First Detection of Ditylenchus destructor Parasitizing Maize in Northeast China

Maize is one of the most important crops in the world. Heilongjiang province has the largest maize area in China. Plant-parasitic nematodes are important agricultural pests, which cause huge economic losses every year and have attracted global attention. Potato rot nematode Ditylenchus destructor is a plant-parasitic nematode with a wide range of hosts and strong survival ability in different environments, which brings risks to agricultural production. In 2020, D. destructor was detected in seven maize fields in Heilongjiang province. Morphological identification and molecular approach were used to characterize the isolated D. destructor. The observed morphological and morphometric characteristics were highly similar and consistent with the existing description. The DNA sequencing on the D2/D3 region of the ribosomal DNA 28S and the phylogenetic analysis showed that D. destructor population obtained from maize and other isolates infesting carrot, sweet potato, and potato were in subclade I supported by a 96% bootstrap value. Additionally, the phylogenetic analysis of the ITS rRNA gene sequence further indicated that this D. destructor population from maize clustered in a clade I group and belonged to ITS rRNA haplotype C. An inoculation experiment revealed that D. destructor was pathogenic on the maize seedlings in pots and caused the disease symptoms in the stem base of maize seedlings. This is the first report of D. destructor causing stem rot of maize in Heilongjiang province, and contributes additional information on disease control and safe production of maize in the region.

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Morphological and molecular characterisation of several Paratylenchus Micoletzky, 1922 (Tylenchida: Paratylenchidae) species from South Africa and USA, together with some taxonomic notes

Nematology ◽

10.1163/15685411-00002769 ◽

2014 ◽

Vol 16 (3) ◽

pp. 323-358 ◽

Cited By ~ 17

Author(s):

Esther Van den Berg ◽

Louwrens R. Tiedt ◽

Esther Van den Berg ◽

Louwrens R. Tiedt ◽

...

Keyword(s):

South Africa ◽

Rrna Genes ◽

Morphological Identification ◽

Rrna Gene ◽

28S Rrna ◽

Molecular Characterisation ◽

Electron Microscopic ◽

Wide Range ◽

Its Rrna Gene ◽

Its Rrna

Pin nematodes of the genus Paratylenchus are widely distributed across the world and associated with many plant species. Morphological identification of Paratylenchus species is a difficult task because it relies on many characters with a wide range of intraspecific variation. In this study we provide morphological and molecular characterisation of several pin nematodes: Paratylenchus aquaticus, P. dianthus, P. hamatus, P. nanus and P. straeleni, collected in different states of the USA and South Africa. Paratylenchus aquaticus is reported from South Africa and Hawaii and P. nanus is found from South Africa for the first time. Morphological descriptions, morphometrics, light and scanning electron microscopic photos and drawings are given for these species. Molecular characterisation of nematodes using the D2-D3 of 28S rRNA and ITS rRNA gene sequence revealed that samples morphologically identified as P. aquaticus, P. hamatus and P. nanus indeed represent species complexes containing several species. Sequences of the rRNA genes are also provided for several unidentified Paratylenchus. Phylogenetic relationships within the genus Paratylenchus are given as inferred from the analyses of the D2-D3 of 28S rRNA and ITS rRNA gene sequences. We present here the most complete phylogenetic analysis of the genus.

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Streptomyces rhizophilus Causes Potato Common Scab Disease

Plant Disease ◽

10.1094/pdis-09-20-1902-re ◽

2021 ◽

Author(s):

Qi Wei ◽

Jie Li ◽

Shuai Yang ◽

Wenzhong Wang ◽

Fanxiang Min ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Common Scab ◽

Bacterial Species ◽

Economic Losses ◽

Pcr Analysis ◽

Rrna Gene ◽

Heilongjiang Province ◽

Epidemic Disease ◽

Genus Streptomyces

Common scab (CS) caused by Streptomyces spp. is a significant soilborne potato disease that results in tremendous economic losses globally. Identification of CS-associated species of the genus Streptomyces can enhance understanding of the genetic variation of these bacterial species and is necessary for the control of this epidemic disease. The present study isolated Streptomyces strain 6-2-1(1) from scabby potatoes in Keshan County, Heilongjiang Province, China. PCR analysis confirmed that the strain harbored the characteristic Streptomyces pathogenicity island (PAI) genes (txtA, txtAB, nec1, and tomA). Pathogenicity assays proved that the strain caused typical scab lesions on potato tuber surfaces and necrosis on radish seedlings and potato slices. Subsequently, the strain was systemically characterized at morphological, physiological, biochemical and phylogenetic levels. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 6-2-1(1) shared 99.86% sequence similarity with Streptomyces rhizophilus JR-41T, isolated initially from bamboo in rhizospheric soil in Korea. PCR amplification followed by Sanger sequencing of the 16S rRNA gene of 164 scabby potato samples collected in Heilongjiang Province from 2019 to 2020 demonstrated that approximately 2% of the tested samples were infected with S. rhizophilus. Taken together, these results demonstrate that S. rhizophilus is capable of causing potato CS disease and may pose a potential challenge to potato production in Heilongjiang Province of China.

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Synonymy of Afenestrata with Heterodera supported by phylogenetics with molecular and morphological characterisation of H. koreana comb. n. and H. orientalis comb. n. (Tylenchida: Heteroderidae)

Nematology ◽

10.1163/156854108785787190 ◽

2008 ◽

Vol 10 (5) ◽

pp. 611-632 ◽

Cited By ~ 12

Author(s):

Manuel Mundo-Ocampo ◽

Alberto Troccoli ◽

Sergei A. Subbotin ◽

Julio Del Cid ◽

James G. Baldwin ◽

...

Keyword(s):

Morphological Identification ◽

Rrna Gene ◽

Similar Species ◽

28S Rrna ◽

Diagnostic Pcr ◽

Second Stage ◽

Pcr Rflp ◽

Identification Of Species ◽

Its Rrna ◽

Labial Disc

Abstract Phylogenetic analysis of five gene fragments: ITS-rRNA, D2 and D3 of 28S rRNA, 18S rRNA, Hsp90 and actin, of Heterodera species and two representative Afenestrata species, A. koreana and A. orientalis, form a clade with H. cynodontis, H. bifenestra and an unidentified Heterodera sp. infecting grasses. Based on these results and the consideration that the key diagnostic characters of Afenestrata are convergent and do not define a clade, synonymisation of Afenestrata with Heterodera is proposed. The following new combinations are made: H. africana comb. n., H. axonopi comb. n., H. koreana comb. n., and H. orientalis comb. n. Furthermore, H. (= Afenestrata) sacchari is renamed as H. saccharophila nom. nov. to avoid homonymy. All these species, together with H. bamboosi, are regarded as members of a paraphyletic ‘Afenestrata group’ within Heterodera. Whilst recognised as artificial, the Afenestrata group is nevertheless an aid to discussion about these similar species. Morphological and molecular characterisation of populations of H. koreana comb. n. from Florida and H. orientalis comb. n. from Florida and Guatemala verify the identification of these populations as valid representatives for molecular studies of the species. Light and SEM observations also provide new detail and a broader understanding of the morphological range of both species. These include a longer stylet for females of H. koreana comb. n. and H. orientalis comb. n. than reported in the original descriptions. In addition, previously unreported tuberculate ridges are noted on the surface of vulval lips of H. orientalis comb. n. The lip region of second-stage juveniles of H. koreana comb. n. and H. orientalis comb. n. both include fused adjacent submedian lips that also fuse with the labial disc and the second lip annulus. The ITS-rRNA gene sequences of H. orientalis comb. n. populations from Florida and Guatemala were similar to those from the Russian type locality. Diagnostic PCR-RFLP of ITS-rRNA profiles with six enzymes for H. orientalis comb. n. and H. koreana comb. n. are given. A key for the morphological identification of species of the Afenestrata group is provided.

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Prevalence of Porcine Pseudorabies Virus and Its Coinfection Rate in Heilongjiang Province in China from 2013 to 2018

10.21203/rs.2.12447/v1 ◽

2019 ◽

Author(s):

Han Zhou ◽

Yan Pan ◽

Mengda Liu ◽

Zifeng Han

Keyword(s):

Pseudorabies Virus ◽

Classical Swine Fever ◽

Porcine Circovirus ◽

Economic Losses ◽

Respiratory Syndrome Virus ◽

Heilongjiang Province ◽

Serum Samples ◽

Tissue Samples ◽

Wide Range ◽

Pig Farms

Abstract Background Pseudorabies (PR) is a highly contagious disease affecting a wide range of animals worldwide, which causes great annual economic losses in China. In this study, a total number of 18815 serum samples and 1589 tissue samples were tested by ELISA and PCR, which were collected from 311 intensive pig farms (≥350 sows) located in eight cities in Heilongjiang province. Results Overall, 16.3% and 84.5% serum samples were positive for gE- and gB-specified ELISA, respectively. 17.8% of tissue samples were shown as PCR positive for PRV. The co-infection rates of PRV with porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), and classical swine fever virus (CSFV) were measured. The rate of PRV co-infected with PRRSV was 36.0% followed by 12.9% with PCV2 and 1.8% with CSFV, respectively. Conclusions These results clearly demonstrate PRV prevalence and its coinfection rate in Heilongjiang province indicating high PR endemic in pig farms in this region. This study provides data for further epidemiological investigations and a reference for developing PRV control strategies in this region and in China.

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Microenvironmental Conditions Drive the Differential Cyanobacterial Community Composition of Biocrusts from the Sahara Desert

Microorganisms ◽

10.3390/microorganisms9030487 ◽

2021 ◽

Vol 9 (3) ◽

pp. 487

Author(s):

Smail Mehda ◽

Maria Ángeles Muñoz-Martín ◽

Mabrouka Oustani ◽

Baelhadj Hamdi-Aïssa ◽

Elvira Perona ◽

...

Keyword(s):

Community Composition ◽

Salt Lake ◽

Extreme Environments ◽

Morphological Identification ◽

Rrna Gene ◽

Sahara Desert ◽

Cyanobacterial Community ◽

Unique Challenge ◽

Wide Range ◽

Bare Soils

The Sahara Desert is characterized by extreme environmental conditions, which are a unique challenge for life. Cyanobacteria are key players in the colonization of bare soils and form assemblages with other microorganisms in the top millimetres, establishing biological soil crusts (biocrusts) that cover most soil surfaces in deserts, which have important roles in the functioning of drylands. However, knowledge of biocrusts from these extreme environments is limited. Therefore, to study cyanobacterial community composition in biocrusts from the Sahara Desert, we utilized a combination of methodologies in which taxonomic assignation, for next-generation sequencing of soil samples, was based on phylogenetic analysis (16S rRNA gene) in parallel with morphological identification of cyanobacteria in natural samples and isolates from certain locations. Two close locations that differed in microenvironmental conditions were analysed. One was a dry salt lake (a “chott”), and the other was an extension of sandy, slightly saline soil. Differences in cyanobacterial composition between the sites were found, with a clear dominance of Microcoleus spp. in the less saline site, while the chott presented a high abundance of heterocystous cyanobacteria as well as the filamentous non-heterocystous Pseudophormidium sp. and the unicellular cf. Acaryochloris. The cyanobacteria found in our study area, such as Microcoleus steenstrupii, Microcoleus vaginatus, Scytonema hyalinum, Tolypothrix distorta, and Calothrix sp., are also widely distributed in other geographic locations around the world, where the conditions are less severe. Our results, therefore, indicated that some cyanobacteria can cope with polyextreme conditions, as confirmed by bioassays, and can be considered extremotolerant, being able to live in a wide range of conditions.

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First Report of the Giant Stem Nematode, Ditylenchus gigas, from Broad Bean in Iran

Plant Disease ◽

10.1094/pdis-01-13-0069-pdn ◽

2013 ◽

Vol 97 (7) ◽

pp. 1005-1005 ◽

Cited By ~ 2

Author(s):

Z. Tanha Maafi ◽

Z. Majd Taheri ◽

S. A. Subbotin

Keyword(s):

Broad Bean ◽

Morphological Identification ◽

Rrna Gene ◽

28S Rrna ◽

African Countries ◽

First Report ◽

28S Rrna Gene ◽

The North ◽

Plant Samples ◽

Its Rrna

The giant stem nematode, Ditylenchus gigas (Nematoda: Tylenchida) has been recorded from several European and African countries mainly bordering the Mediterranean Sea (2). This nematode causes considerable yield loss of broad bean, Vicia faba, and it may induce more severe damage than the typical faba bean race of D. dipsaci. Spread of infestation through seed limits export of broad bean and has made these nematodes quarantine pests in many countries (2). Broad bean is cultivated in the north, west, southwest, and central parts of Iran. Although D. dipsaci has been reported from different crops and regions in Iran, there is no record of broad bean infection by this nematode. A survey of broad bean fields was conducted in the north and west provinces in a continuation of a study on different populations of D. dipsaci in Iran in May to July of 2007 and 2008 and resampling from some farms in June 2012. The sampling was performed at flowering stage and after. The aboveground plant samples were collected and cut into pieces of 2 to 3 cm, then incubated for 5 to 6 h in Whitehead trays. Morphological and molecular analysis of isolated nematodes from Kermanshah and Lorestan provinces revealed the presence of D. gigas in the samples. Of the 23 plant samples of cv. Barekat collected from Mazandaran and Golestan provinces in the north, 47.8% were infected with stem nematode, mostly with high population density of over 20,000 nematodes per 5 plant stems. The percentage of infected samples of broad bean cv. Shakhbozy collected in Lorestan and Kermanshah provinces in the west was 76.5%. The symptoms of infection were observed as necrotic lesions on the stem surface and reduction of internode distances in severe infection. The giant stem nematode population from Kermanshah showed the following characters: females (n = 20), L = 1,650 ± 140 (1,270 to 1,875) μm; b′ = 8.6 ± 0.6 (7.7 to 10.0), c = 19.0 ± 1.3 (19.2 to 21.2), c′ = 4.7 ± 0.5 (1.1 to 5.3), stylet = 11.6 ± 0.5 (11 to 12) μm; post vulval sac = 96 ± 16 (58 to 140) μm; vulval-anus distance = 217.0 ± 21.0 (178 to 272) μm, tail = 86.4 ± 9.4 (66 to 102) μm; males (n = 10), L = 1,495 ± 148 (1,236 to 1,636) μm; b′ = 7.7 ± 0.3 (7.3 to 8.1), c = 17.3 ± 0.7 (16.3 to 18.6), stylet = 11.3 ± 0.5 (11 to 12) μm, tail = 86.5 ± 8.5 (71 to 95) μm, spicules = 24.8 ± 1.7 (23 to 28) μm. The morphological and morpohometric features were generally in agreement with those published for D. gigas (2). The morphological identification of D. gigas from Iran was supported by the analyses of the ITS rRNA and the D2-D3 expansion segments of the 28S rRNA gene sequences. The rRNA gene of D. gigas from broad bean and D. dipsaci from garlic were amplified and sequenced using two primer sets: (i) the TW81 and AB28 for the ITS-rRNA and (ii) D2A and D3B for partly 28S rRNA gene, as described by (2). New sequences were deposited in the GenBank under accession numbers KC310732 through KC310735. The Iranian D. gigas sequences showed 100% similarity with those of the Italian D. gigas isolates (ITS rRNA: HQ219231, HQ219232; D2-D3 of 28S rRNA: HQ219217 and HQ219216). The identification was further supported by PCR with species specific SCAR (sequence characterized amplified region) primers for this species (1). The specimens from broad bean generated a specific fragment ∼200 bp for D. gigas, whereas the samples with D. dipsaci from garlic and alfalfa produced one fragment ∼250 bp specific for this species. To our knowledge, this is the first report of D. gigas from broad bean in Iran. References: (1) M. Esquibet et al. Genome 46:1077, 2003. (2) N. Vovlas et al. Plant Pathol. 60:762, 2011.

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Length variation and repetitive sequences of Internal Transcribed Spacer of ribosomal RNA gene, diagnostics and relationships of populations of potato rot nematode, Ditylenchus destructor Thorne, 1945 (Tylenchida: Anguinidae)

Nematology ◽

10.1163/138855410x551923 ◽

2011 ◽

Vol 13 (7) ◽

pp. 773-785 ◽

Cited By ~ 14

Author(s):

Sergei A. Subbotin ◽

Abbas Mohammad Deimi ◽

Jingwu Zheng ◽

Vladimir N. Chizhov

Keyword(s):

Phylogenetic Analyses ◽

Repetitive Sequences ◽

Repetitive Elements ◽

Rrna Gene ◽

Length Variation ◽

28S Rrna ◽

Gene Sequences ◽

Its Rrna Gene ◽

Its Rrna ◽

Ditylenchus Destructor

Abstract Seventy-eight ITS rRNA gene sequences obtained from the potato rot nematode, Ditylenchus destructor, collected across the world from different hosts were compared and analysed. The ITS rRNA gene sequences showed significant length variation between populations. The differences in this rRNA fragment length were due to the presence of repetitive elements in the ITS1, which were characterised by relatively higher rates of substitution changes. Reconstruction of secondary structure for the ITS1 revealed that these minisatellites formed a stem structure. Phylogenetic analyses of ITS rRNA and D2-D3 expansion segments of 28S rRNA gene sequences showed that all studied populations clustered in two major clades: a group of populations having the ITS sequences with the repetitive elements and a group of populations without the repetitive elements in the ITS. We propose to distinguish seven ITS rRNA haplotypes within potato rot nematode populations. PCR-ITS-RFLP diagnostic profiles are presented for these ITS haplotypes and usefulness of recently developed PCR methods with species-specific primers for D. destructor are analysed and discussed.

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Diagnosis of potato rot nematode Ditylenchus destructor using PCR-RFLP

RUDN Journal of Agronomy and Animal Industries ◽

10.22363/2312-797x-2020-15-4-353-362 ◽

2020 ◽

Vol 15 (4) ◽

pp. 353-362

Author(s):

Niloufar Mahmoudi ◽

Elena N. Pakina ◽

Liudmila A. Limantceva ◽

Anton V. Ivanov

Keyword(s):

Dna Sequences ◽

Molecular Taxonomy ◽

Parasitic Nematodes ◽

Its2 Region ◽

Rrna Gene ◽

Rdna Sequences ◽

Pcr Product ◽

Pcr Rflp ◽

Its Rrna ◽

Ditylenchus Destructor

During an investigation of nematodes in the Moscow region of Russia in 2019, a known species Ditylenchus destructor was recovered from tubers of potato plants. The genus Destructor is one of the most problematic genera of plant-parasitic nematodes. The numerous species reported for this genus have been cited from various sources. Due to the morphological similarity of many species and the lack of separation characteristics, the identification of D. destructor is difficult. Molecular taxonomy and phylogeny were used to confirm the identification. In the current study, PCR-RFLP illustrative models for the amplification of the ITS-rRNA gene were provided with two enzymes that could recognize D. destructor in potato tubers. Analysis of the rDNA sequences spanning both ITS1-ITS2 regions was carried out on the collected populations. The digestion of the PCR product of the ITS1-5.8S-ITS2 region with the enzyme TaqI produced three fragments; 100, 190, 550, and with Tru1I, two fragments were produced; 300 and 480 bp. The obtained DNA sequences were compared with those DNA sequences deposited in GenBank of populations isolated in other countries. The results showed no distinction between populations isolated from different host plant species, including populations found in the Russian Federation. New sequences from ITS-rRNA were deposited in the GenBank under accession number MN122076, MN658597, MN658599, MN658637, MN658638.

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Theileria ovis (Piroplasmida: Theileriidae) Detected in Melophagus ovinus (Diptera: Hippoboscoidea) and Ornithodoros lahorensis (Ixodida: Argasidae) Removed From Sheep in Xinjiang, China

Journal of Medical Entomology ◽

10.1093/jme/tjz193 ◽

2019 ◽

Vol 57 (2) ◽

pp. 631-635 ◽

Cited By ~ 1

Author(s):

Li Zhao ◽

Jinling Wang ◽

Yulin Ding ◽

Kairui Li ◽

Bo He ◽

...

Keyword(s):

18S Rrna ◽

18S Rrna Gene ◽

Economic Losses ◽

Rrna Gene ◽

Protozoan Parasites ◽

Autonomous Region ◽

Apicomplexan Parasites ◽

Wide Range ◽

Melophagus Ovinus ◽

Theileria Spp

Abstract Theileria spp. are tick-transmitted, intracellular apicomplexan protozoan parasites that infect a wide range of animals and, as such, can cause significant economic losses. The aim of the present study was to detect and analyze apicomplexan parasites from two different ectoparasites that were collected from Xinjiang Uygur Autonomous Region, China. The PCR-based detection of 18S rRNA indicated that Ornithodoros lahorensis specimens from Kashgar, Xinjiang, and Aksu were positive for Theileria spp., as were Melophagus ovinus specimens from Aksu. Meanwhile, phylogenetic analysis, based on the 18S rRNA gene sequences, revealed that the four amplified Theileria sequences could be attributed to T. ovis. To the best of our knowledge, this is the first study to report the detection of T. ovis DNA in M. ovinus and the first molecular identification study to confirm the detection of T. ovis in O. lahorensis in China. Accordingly, the present study extends the known distribution of T. ovis.

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DNA barcoding, phylogeny and phylogeography of the cyst nematode species from the genus Globodera (Tylenchida: Heteroderidae)

Nematology ◽

10.1163/15685411-00003305 ◽

2020 ◽

Vol 22 (3) ◽

pp. 269-297 ◽

Cited By ~ 3

Author(s):

Sergei A. Subbotin ◽

Javier Franco ◽

Rinus Knoetze ◽

Tatiana V. Roubtsova ◽

Richard M. Bostock ◽

...

Keyword(s):

Dna Barcoding ◽

Phylogenetic Analyses ◽

Economic Losses ◽

Rrna Gene ◽

Undescribed Species ◽

Gene Sequences ◽

Cyst Nematodes ◽

Isolated Populations ◽

The World ◽

Its Rrna

Summary Globodera presently contains 13 valid and three as yet undescribed species. Three species, G. rostochiensis, G. pallida and G. ellingtonae, the potato cyst nematodes (PCN), cause significant economic losses on potatoes around the world. In our study we provide comprehensive phylogenetic analyses of 455 ITS rRNA, 219 COI and 164 cytb gene sequences of 11 valid and two undescribed species of Globodera using Bayesian inference, maximum likelihood and statistical parsimony. New 205 COI, 116 cytb and 21 ITS rRNA gene sequences were obtained from 148 populations of these species collected from 23 countries. The phylogenetic analysis revealed that Globodera displayed two main clades in the trees: i) Globodera from South and North America parasitising plants from Solanaceae; and ii) Globodera from Africa, Europe, Asia and New Zealand parasitising plants from Asteraceae and other families. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it is hypothesised that Globodera species originated and diversified from several centres of speciation located in mountain regions and then dispersed across the world from these regions during the Pleistocene. High genetic diversity of Bolivian populations of G. rostochiensis was observed for both mtDNA genes. Analysis of phylogenetic relationships of G. pallida and G. rostochiensis populations revealed incongruence in topology between networks inferred from mtDNA genes, which might be an indication of possible recombination and selective introgression events through gene flow between previously isolated populations. This puts some limitations on the use of the mtDNA marker as universal DNA barcoding identifier for PCN. Globodera bravoae syn. n. is proposed as a junior synonym of G. mexicana.

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