipponbare) planted in pots with sterilized sandy soil, respcectively, and maintained in a greenhouse at 28°C/26°C with a 16h/8h light/dark photoperiod and 75% relative humidity. At 14 days post inoculation, obvious symptoms of hook galls were observed on roots in all inoculated rice plants, and females and males in the same shape as the collected samples were found in the root galls under the stereoscopic microscope. No symptoms were observed on non-inoculated rice plants. After 28 days, the growth of the inoculated rice plants was significantly worse than that of uninoculated ones, with yellow leaves and short plants. These results confirmed the pathogenicity of M. graminicola on rice and it indicated that M. graminicola was already spread from the main rice-producing areas to the wheat and rice rotation areas. To our knowledge, this is the first report of M. graminicola in the Henan Province of China.

Remarkable Cryptic Diversity of Paratylenchus spp. (Nematoda: Tylenchulidae) in Spain

In previous studies, fifteen species of Paratylenchus, commonly known as pin nematodes, have been reported in Spain. These plant-parasitic nematodes are ectoparasites with a wide host range and global distribution. In this research, 27 populations from twelve Paratylenchus species from 18 municipalities in Spain were studied using morphological, morphometrical and molecular data. This integrative taxonomic approach allowed the identification of twelve species, four of them were considered new undescribed species and eight were already known described. The new species described here are P. caravaquenus sp. nov., P. indalus sp. nov., P. pedrami sp. nov. and P. zurgenerus sp. nov. As for the already known described species, five were considered as first reports for the country, specifically P.enigmaticus, P. hamatus, P. holdemani, P. israelensis, and P. veruculatus, while P. baldaccii, P. goodeyi and P. tenuicaudatus had already been recorded in Spain. This study provides detail morphological and molecular data, including the D2-D3 expansion segments of 28S rRNA, ITS rRNA, and partial mitochondrial COI regions for the identification of different Paratylenchus species found in Spain. These results confirm the extraordinary cryptic diversity in Spain and with examples of morphostatic speciation within the genus Paratylenchus.

First report of Meloidogyne hapla on kiwifruit in South Africa

Kiwi is becoming one of the most important fruit in subtropical regions of South Africa with altitudes that confer sufficient chilling requirements. During a survey on biodiversity of plant-parasitic nematodes of kiwi in Magoebaskloof in Limpopo Province, several plant-parasitic nematodes were discovered, with Meloidogyne species occurring at the highest frequency. Nematodes were sampled from roots and the rhizosphere of one stunted Kiwi tree, extracted using the tray method and then fixed. The morphological characters fit well with those of M. hapla. The molecular approach using ITS and 28S rDNA, along with the related phylogenetic analysis, placed the examined population in a group with other populations of M. hapla. Kiwi is being reported as a new host for M. hapla in South Africa.

Morphological and molecular characterizations of Heterodera oryzae in Korea

Rice is one of the most important staple grains in Korea and the largest starch source in addition to its usefulness in the production of beverages. Under different areas and environments of production, various pests and diseases including soil-borne plant pathogens such as plant-parasitic nematodes can compromise rice productivity. In a survey to identify plant parasitic nematodes on rice, cyst nematodes were encountered in rice fields that required characterization and identification. Phylogenetic analysis of the LSU D2-D3 region and ITS region could not separate the studied species from Heterodera elachista. However, phylogenetic analysis of the COI gene of the mitochondrial DNA clearly separated H. elachista from the new species into two different clusters. Combining morphology and molecular diagnostics, the species was identified as Heterodera oryzae belonging to the 'Cyperi' group whose cysts are characterized by vulval cones that are ambifenestrate, underbridge present with bullae. Second-stage juveniles have three incisors in the lateral field with long tails and long hyaline region.

Aphelenchus yinyuensis n. sp. (Tylenchina: Aphelenchoididae) found in Terminalia sp. in China

During a nematode biodiversity survey in Hainan Province, China, Aphelenchus yinyuensis n. sp. was detected in the rhizosphere of Terminalia sp. It is characterized by medium-sized a body of adult nematodes, i.e. 793 (639-877) μm and 756 (647-863) μm for females and males, respectively, with low, rounded, not offset lip region. The lateral field has 10 incisures. The excretory pore is located posterior to the nerve ring. The vagina is not sclerotised and the vulva has simple lips without a flap. The PUS is well developed and forms ca 45 to 83% of the vulva to anus distance. Female tail is straight, cylindrical, ca 2.7 times longer than anal body diam, tail tip broad, and bluntly rounded. Males have four pairs of caudal papillae and spicule 28.7 (25.8-32.3) μm long in the chord and well developed bursa, extending to the tail tip. 18S and 28S rRNA phylogenetic analyses were performed for the new species, and the ITS analysis was not performed due to low posterior probability support. Phylogenetically, the new species grouped with Aphelenchus avenae and this is the first new Aphelenchus species ever described from China.

New Distribution and Molecular Diversity of the Reniform Nematode Rotylenchulus macrosoma (Nematoda: Rotylenchulinae) in Europe

Reniform nematodes of the genus Rotylenchulus are semi-endoparasites of numerous herbaceous and woody plant species roots and occur largely in regions with temperate, subtropical, and tropical climates. In this study, we provide new records of the nematode Rotylenchulus macrosoma in eight European countries (Czech Republic, France, Germany, Hungary, Italy, Romania, Serbia, and Portugal), in addition to the six Mediterranean countries (Greece, Israel, Jordan, Spain, Syria, and Turkey) where the nematode was previously reported. Four new host species (corn, pea, wheat, and an almond-peach hybrid rootstock) are added to the recorded host species (bean, chickpea, hazelnut, peanut, soybean, and wild and cultivated olive). Molecular analyses based on the cytochrome c oxidase subunit coxI and D2-D3 segments of 28S RNA markers showed high diversity and pronounced genetic structure among populations of Rotylenchulus macrosoma. However, the complexity of phylogeographic patterns in plant-parasitic nematodes may be related to the intrinsic heterogeneity in the distribution of soil organisms, a rare occurrence of a species, or the potential human impact associated with agricultural practices.

Cocktail Therapy of Fosthiazate and Cupric-Ammoniun Complex for Citrus Huanglongbing

Huanglongbing (HLB) is a destructive citrus bacterial disease caused by Candidatus Liberibacter asiaticus (Ca.Las) and cannot be cured by current pesticides. Root lesion and Tylenchulus semipenetrans juveniles were observed in HLB-affected citrus tree roots. We hypothesize that root treatment with fosthiazate (FOS) and Cupric-Ammonium Complex (CAC) will improve the root growth and inhibit HLB. CAC is a broad spectrum fungicide and can promote growth of crops. FOS kills Tylenchulus semipenetrans and protects roots from damage by harmful bacteria such as Ca.Las. After 90 days of combination treatment of FOS and CAC through root drenches, the citrus grew new roots and its leaves changed their color to green. The inhibition rate of Ca.Las reached more than 90%. During treatment process, the chlorophyll content and the root vitality increased 396 and 151%, respectively, and starch accumulation decreased by 88%. Transmission electron microscopy (TEM) and plant tissue dyeing experiments showed that more irregular swollen starch granules existed in the chloroplast thylakoid system of the HLB-infected leaves. This is due to the blocking of their secretory tissue by starch. TEM and flow cytometry experiments in vitro showed the synergistic effects of FOS and CAC. A transcriptome analysis revealed that the treatment induced the differential expression of the genes which involved 103 metabolic pathways. These results suggested that the cocktail treatment of FOS and CAC may effectively kill various pathogens including Ca.Las on citrus root and thus effectively control HLB.

First report of Bitylenchus ventrosignatus () associated with wild grass in Botswana

During a survey on the biodiversity of plant-parasitic nematodes of natural areas in Botswana, Bitylenchus ventrosignatus was discovered around the rhizosphere of wild grass. The nematodes were extracted using the tray method and then fixed according to the available protocols. The morphological characters fit well with the description of B. ventrosignatus. In addition, molecular analysis using 18 S and 28 S rDNA indicated 98% (KJ461617) and 95% (KJ461567) similarity with the Spanish population of B. ventrosignatus. The phylogenetic analysis of 18 S and 28 S rDNA placed the examined population with other populations of B. ventrosignatus in a group with a posterior probability support value of 100. According to published literature, this is the first report of B. ventrosignatus from Botswana.

Morphological and molecular characterisation of Longidorus pauli (Nematoda: Longidoridae), first report from Greece

Sampling for needle nematodes was carried out in a grapevine area in Thessaloniki, North Greece and two nematode species of Longidorus (L. pauli and L. pisi) were collected. Nematodes were extracted from 500 cm³ of soil by modified sieving and decanting method, processed to glycerol and mounted on permanent slides, and subsequently identified morphologically and molecularly. Nematode DNA was extracted from single individuals and PCR assays were conducted to amplify D2-D3 expansion segments of 28S rRNA, ITS1 rRNA, and partial mitochondrial coxI regions. Morphology and morphometry data obtained from these populations were consistent with L. pauli and L. pisi identifications. To our knowledge, this is the first report of L. pauli for Greece, and the second world report after the original description from Idleb, Syria, extending the geographical distribution of this species in the Mediterranean Basin.

First report of rice root-knot nematode, Meloidogyne graminicola, infecting Juncus microcephalus in Brazil

Juncus microcephalus plants showing symptoms of root-knot nematode infestation were observed in the municipality of Agudo, Rio Grande do Sul state, Brazil. Based on morphological observation, esterase phenotypes, and molecular analyses of rDNA-ITS and D2-D3 regions of 28S rDNA, the causal agent of the observed symptoms was identified as Meloidogyne graminicola. Pathogenicity of M. graminicola was confirmed by fulfilling modified Koch’s postulates. To our knowledge, this is the first report of M. graminicola in J. microcephalus in Rio Grande do Sul State, Brazil.

Basilaphelenchus hyrcanus n. sp. (Rhabditida: Tylaphelenchinae) associated with bark of a beech tree (Fagus orientalis Lipsky) from northern Iran

Basilaphelenchus hyrcanus n. sp., the sixth species of the newly established genus was isolated during a nematode survey associated with bark samples of beech tree in northern Iran, which differs from the other species by body size, stylet length, metacorpus structure, and tail characters of both genders. The new species is also characterized by elevated cephalic region with sclerotised vestibule, posteriorly directed stylet knobs, well-developed metacorpus filling corresponding body region, position of excretory pore at the level of base of metacarpus, length of post uterine sac by 38–60 μm long, conoid elongate tail by sharp to finely rounded tip in female. Based upon the morphological characteristics and phylogenetic analyses of partial 18 S and D2-D3 28 S rDNA segments, the new species mostly resembles B. magnabulbus. However, B. hyrcanus n. sp. is clearly different from this species by having a longer stylet, different position of the excretory pore, a different male tail tip characters and 4.4 and 13.2% sequence divergences in 18 S and D2-D3 28 S, respectively.

Morphological and molecular characters of Scutellonema brachyurus () from South Africa

During a survey on plant-parasitic nematodes from South Africa, Scutellonema brachyurus was recovered from soil samples collected around the rhizosphere of wild grass in the North West and Limpopo provinces. This species characterized by a hemispherical lip region with four to six annuli, basal lip's annuli with longitudinal incisures, body length 696-904 µm (a = 25.1-33.5; b = 5.0-7.2; c = 48.9-75.3; c' = 0.5-0.9; V = 55-60), stylet 21-27 µm length, tail rounded with 10-19 µm length and spermatheca nonfunctional and male absent. The nblast analysis based on the D2-D3 segment of 28 S rDNA placed South African populations of S. brachyurus with 98% similarity to Greece (KU059494) and 99% similarity to South African (JX472052) S. brachyurus. Besides, nblast of COI of mtDNA showed 98% similarity of the test species with South African populations of S. brachyurus (JX472096; JX472097). The phylogenetic analysis put the South African populations of S. brachyurus together with other S. brachyurus with a 100 posterior probability support. Besides, the measurements, line illustration, and scanning electron microscopy photographs are provided for S. brachyurus from South Africa.

First report of Mesocriconema sphaerocephalum (Taylor, 1936) Loof, 1989 associated with wild grass in Botswana

During a survey on the biodiversity of plant-parasitic nematodes of natural areas in Botswana, Mesocriconema sphaerocephalum was discovered around the rhizosphere of the wild grass. The nematodes were extracted using the tray method and then fixed according to the available protocols. The morphological characters fit well with the M. sphaerocephalum. Besides, molecular aspects using 18S and 28S rDNA were studied. The phylogenetic analysis of 18S and 28S rDNA placed the examined population with other populations of M. sphaerocephalum in a group. According to the knowledge, this is the first report of M. spaherocephalum from Botswana.

Detection of Pratylenchus zeae and P. brachyurus parasitizing plants from the caatinga biome, Ceará, Brazil

Roots of plants characteristic of the Brazilian caatinga showing necrosis symptoms were observed in Iguatu, CE, Brazil. To identify the species, morphological characterization was performed, through the morphometry of females, and molecular analysis of the ITS and 28S rDNA regions. The nematodes Pratylenchus zeae and P. brachyurus were identified as causal agents, confirming pathogenicity by Koch postulates. This is the first report of P. zeae and P. brachyurus in caaatinga plants in the state of Ceará, Brazil.

A new root-knot nematode, Meloidogyne vitis sp. nov. (Nematoda: Meloidogynidae), parasitizing grape in Yunnan

An unknown root-knot nematode was found at high density on grape roots collected from Yunnan Province. Morphometric traits and measurements, isozyme phenotypes, and molecular analysis clearly differentiated this nematode from previously described root-knot nematodes. This new species is described, illustrated and named Meloidogyne vitis sp. nov. The new species can be distinguished from other Meloidogyne spp. by a unique combination of characters. Females display a prominent neck, an excretory pore is located on the ventral region between 23rd and 25th annule behind lips, an EP/ST ratio of approximately 2.5 (1.98-2.96), a perineal pattern with two large and prominent phasmids, and a labial disc fused with the medial lips to form a dumbbell-shaped structure. Males display an obvious head region, a labial disc fused with the medial lips to form a dumbbell-shaped structure, no lateral lips, a prominent slit-like opening between the labial disc and medial lips, a distinct sunken appearance of the middle of the medial lips, and four incisures in the lateral field. Second-stage juveniles are characterized by a head region with slightly wrinkled mark, a labial disc fused with the medial lips to form a dumbbell-shaped structure, a slightly sunken appearance of the middle of the medial lips, a slit-like amphidial openings between the labial disc and lateral lips, and four incisures in the lateral field. The new species has rare Mdh (N3d) and Est phenotypes (VF1). Phylogenetic analysis based on ITS1-5.8S-ITS2, D2D3 fragments of rDNA, and coxI and coxII fragments of mtDNA sequences clearly separated the new species from other root-knot nematodes, and the closest relative was Meloidogyne mali. Meloidogyne mali was collected for amplifying these sequences as mentioned above, which were compared with the corresponding sequences of new species, the result showed that all of these sequences with highly base divergence (48-210 base divergence). Moreover, sequence characterized amplified region (SCAR) primers for rapid identification of this new species were designed.

Characterization of Nothacrobeles lanceolatus Abolafia & Peña-Santiago, 2003 (Rhabditida, Cephalobidae), a typical species of coastal dunes from Spain

The nematode Nothacrobeles lanceolatus was described in arid soils from Cabo de Gata-Níjar Natural Park, province of Almería (Spain). Since then this species has not been found again. In this study, new data on the distribution and morphological, morphometrical and molecular characteristics (based on 18S and 28S ribosomal DNA) of N. lanceolatus is provided. This species is characterized by having a tessellated cuticle, with its inner layer bearing two rows of cuticular punctations per annulus, lips quadrangular with eight pinnae, labial probolae bifurcate with divergent prongs surrounded by pinnae, pharynx with corpus 2.5–4.0 times isthmus length, post-vulval uterine sac 1.4–2.2 times the corresponding body diameter, and female and male tails conical, bearing a conical mucro with acute terminus. The phylogenetic position of this and related species of the genus Nothacrobeles is discussed. Additionally, bacteria (Pasteuria) and fungi (Catenaria, Nematocida) feeding on N. lanceolatus are showed including light microscopy and scanning electron microscopy illustrations.

Global Distribution of the Reniform Nematode Genus Rotylenchulus with the Synonymy of Rotylenchulus macrosoma with Rotylenchulus borealis

Reniform nematodes of the genus Rotylenchulus are semi-endoparasites of numerous herbaceous and woody plant roots that occur largely in regions with temperate, subtropical, and tropical climates. In this study, we compared 12 populations of Rotylenchulusborealis and 16 populations of Rotylenchulusmacrosoma, including paratypes deposited in nematode collections, confirming that morphological characters between both nematode species do not support their separation. In addition, analysis of molecular markers using nuclear ribosomal DNA (28S, ITS1) and mitochondrial DNA (coxI) genes, as well as phylogenetic approaches, confirmed the synonymy of R. macrosoma with R. borealis. This study also demonstrated that R. borealis (= macrosoma) from Israel has two distinct rRNA gene types in the genome, specifically the two types of D2-D3 (A and B). We provide a global geographical distribution of the genus Rotylenchulus. The two major pathogenic species (Rotylenchulusreniformis and Rotylenchulusparvus) showed their close relationship with warmer areas with high annual mean temperature, maximum temperature of the warmest month, and minimum temperature of the coldest month. The present study confirms the extraordinary morphological and molecular diversity of R. borealis in Europe, Africa, and the Middle East and comprises a paradigmatic example of remarkable flexibility of ecological requirements within reniform nematodes.

Morphostatic Speciation within the Dagger Nematode Xiphinema hispanum-Complex Species (Nematoda: Longidoridae)

Dagger nematodes of the genus Xiphinema include a remarkable group of invertebrates of the phylum Nematoda comprising ectoparasitic animals of many wild and cultivated plants. Damage is caused by direct feeding on root cells and by vectoring nepoviruses that cause diseases on several crops. Precise identification of Xiphinema species is critical for launching appropriate control measures. We deciphered the cryptic diversity of the Xiphinema hispanum-species complex applying integrative taxonomical approaches that allowed us to verify a paradigmatic example of the morphostatic speciation and the description of a new species, Xiphinema malaka sp. nov. Detailed morphological, morphometrical, multivariate and genetic studies were carried out, and mitochondrial and nuclear haploweb analyses were used for species delimitation of this group. The new species belongs to morphospecies Group 5 from the Xiphinema nonamericanum-group species. D2-D3, ITS1, partial 18S, and partial coxI regions were used for inferring the phylogenetic relationships of X. malaka sp. nov. with other species within the genus Xiphinema. Molecular analyses showed a clear species differentiation not paralleled in morphology and morphometry, reflecting a clear morphostatic speciation. These results support the hypothesis that the biodiversity of dagger nematodes in southern Europe is greater than previously assumed.

Occurrence of Pratylenchus coffeae Causing Root Rot of Soybean in Shandong Province of China

Soybean (Glycine max L.) is a very important commercial crop in China (Li et al. 2019). Pratylenchus coffeae (Zimmermann, 1898) Filipjev & Schuurmans Stekhoven, 1941, is one of the most important root-lesion nematodes that invade the roots of many crops. In August 2018, five root and soil samples were collected in a soybean field, near Xipan village in Linshu county of Linyi City, Shandong Province, China (Fig. S1), to investigate the occurrence of root-lesion nematodes. The collected plants (cv. Lindou No.10) were growing poorly and the roots showed distinct brown lesions (Fig. S2). Pratylenchus spp. were extracted using the modified Baermann funnel method for 2 days (Hooper et al. 2005). On average, 395 root-lesion nematodes per kg of soil and 36 root-lesion nematodes per gram of fresh roots were extracted. The extracted root-lesion nematodes were disinfected with 0.3% streptomycin sulfate and cultured on carrot disks for propagation at 25°C. The species identification was based on morphological and molecular criteria. Key morphological features were determined for females and males. Measurements of females (n = 16) included body length = 561.0 μm ± 37.6 (standard deviation) (520.5 to 654.0 μm), tail length = 30.0 μm ± 1.9 (27.0 to 33.5 μm), stylet = 16.0 μm ± 0.6 (15.0 to 17.5 μm), a = 28.2 ± 2.3 (23.7 to 31.5), b = 6.4 ± 0.5 (5.7 to 7.3), c = 18.7 ± 1.8 (15.7 to 23.8), and V = 80.8% ± 2.1 (76.5 to 83.8%). Measurements of males (n = 16): body length = 511.0 μm ± 28.1 (range= 475.5 to 566.0 μm), tail length = 26.0 μm ± 1.3 (23.5 to 28.5 μm), stylet = 15.0 μm ± 0.5 (14.5 to 16.0 μm), spicule length = 17.0 μm ± 0.9 (16.0 to 18.5 μm), a = 30.8 ± 1.5 (28.0 to 33.2), b = 6.1 ±0.4 (5.6 to 6.9), and c = 19.8 ± 1.3 (18.1 to 22.2) (Fig. S3). All the morphological features of this population matched the description of P. coffeae (Castillo and Vovlas, 2007). DNA was extracted from an individual female as described previously (Wang et al. 2011). The rDNA-internal transcribed spacer (ITS) region and the D2/D3 region of the 28S rRNA gene were amplified by primers 18S/26S (Vrain et al. 1992) and D2A/D3B (De Ley et al. 1999), respectively. The PCR products were purified and sequenced. The obtained sequences of the ITS region (1,253 bp) and the D2/D3 region of 28S rRNA (781 bp) were deposited in GenBank. The ITS sequences of the root-lesion nematode obtained in this study (GenBank Accession no. MT879294) exhibited 99% identity with several P. coffeae sequences available in the GenBank (e.g., KR106219, MT586756, KY424205, and MN749379), and the obtained D2/D3 region sequence (MT879295) exhibited 100% identity with several P. coffeae sequences (e.g., MT586754, MN750755, MK829009, and MH730447). Both morphological and molecular data confirmed the presence of P. coffeae. To confirm reproduction on soybean, the obtained root-lesion nematode population was used in a greenhouse (25°C) assay to fulfill modified Koch's postulates. About 20 days after sowing, eight pots, each with one soybean plant (Lindou No.10) were inoculated with 1000 P. coffeae. The inoculated plants were kept in 1.5 L pots containing 1.2 L sterilized soil. Eight pots of uninoculated soybeans were used as the control. Ten weeks later, the inoculated roots were washed and brown lesions were observed. The number of nematodes/pot was approximately 7360 in soil and 796 in roots, and the reproduction factor was 8.16. Root-lesion nematodes and symptoms were not observed in control groups. P. coffeae has only been reported on soybean in Zhejiang (Wei et al. 2013) and Henan Province (Li et al. 2019) of China. To our knowledge, this is the first report of P. coffeae infecting soybean in Shandong Province, China. Since the root-lesion nematode can cause considerable damage to soybean, care should be taken to prevent the spread of P. coffeae to other regions in China.

Ficus microcarpa Bonsai “Tiger bark” Parasitized by the Root-Knot Nematode Meloidogyne javanica and the Spiral Nematode Helicotylenchus dihystera, a New Plant Host Record for Both Species

In December 2017, a Ficus microcarpa “Tiger bark” bonsai tree was acquired in a shopping center in Coimbra, Portugal, without symptoms in the leaves, but showing small atypical galls of infection caused by root-knot nematodes (RKN), Meloidogyne spp. The soil nematode community was assessed and four Tylenchida genera were detected: Helicotylenchus (94.02%), Tylenchus s.l. (4.35%), Tylenchorynchus s.l. (1.09%) and Meloidogyne (0.54%). The RKN M. javanica was identified through analysis of esterase isoenzyme phenotype (J3), PCR-RFLP of mitochondrial DNA region between COII and 16S rRNA genes and SCAR-PCR. The Helicotylenchus species was identified on the basis of female morphology that showed the body being spirally curved, with up to two turns after relation with gentle heat, a key feature of H. dihystera, and molecular characterization, using the D2D3 expansion region of the 28S rDNA, which revealed a similarity of 99.99% with available sequences of the common spiral nematode H. dihystera. To our knowledge, M. javanica and H. dihystera are reported for the first time as parasitizing F. microcarpa. Our findings reveal that more inspections are required to detect these and other plant-parasitic nematodes, mainly with quarantine status, to prevent their spread if found.

First report of Meloidogyne graminicola on rice in Anhui province, China

Meloidogyne graminicola, a devastating plant pathogen of rice (Oryza sativa), is considered to a severe constraint to productivity in rice-growing areas (Zhan et al., 2018). In April 2020, irrigated paddy rice field in Qianshan City, Anhui Province, China, showed symptoms with stunting, thinning, chlorosis, and typical hook-shaped root tips. Females and egg masses of Meloidogyne sp. were found inside the cortex of the root galls, males were found in soil and roots. The morphological characteristics of females, males and second-stage juveniles (J2) were identified as described previously (Tian et al., 2017; Wang et al., 2017). The perineal pattern of the females (n=12) was dorsoventrally oval with low and round dorsal arches, with lateral fields obscure or absent. Most of the striae were smooth, and occasionally broken by short and irregular striae. Morphological measurements (mean±sd, range) of female nematodes (n=20) were body length (543.0±66.0 µm, 448.0-629.0 µm), stylet (11.6±1.9 µm, 7.9-14.2 µm), dorsal pharyngeal gland orifice to stylet base (DGO) (4.0±0.4 µm, 3.4-4.7 µm), vulval slit length (24.1±4.9 µm, 14.8-32.8 µm), vulval slit to anus distance (16.1±3.0 µm, 8.4-20.2 µm). The male nematodes were cylindroid, vermiform, and rounded tail, with the measurements (n=20) body length (1673.0±125 µm, 1346.0-1822.0 µm), stylet (15.5±0.8 µm, 14.0-17.1 µm), DGO (3.7±0.5 µm, 2.9-5.5 µm), and spicule (30.7±2.5 µm, 23.4-34.6 µm). The J2 were vermiform with a gradually tapering hyalines, its measurements (n=20) were body length (452.0±33.0 µm, 391.0-511.0 µm), stylet (13.4±0.8 µm, 12.0-15.2 µm), DGO (3.6±0.6 µm, 2.5-4.7 µm), tail length (72.1±5.2 µm, 59.8-84.8 µm) and hyaline tail terminus (21.7±2.5 µm, 18.0-29.7 µm). DNA extracted from individual females (n=10) were used for molecular identification. The D2/D3 region of 28S RNA was amplified with D2A (5'-ACA AGT ACC GTG AGG GAA AGT TG-3') and D3B (5'-TCG GAA GGA ACC AGC TAC TA-3') (De Ley et al. 1999). The ITS region was amplified with AB28 (5'-ATA TGC TTA AGT TCA GCG GGT-3') and TW81 (5'-GTT TCC GTA GGT GAA CCT GC-3') (Curran et al. 1994). The fragments of D2/D3 region (GenBank accession No. MT576694) and ITS region (GenBank accession No. MT573412) were 766 bp and 579 bp respectively, they all exhibited 99%-100% similarity with those of M. graminicola isolates available in the GenBank. Therefore, both morphological and molecular characterization confirmed the status of this nematode as Meloidogyne graminicola. In green house test, twenty 2-week-old rice seedlings (cv. Longliangyou) were individually maintained in pots with sterilized sand and soil (3:1) and inoculated with 300 J2, other ten non-inoculated rice seedlings as negative control. Rice seedlings were grown in green house at 28℃/25℃ with a 16 h/8 h light/dark photoperiod. After 30 days, all inoculated rice seedling showed symptoms with stunting, chlorosis, and typical hook-shaped root tips, which were similar with that in fields. The nematode reproduction index (final population density/initial population density) were 7.86-10.32. No symptoms were observed on non-inoculated rice seedlings. These results confirmed the pathogenicity of M. graminicola on rice. To our knowledge, this is the first report of M. graminicola in Anhui Province, China. References Curran, J., et al. 1994. Mycol. Res. 98:547. https://doi.org/10.1016/S0953-7562(09)80478-4. De Ley, P., et al. 1999. Nematology. 1:591. https://doi.org/10.1163/156854199508559. Tian, Z., et al. 2017. Plant Disease. http://dx.doi.org/10.1094/PDIS-06-17-0832-PDN. Wang, G., et al. 2017. Plant Disease. http://dx.doi.org/10.1094/PDIS-12-16-1805-PDN. Zhan, L., et al. 2018. BMC Plant Biol. 18:50. https://doi.org/10.1186/s12870-018-1266-9.

First report of Meloidogyne javanica infecting Zinnia elegans in Ceará State, Brazil

Roots of Zinnia elegans exhibiting galls were observed and collected in the city of Pacoti, CE, Brazil. Through the morphological characterization and molecular analysis of the ITS and 28S rDNA regions, the causal agent was identified as a nematode of the genus Meloidogyne species M. javanica. This is the first detection of M. javanica in Zinnia elegans in the state of Ceará in Brazil.

An integrative approach to the study of Helicotylenchus (Nematoda: Hoplolaimidae) Colombian and Brazilian populations associated with Musa crops

In total, 10 populations of Helicotylenchus associated with Musa spp., six from Colombia, and four from Brazil were identified to the species level. Morphological and morphometric data were recorded for each population, performed a principal components analysis (PCA), a conglomerate, along with consensus sequences of D2 to D3 expansion segment of the large subunit of ribosomal DNA (28S) for different populations. Identify of species were performed using the basic local alignment search tool (BLAST), and the evolutionary relationships of species were explored using a phylogeny study. Four species of Helicotylenchus were identified based on morphological and morphometric data: H. multicinctus, H. dihystera, H. erythrinae, and H. californicus. PCA and conglomerate analysis clearly separated these species. BLAST and phylogenetic analysis confirmed the presence of these species associated with Musa spp. crops. This is the first report of these species in Colombia through integrative taxonomy.

In total, 10 populations of Helicotylenchus associated with Musa spp., six from Colombia, and four from Brazil were identified to the species level. Morphological and morphometric data were recorded for each population, performed a principal components analysis (PCA), a conglomerate, along with consensus sequences of D2 to D3 expansion segment of the large subunit of ribosomal DNA (28S) for different populations. Identify of species were performed using the basic local alignment search tool (BLAST), and the evolutionary relationships of species were explored using a phylogeny study. Four species of Helicotylenchus were identified based on morphological and morphometric data: H. multicinctus, H. dihystera, H. erythrinae, and H. californicus. PCA and conglomerate analysis clearly separated these species. BLAST and phylogenetic analysis confirmed the presence of these species associated with Musa spp. crops. This is the first report of these species in Colombia through integrative taxonomy.

Distribution of trichodorid species in mainland China with description of Trichodorus hangzhouensis sp. nov. (Nematoda, Triplonchida)

Seven trichodorid species including a new one (Trichodorushangzhouensissp. nov., T.nanjingensis, T.pakistanensis, T.cedarus, Paratrichodorusporosus, Nanidorusrenifer and N.minor) were recovered from the rhizosphere of different hosts in 13 provinces of China. Each of the recovered species was characterized based on morphology and molecular data using rRNA gene sequences. Trichodorushangzhouensissp. nov. is characterized by its males having medium-sized onchiostyle (46–49 µm) and three ventromedian cervical papillae (CP) anterior to the secretory-excretory (S-E) pore, CP1 located opposite the anterior part of isthmus, S-E pore opposite the isthmus or anterior end of pharyngeal bulb, spicules slightly ventrally curved, relatively small, 33.2 (32.0–34.5) µm long, wider slightly marked capitulum, lamina partially striated without bristles at striation; and females having rounded triangular sclerotized vaginal pieces with tips directed towards vulva, 1.5–2.0 µm sized, at about 1 µm apart, vulva pore-like in ventral view. Phylogenetic analysis based on D2-D3 28S rRNA gene sequences differentiated the new species among Trichodorus species from Europe, Asia and USA which formed a large clade. A review of the distribution of Trichodorus, Nanidorus and Paratrichodorus species revealed that T.cedarus, T.nanjingensis, T.pakistanensis and P.porosus are the most widespread species recorded from different provinces of China. This is the first extensive study of trichodorid species occurring in China.

Incidence of the Rice Root-Knot Nematode, Meloidogyne graminicola, in Guangxi, China

Root-knot nematodes (Meloidogyne spp.) are the most destructive group of plant-parasitic nematodes. Plants infected by Meloidogyne spp. develop above-ground symptoms, stunting, yellowing, nutrient deficiencies, and gall formations with typical hook-shaped root tips. Infected plants experience yield losses. During 2018-2019 survey, leaf chlorosis rice plants were found in 206 fields of 67 counties in Guangxi, China, around 30 days after transplanting. Galls and hooked tips on the roots and pear-shaped females were observed. About 32.04% of fields were infested with the nematode. The nematodes were identified as Meloidogyne graminicola base on morphological and molecular analysis. To the best of our knowledge, this is the first report of M. graminicola on rice plants in Guangxi, China. The results of this study urge the discovery of resistant cultivars and the development of management strategies.

A new rare nematode Nothocriconemoides hangzhouensis n. sp. (Nematoda: Criconematidae) from Hangzhou, China

The Family Criconematidae is commonly referred as ring nematodes that include some members with economic importance as plant parasites. During a recent nematode inventory survey at Zhejiang Province, China, a new species of genus Nothocriconemoides was detected in the rhizosphere of elm tree. Nothocriconemoides hangzhouensis n. sp. can be characterized by the female body having annuli with fine longitudinal striations and 2 to 3 anastomoses at the posterior half of the body. The first cephalic annulus is rounded and expanded enclosing the lip region, and the second annulus is narrow, offset, collar like. En face view shows a central elevated labial disk bearing four distinct equal-sized submedian lobes and "I" shaped oral aperture. Excretory pore is located 3-4 annuli posterior to esophageal bulb. Vagina is straight and vulva closed. The ventral side of postvulval annuli is inverted, in majority of individuals. Anus is indistinct and located on the next annuli posterior to vulva. Tail is short, conoid, with forked or branched terminus. Juveniles are devoid of collar-shaped annuli in the lip region. The cephalic region has two rounded annuli where the first annulus shows slight depression in the middle. Body annuli are finely crenated. Anus is indistinct and located 3 to 4 annuli from tail terminus. Tail is short ending in a single lobed terminus. Phylogenetic studies based on analysis of the D2-D3 expansion segments of the 28 S rRNA, ITS rRNA, partial 18 S rRNA, and coxI gene revealed that the new species formed a separate clade from other criconematid species, thereby supporting its status as a new species of the genus. The new species showed close relationships with Discocriconemella sinensis. Additionally, this is the first record of genus Nothocriconemoides from China.

The Family Criconematidae is commonly referred as ring nematodes that include some members with economic importance as plant parasites. During a recent nematode inventory survey at Zhejiang Province, China, a new species of genus Nothocriconemoides was detected in the rhizosphere of elm tree. Nothocriconemoides hangzhouensis n. sp. can be characterized by the female body having annuli with fine longitudinal striations and 2 to 3 anastomoses at the posterior half of the body. The first cephalic annulus is rounded and expanded enclosing the lip region, and the second annulus is narrow, offset, collar like. En face view shows a central elevated labial disk bearing four distinct equal-sized submedian lobes and “I” shaped oral aperture. Excretory pore is located 3–4 annuli posterior to esophageal bulb. Vagina is straight and vulva closed. The ventral side of postvulval annuli is inverted, in majority of individuals. Anus is indistinct and located on the next annuli posterior to vulva. Tail is short, conoid, with forked or branched terminus. Juveniles are devoid of collar-shaped annuli in the lip region. The cephalic region has two rounded annuli where the first annulus shows slight depression in the middle. Body annuli are finely crenated. Anus is indistinct and located 3 to 4 annuli from tail terminus. Tail is short ending in a single lobed terminus. Phylogenetic studies based on analysis of the D2–D3 expansion segments of the 28 S rRNA, ITS rRNA, partial 18 S rRNA, and coxI gene revealed that the new species formed a separate clade from other criconematid species, thereby supporting its status as a new species of the genus. The new species showed close relationships with Discocriconemella sinensis. Additionally, this is the first record of genus Nothocriconemoides from China.

A new stunt nematode, Geocenamus chengi n. sp. (Nematoda: Merliniinae) in the rhizosphere of tea (Camellia sinensis) from Zhejiang Province, China

The tea plant is native to China; the country has the greatest tea production areas in the world. In an attempt to investigate the nematode biodiversity associated with the tea plantations of Hangzhou, Zhejiang Province, a population of stunt nematode was detected. This group of nematodes is comprised of migratory ecto-parasites of roots and can subsist on a variety of host plants. Therefore, the detected population was studied carefully using the integrative taxonomy approach and identified as a new species of genus Geocenamus. Geocenamus chengi n. sp. can be characterized by females having six incisures in the lateral field; labial region is dome shaped and slightly offset from the rest of the body having four to five annuli; head framework is weakly developed; deirids are absent; excretory pore is located at the anterior region of basal pharyngeal bulb. Under SEM, the vulva is a transverse slit, vulval lips are elongated and ellipsoidal with epiptygma. The tail is annulated, elongated, and conical having bluntly pointed tip and a terminal hyaline region that forms 21 to 33% of the tail length. Spicule is 22 to 25 μm long, gubernaculum is saucer shaped; bursa is crenated covering the tail until the hyaline tail region. Morphologically, the species is close to G. circellus, G. joctus, G. loofi, G. ordinarius, G. processus, G. tetyllus, and G. tortilis. Phylogenetic relationships of the new species based on D2-D3 expansion domains of 28 S, ITS, and 18 S rRNA genes indicated that G. chengi n. sp. clustered in a separate clade with G. vietnamensis.

The tea plant is native to China; the country has the greatest tea production areas in the world. In an attempt to investigate the nematode biodiversity associated with the tea plantations of Hangzhou, Zhejiang Province, a population of stunt nematode was detected. This group of nematodes is comprised of migratory ecto-parasites of roots and can subsist on a variety of host plants. Therefore, the detected population was studied carefully using the integrative taxonomy approach and identified as a new species of genus Geocenamus. Geocenamus chengi n. sp. can be characterized by females having six incisures in the lateral field; labial region is dome shaped and slightly offset from the rest of the body having four to five annuli; head framework is weakly developed; deirids are absent; excretory pore is located at the anterior region of basal pharyngeal bulb. Under SEM, the vulva is a transverse slit, vulval lips are elongated and ellipsoidal with epiptygma. The tail is annulated, elongated, and conical having bluntly pointed tip and a terminal hyaline region that forms 21 to 33% of the tail length. Spicule is 22 to 25 μm long, gubernaculum is saucer shaped; bursa is crenated covering the tail until the hyaline tail region. Morphologically, the species is close to G. circellus, G. joctus, G. loofi, G. ordinarius, G. processus, G. tetyllus, and G. tortilis. Phylogenetic relationships of the new species based on D2-D3 expansion domains of 28 S, ITS, and 18 S rRNA genes indicated that G. chengi n. sp. clustered in a separate clade with G. vietnamensis.