First report of Meloidogyne javanica (Nematoda: Meloidogynidae) infecting Scoparia dulcis, a medicinal plant in Brazil.
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ABSTRACT:
SUBMITTER: Belle C
PROVIDER: S-EPMC6909385 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Root-knot nematodes (Meloidogyne spp.) infect a large number of crops including guava. We investigated a population of Meloidogyne sp. infecting guava in the Coimbatore region of Tamil Nadu, India for identification and species confirmation. Detailed morphological and morphometric observations based on second-stage juveniles, males, females, and perineal patterns showed resemblance of the isolated population with the original and subsequent descriptions of M. enterolobii. Isozyme analysis of the young egg-laying females displayed the characteristic esterase phenotype pattern similar to that of M. enterolobii. Additionally, the identity of the nematode population was further validated by M. enterolobii specific SCAR marker and ITS rDNA. Recently published reports on the occurrence and morphological descriptions of M. enterolobii from India are largely incongruent with the original and subsequent redescriptions of the species. Here, we present the most comprehensive morphology and morphometrics of an Indian population of M. enterolobii for its authentic identification.
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Project description: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.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.
| S-EPMC8015276 | biostudies-literature
Project description:Meloidogyne polycephannulata n. sp. is described from specimens collected from an area cultivated with carrot cv. Brasilia, in the city of Rio Paranaíba, in the region of Alto Paranaíba, Minas Gerais State, Brazil. The perineal pattern of the female is circular to ovoid with a high dorsal arch that has widely spaced, coarse annulations. The lateral field may have a deep furrow separating the dorsal and ventral arches. The medial lips are short and wide, whereas the lateral lips are large and triangular. The female stylet is 15-16 ?m long with wide knobs, distinctly divided by an indentation in the center. Its tip is slightly curved dorsally. The excretory pore opens 34-65 ?m from the anterior end. Females retain eggs and second-stage juveniles in their body cavity, similar to that of the cyst-forming nematodes. Males are 1.3-1.7 mm long and have a high head cap that is rounded and slopes posteriorly. The labial disc is fused to the medial lips. The head region has several irregular annulations that are similar in appearance to the first or second body annules that are likewise irregular, making the head region appear to be extremely large. The stylet of the male is 21-24 ?m long; it is slender, and has small, rounded knobs, that are distinctly indented medially and appear heart-shaped. The shaft has several tiny projections throughout its length. Mean second-stage juvenile length is 411.7 ?m. The juvenile head cap is elevated, the medial lips are small, and the lateral lips are elongate to triangular-shaped. The head region has several short, incomplete and irregular transverse annulations. The juvenile stylet is 14-23 ?m long with small, rounded, and sloping knobs. The thin tail ends with a short hyaline portion that is variable in size (16-26 ?m) and with a small, rounded tip. Isozyme profiles of esterases from Meloidogyne javanica show 3 strong bands (SB) at Rm 46, 59, and 66; profiles of M. polycephannulata n. sp. show a SB at Rm 47 and a weak band (WB) at Rm 52; M. petuniae has two SB at Rm 44 and 53; M. phaseoli has a SB at 53, 58, and 64 Rm; M. brasilensis has three SB at Rm 40, 58, and 66 and a WB at Rm 71; M. pisi has a SB at Rm 40, 60, and 64 and two WB at 46 and 50 Rm. Data from sequencing the 18S rDNA region of M. polycephannulata n. sp. confirms that it is different from M. arabicida, M. arenaria, M. ethiopica, M. incognita, M. javanica, M. paranaensis, and M. thailandica. Sequence identity among these eight species ranged between 85 to 93.4%. Meloidogyne polycephannulata n. sp. reproduces very well on carrot and tomato; poorly on pepper; and not at all on cotton, peanut, tobacco, watermelon, and sweet corn.
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Project description:Meloidogyne christiei isolated from turkey oak, Quercus laevies, from the type locality in Florida was characterized using isozyme profiles and ribosomal and mitochondrial gene sequences. The phenotype N1a detected from a single egg-laying female of M. christiei showed one very strong band of malate dehydrogenase (MDH) activity; however, no esterase (EST) activity was identified from macerate of one or even 20 females per well. Phylogenetic relationships within the genus Meloidogyne as inferred from Bayesian analysis of partial 18S ribosomal RNA (rRNA), D2-D3 of 28S rRNA, internal transcribed spacer (ITS) rRNA, and cytochrome oxidase subunit II (COII)-16S rRNA of mitochondrial DNA (mtDNA) gene fragments showed that M. christiei formed a separate lineage within the crown group of Meloidogyne and its relationships with any of three Meloidogyne clades were not resolved.
| S-EPMC4612186 | biostudies-literature
Project description:A high number of second stage juveniles of the root-knot nematode were recovered from soil samples collected from a corn field, located in Pickens County, South Carolina, USA in 2019. Extracted nematodes were examined morphologically and molecularly for species identification which indicated that the specimens of root knot juveniles were Meloidogyne hispanica. The morphological examination and morphometric details from second-stage juveniles were consistent with the original description and redescriptions of this species. The ITS rRNA, D2-D3 expansion segments of 28S rRNA, intergenic COII-16S region, nad5 and COI gene sequences were obtained from the South Carolina population of M. hispanica. Phylogenetic analysis of the intergenic COII-16S region of mtDNA gene sequence alignment using statistical parsimony showed that the South Carolina population clustered with Meloidogyne hispanica from Portugal and Australia. To our best knowledge, this finding represents the first report of Meloidogyne hispanica in the USA and North America.
| S-EPMC8634290 | biostudies-literature
Project description:Chenopodium album plants showing symptoms caused by root-knot nematodes were detected in the La Joya, Arequipa, Peru. Based on the morphological, esterase phenotypes, and molecular analyses of the mitochondrial DNA region between the cytochome oxidase subunit II and 16S rRNA genes (mtDNA) and species-specific characterized amplified region, the causal agent of the observed symptoms was identified as Meloidogyne incognita. Pathogenicity was confirmed by fulfilling a modified version of Koch's postulates. To our knowledge, this is the first report of M. incognita parasitizing C. album in Peru.
| S-EPMC8015282 | biostudies-literature
Project description:High infection rates of roots of wild kiwifruit (Actinidia chinensis Planch) and soil infestation by a root-knot nematode were found in Anshun, GuiZhou Province, China. Morphology, esterase phenotype and molecular analyses confirmed that this nematode was different from previously described root-knot nematodes. In this report, the species is described, illustrated and named Meloidogyne aberrans sp. nov. The new species has a unique combination of characters. A prominent posterior protuberance, round and faint perineal pattern and a medium-length stylet (13.6-15.5 ?m) characterized the females. Second-stage juveniles (J2) were characterized by a smooth lip region with distinctly protruded medial lips and a depression in outline at the oral aperture, a relatively long stylet (15.9-16.8 ?m), four incisures in the lateral field and a very short, even poorly defined, hyaline tail terminus (2.2-5.5 ?m). More incisures (11-15) existed in the lateral field of males, and the stylet and spicules of males were 18.2-19.6 ?m and 22.7-36.8 ?m long respectively. Egg masses were typically produced within the roots of kiwifruit. The new species had a rare Est phenotype, S2. Phylogenetic trees inferred from SSU, LSU D2D3, ITS, and partial coxII-16S rRNA revealed that M. aberrans sp. nov. was within the Meloidogyne clade and was distinguished from all described root-knot nematodes. Moreover, from histopathological observations, M. aberrans sp. nov. induced the formation of multinucleate giant cells.
| S-EPMC5576651 | biostudies-literature
Project description:Potato is the third most important crop in the world after rice and wheat, with a great social and economic importance in Portugal as it is grown throughout the country, including the archipelagos of Madeira and the Azores. The tropical root-knot nematode (RKN) Meloidogyne luci is a polyphagous species with many of its host plants having economic importance and the ability to survive in temperate regions, which pose a risk to agricultural production. In 2019, M. luci was detected from soil samples collected from the council of Santo António in Pico Island (Azores). Bioassays were carried out to obtain females, egg masses, and second-stage juveniles to characterize this isolate morphologically, biochemically, and molecularly. The observed morphological features and morphometrics showed high similarity and consistency with previous descriptions. Concerning the biochemical characterization, the esterase (EST) phenotype displayed a pattern with three bands similar to the one previously described for M. luci and distinct from M. ethiopica. Regarding the molecular analysis, an 1800 bp region of the mitochondrial DNA between cytochrome oxidase subunit II (COII) and 16S rRNA genes was analyzed and the phylogenetic tree revealed that the isolate grouped with M. luci isolates (99.17%). This is the first report of M. luci parasitizing potato in the Azores islands, contributing additional information on the distribution of this plant-parasitic nematode.
| S-EPMC7825027 | biostudies-literature
Project description: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.
| S-EPMC7857618 | biostudies-literature
Project description:The root-knot nematode Meloidogyne ulmi is synonymised with Meloidogyne mali based on morphological and morphometric similarities, common hosts, as well as biochemical similarities at both protein and DNA levels. M. mali was first described in Japan on Malus prunifolia Borkh.; and M. ulmi in Italy on Ulmus chenmoui W.C. Cheng. Morphological and morphometric studies of their holo- and paratypes revealed important similarities in the major characters as well as some general variability in a few others. Host test also showed that besides the two species being able to parasitize the type hosts of the other, they share some other common hosts. Our study of the esterase and malate dehydrogenase isozyme phenotypes of some M. ulmi populations gave a perfectly comparable result to that already known for M. mali. Finally, phylogenetic studies of their SSU and LSU rDNA sequence data revealed that the two are not distinguishable at DNA level. All these put together, leave strong evidences to support the fact that M. ulmi is not a valid species, but a junior synonym of M. mali. Brief discussion on the biology and life cycle of M. mali is given. An overview of all known hosts and the possible distribution of M. mali in Europe are also presented.
| S-EPMC3867104 | biostudies-literature