scholarly journals First Report of Catenaria auxiliaris Parasitizing the Reniform Nematode Rotylenchulus reniformis on Cotton in Alabama

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 490-490 ◽  
Author(s):  
J. D. Castillo ◽  
K. S. Lawrence
Keyword(s):  
Sandy Loam ◽  
Nematophagous Fungus ◽  
Life Stages ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
First Report ◽  
Resting Spores ◽  
Scanning Electron Micrography ◽  
Advanced Stages ◽  
Reniform Nematodes

A new fungal parasite of the reniform nematode has been observed parasitizing nematode populations that have increased on cotton in a sandy loam field soil in the greenhouse. When enumerated, 46% of the stock reniform nematode population was colonized by this fungus. Egg, vermiform, and adult stages of the reniform nematode were observed with light microscopy and scanning electron micrography (SEM). The nematophagous fungus, Catenaria auxiliaries, was identified morphologically. There are no sequences on the GenBank to achieve a molecular identification. This nematophagous fungus has been previously reported on the beet cyst nematode in Europe (1,2); however, to our knowledge there are no reports of this fungus parasitizing the reniform nematode. In vermiform life stages of the nematode, rhizomycelium is observed in the initial phase of infection and is characterized by ovoid cells, 9.5 to 13.5 × 17.0 to 24.5 μm in diameter, separated by septa. Usually 10 to 15 ovoid cells lacking intercellular hyphal filaments are produced within each vermiform body. Rhizoids 3.5 to 4.0 μm wide develop from the rhizomycelium. Mature swollen cells produce precursor sporangia that may mature into resting spores or zoosporangia. Resting spores are yellow-to-cream, 20 to 40 μm in diameter with a reticulate appearance, and are common in the vermiform nematode life stages. Zoosporangia are ovoid, 9.5 to 13.5 × 17.0 to 24.5 μm, and will erupt from the cuticle of the vermiform nematode releasing zoospores via papillae. Zoospores are 2.9 to 4.9 μm with visible globules in the anterior region and single flagella that are 9 to 11 μm long. The zoospores swim short distances, maneuvering in the direction of the flagellum. Adult reniform females observed through SEM exhibit zoospores encysted in the metacorpus region of the nematode. Parasitized eggs are internally colonized with zoosporangia that are 20 to 25 μm in diameter. In advanced stages of infection, the eggs darken in color and zoosporangia erupt through the cuticle of the egg. Reniform nematodes visibly colonized with zoosporangia and resting spores were placed on corn meal, water, and potato dextrose agars. None of these media supported growth of the fungus, supporting our theory that this organism appears to be an obligate parasite of the nematode. Koch's postulates was completed when eggs colonized with rhizomycelium and resting spores or zoosporangia were added to cotton plants in sterile soil previously inoculated with 2,000 healthy vermiform reniform life stages. Plants were allowed to grow for 30 days in the greenhouse after which the next generation of vermiform nematodes were extracted from the soil and examined under the microscope. Rhizomycelium, resting spores, and zoosporangia were present in 42% of the reniform vermiform life stages. Morphological comparisons of the rhizomycelium, resting spores or zoosporangia, and zoospores colonizing the reniform nematodes were similar to the initial observations. Thus to our knowledge, this is the first report of Catenaria auxiliaries parasitizing the reniform nematode. References: (1) B. Kerry. J. Nematol. 12:253, 1980. (2) H. T. Tribe. Trans. Br. Mycol. Soc. 69:367, 1977.

scholarly journals First Report of the Reniform Nematode (Rotylenchulus reniformis) from Soybean in Paraguay

Plant Disease ◽  
2018 ◽  
Vol 102 (10) ◽  
pp. 2043-2043
Author(s):  
H. D. Lopez-Nicora ◽  
L. M. Pedrozo ◽  
C. Grabowski Ocampos ◽  
A. L. Orrego Fuente ◽  
E. Hahn Villalba ◽  
...  
Keyword(s):  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
First Report

scholarly journals Conventional PCR Detection and Real-Time PCR Quantification of Reniform Nematodes

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1757-1762 ◽  
Author(s):  
Ronald J. Sayler ◽  
Courtney Walker ◽  
Fiona Goggin ◽  
Paula Agudelo ◽  
Terrence Kirkpatrick
Keyword(s):  
Real Time ◽  
Dna Sequences ◽  
Real Time Pcr ◽  
Its Region ◽  
Taqman Probe ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Conventional Pcr ◽  
Diagnostic Assays ◽  
Reniform Nematodes

Reniform nematode (Rotylenchulus reniformis) is a relatively recent introduction into the continental United States that can cause major yield losses on a variety of important crops including cotton and soybeans. DNA sequences from the internal transcribed spacer (ITS) region of this nematode were used to design primers for conventional and real-time PCR, as well as a TaqMan probe. These primers amplified DNA of reniform nematode isolates from a wide geographic range but did not detect genetically related species or other pathogenic nematodes found in production fields including Meloidogyne incognita and Heterodera glycines. Both SYBR green and TaqMan assays reliably quantified as little as 100 fg of reniform nematode DNA, and could be used to quantify as few as five reniform nematodes. An inexpensive and rapid DNA extraction protocol for high throughput diagnostic assays is described.

scholarly journals Cotton (Gossypium hirsutum) Cultivars Exhibiting Tolerance to the Reniform Nematode (Rotylenchulus reniformis)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Julie A. Blessitt ◽  
Salliana R. Stetina ◽  
Ted P. Wallace ◽  
Peggy T. Smith ◽  
Gabriel L. Sciumbato
Keyword(s):  
Gossypium Hirsutum ◽  
Field Study ◽  
Sandy Loam ◽  
Economic Losses ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Cotton Variety ◽  
Variety Trials ◽  
The Usa ◽  
Extension Center

A field study was conducted over a two-year period (2006-2007) at the Delta Research and Extension Center, Stoneville, MS, USA to screen selected entries in the 2006 Mississippi Cotton Variety Trials for tolerance to the reniform nematode (Rotylenchulus reniformis). Trials were conducted in nonirrigated fields with primarily sandy loam soils. Though some variability was noted between test locations and years, six of 13 cotton (Gossypium hirsutum) cultivars tested were considered tolerant to the reniform nematode: “Cropland Genetics 3520 B2RF,” “DynaGrow 2520 B2RF,” “Stoneville 5242 BR,” “Stoneville 5599 BR,” “Deltapine 488 BG/RR,” and “Fibermax 960 B2R.” Of these, the first three exhibited yields similar to the productive cultivar “Deltapine 445 BG/RR” in all environments. Though they will not suppress the reniform nematode population, these cultivars can help reduce economic losses attributed to this pathogen in the Midsouth region of the USA.

scholarly journals Resistance of soybean genotypes to the reniform nematode in a controlled environment

2013 ◽  
Vol 13 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Carlos Lasaro Pereira de Melo ◽  
Wanderléia Rodrigues dos Santos ◽  
Guilherme Lafourcade Asmus
Keyword(s):  
Artificial Inoculation ◽  
Controlled Environment ◽  
Western Region ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Randomized Design ◽  
Soybean Genotypes ◽  
Completely Randomized Design ◽  
Reniform Nematodes ◽  
Reproduction Factor

The aim of this study was to characterize the resistance to the reniform nematode of soybean genotypes derived from crosses with at least one parent resistant to Rotylenchulus reniformis or Heterodera glicynes, or to both. Two experiments in a greenhouse of Embrapa Western Region Agriculture, arranged in a completely randomized design, evaluated 199 genotypes with five replications. Sixty days after artificial inoculation (1000 eggs and larval forms), the nematodes were extracted from the roots and the genotypes evaluated for the number of eggs and larval forms per gram of root (NGR) and for the reproduction factor (RF). Sixty-five genotypes were resistant (RF <1.0), with mean RF significantly equal to M-SOY 8001. The highest number of lines resistant to reniform nematodes, in the different study combinations of crosses, were derived from the genotypes Custer, PI 437654, Fayette, BRSGO Ipameri, BRSMT Pintado, and BRS 262.

Sweet Potato Yield Reduction Caused by Reniform Nematode in the Mississippi Delta

2007 ◽  
Vol 8 (1) ◽  
pp. 2 ◽  
Author(s):  
Craig A. Abel ◽  
Larry C. Adams ◽  
Salliana R. Stetina
Keyword(s):  
Sweet Potato ◽  
Potato Production ◽  
Yield Reduction ◽  
Nematode Control ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Sweet Potatoes ◽  
Pronounced Difference ◽  
The Difference ◽  
Reniform Nematodes

A study was conducted to determine the effect of variable reniform nematode, Rotylenchulus reniformis Linford and Oliveira, population densities on sweet potato production. In 2003, post-harvest soil samples revealed that nematicide-treated plots had 1019 ± 257.2 reniform nematodes per 500 cm3 sample of soil compared to 2255 ± 383.3 for untreated plots. There were 1057 kg/ha more marketable sweet potato harvested from the nematicide-treated plots compared to the control. In 2004, there were fewer nematodes in the nematicide-treated plots at pre-planting, mid-season, and pre-harvest, with the most pronounced difference occurring at mid-season with 927 nematodes per 500 cm3 sample of soil in the nematicide untreated plots compared to 140 for the treated plots. The difference in nematode levels resulted in a 996-kg/ha increase in US #1 sweet potatoes harvested from nematicide-treated plots compared to the untreated plots. In 2005, two nematicides, K-PAM and Temik, were not different in their level of nematode control during the growing season, however, there was an increase in US #1 class sweet potatoes produced from the Temik-treated plots when compared to K-PAM. Both nematicide treatments produced more US #1 sweet potatoes when compared to a Lorsban control and an untreated control. Accepted for publication 13 September 2007. Published 15 November 2007.

Studies on life stages of reniform nematode, Rotylenchulus reniformis on papaya

2018 ◽  
Vol 26 (2) ◽  
pp. 365
Author(s):  
M. Sruthi ◽  
A. Shanthi ◽  
P. Vetrivelkalai ◽  
C. Kavitha
Keyword(s):  
Life Stages ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis

scholarly journals Quantitative Trait Loci Associated with Rotylenchulus reniformis Host Suitability in Soybean

2020 ◽  
Vol 110 (9) ◽  
pp. 1511-1521
Author(s):  
Juliet Wilkes ◽  
Christopher Saski ◽  
Mariola Klepadlo ◽  
Benjamin Fallen ◽  
Paula Agudelo
Keyword(s):  
Quantitative Trait Loci ◽  
Qtl Analysis ◽  
Quantitative Trait ◽  
The United States ◽  
Host Suitability ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Chromosome 18 ◽  
Nematode Reproduction ◽  
Trait Loci

Reniform nematode (Rotylenchulus reniformis) is a yield-limiting pathogen of soybean (Glycine max) in the southeastern region of the United States. A population of 250 recombinant inbred lines (RIL) (F2:8) developed from a cross between reniform nematode resistant soybean cultivar Forrest and susceptible cultivar Williams 82 was utilized to identify regions associated with host suitability. A genetic linkage map was constructed using single-nucleotide polymorphism markers generated by genotyping-by-sequencing. The phenotype was measured in the RIL population and resistance was characterized using normalized and transformed nematode reproduction indices in an optimal univariate cluster analysis. Quantitative trait loci (QTL) analysis using normalized phenotype scores identified two QTLs on each arm of chromosome 18 (rrn-1 and rrn-2). The same QTL analysis performed with log10(x) transformed phenotype data also identified two QTLs: one on chromosome 18 overlapping the same region in the other analysis (rrn-1), and one on chromosome 11 (rrn-3). While rrn-1 and rrn-3 have been reported associated with reduced reproduction of reniform nematode, this is the first report of the rrn-2 region associated with host suitability to reniform nematode. The resistant parent allele at rrn-2 showed an inverse relationship with the resistance phenotype, correlating with an increase in nematode reproduction or host suitability. Several candidate genes within these regions corresponded with host plant defense systems. Interestingly, a characteristic pathogen resistance gene with a leucine-rich repeat was discovered within rrn-2. These genetic markers can be used by soybean breeders in marker-assisted selection to develop lines with resistance to reniform nematode.

scholarly journals First report of Meloidogyne javanica pathogenic on hybrid lavender (Lavandula ×intermedia) in the United States

Plant Disease ◽  
2021 ◽  
Author(s):  
Samara A. Oliveira ◽  
Daniel M. Dlugos ◽  
Paula Agudelo ◽  
Steven N. Jeffers
Keyword(s):  
South Carolina ◽  
Sandy Loam ◽  
Meloidogyne Javanica ◽  
The United States ◽  
Crown Rot ◽  
Cultivated Plants ◽  
Broad Host Range ◽  
First Report ◽  
Tomato Roots ◽  
The Usa

Root-knot nematodes (RKNs), Meloidogyne spp., are some of the most economically important pathogens of cultivated plants. Meloidogyne javanica is one of the most destructive RKN species and is well known for its broad host range and the severe damage it causes to plant roots (Perry et al. 2009). In Feb 2018, four mature dead and dying hybrid lavender plants (Lavandula ×intermedia ‘Phenomenal’) were collected in Edgefield County, South Carolina, and suspected of having Phytophthora root and crown rot (Dlugos and Jeffers 2018). Greenhouse-grown plants had been transplanted in Dec 2016 and Jan 2017 into a sandy loam soil on a site that had been fallow or in pasture for over 30 years. Some plants began to turn gray and die in summer 2017, and approximately 40% of 1230 plants were symptomatic or dead by Feb 2018. Phytophthora spp. were not isolated from the collected plants but were isolated from plants collected on subsequent visits. Instead, all four plants had small, smooth galls on the roots. Lavender roots were examined microscopically (30-70×), and egg masses of RKNs were observed on the galls. Mature, sedentary RKN females were handpicked from galled roots, and perineal patterns of 10 specimens were examined and identified as M. javanica. Juveniles and eggs were extracted from lavender roots by the method of Coolen and D’herde (1972). To confirm species identification, DNA was extracted from 10 individual juveniles, and a PCR assay was conducted using species-specific primers for M. javanica, Fjav/Rjav (Zijlstra et al. 2000). A single amplicon was produced with the expected size of approximately 720 bp, which confirmed identity as M. javanica. To determine pathogenicity, M. javanica from lavender roots were inoculated onto susceptible tomato plants for multiplication, and severe gall symptoms occurred on tomato roots 60 days later. Nematodes were extracted from tomato roots and inoculated onto healthy, rooted cuttings of ‘Phenomenal’ lavender plants growing in pots of soilless medium in a greenhouse. Plants were inoculated with 0, 1000, 2000, 5000, or 10000 eggs and juveniles of M. javanica. Five single-plant replicates were used for each treatment, and plants were randomized on a greenhouse bench. Plants were assessed 60 days after inoculation, and nematodes were extracted from roots and counted. The reproduction factor was 0, 43.8, 40.9, 9.1, 7.7, and 2.6 for initial nematode populations 0, 1000, 2000, 5000, and 10000, respectively, which confirmed pathogenicity (Hussey and Janssen 2002). Meloidogyne javanica also was recovered in Mar 2018 from galled roots on a ‘Munstead’ (L. angustifolia) lavender plant from Kentucky (provided by the Univ. of Kentucky Plant Disease Diagnostic Laboratories), and an unidentified species of Meloidogyne was isolated in Aug 2020 from a ‘Phenomenal’ plant grown in Florida. COI mtDNA sequences from the SC (MZ542457) and KY (MZ542458) populations were submitted to Genbank. M. javanica previously was found associated with field-grown lavender (hybrid and L. angustifolia) in Brazil, but pathogenicity was not studied (Pauletti and Echeverrigaray 2002). To our knowledge, this is the first report of M. javanica pathogenic to L. ×intermedia in the USA, and the first time RKNs have been proven to be pathogenic to Lavandula spp. following Koch’s Postulates. Further studies are needed to investigate the geographic distribution of M. javanica on lavender and the potential threat this nematode poses to lavender production in the USA.

scholarly journals Cnidome and Morphological Features of Pelagia noctiluca (Cnidaria: Scyphozoa) Throughout the Different Life Cycle Stages

2021 ◽  
Vol 8 ◽  
Author(s):  
Ainara Ballesteros ◽  
Carina Östman ◽  
Andreu Santín ◽  
Macarena Marambio ◽  
Mridvika Narda ◽  
...  
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Later Life ◽  
Life Stages ◽  
Accurate Identification ◽  
Early Stages ◽  
Pelagia Noctiluca ◽  
Life Cycle Stages ◽  
Advanced Stages ◽  
Stage 1

Pelagia noctiluca is considered the most important jellyfish in the Mediterranean Sea, due to its abundance and the severity of its stings. Despite its importance in marine ecosystems and the health problems caused by its massive arrival in coastal areas, little is known about its early life stages and its cnidome has never been described. This study of the morphological and anatomical features throughout the life cycle identifies four early stages: two ephyra and two metaephyra stages. Ephyra stage 1, newly developed from a planula, has no velar canals, gastric filaments or nematocyst batteries. Ephyra stage 2, has velar canals, a cruciform-shaped manubrium and gastric filaments. Metaephyra stage 3 has eight tentacle buds and nematocyst clusters for the first time. Lastly, in metaephyra stage 4, the eight primary tentacles grow nearly simultaneously, with no secondary tentacles. Complete nematocyst battery patterns gradually develop throughout the later life stages. Four nematocyst types are identified: a-isorhiza, A-isorhiza, O-isorhiza and eurytele. Of these, a-isorhiza and eurytele are the most important throughout the entire life cycle, while A-isorhiza and O-isorhiza have a more important role in advanced stages. All nematocysts show a positive correlation between increasing capsule volumes and increasing body diameter of the ephyrae, metaephyrae, young medusae and adult medusae. In the early stages, the volumes of euryteles in the gastric filaments are larger than those in the exumbrella, indicating that the capsule volume is critical in the absence of marginal tentacles, specialized for feeding. This study provides updated information, the most extensive description to date, including high-resolution photographs and schematic drawings of all the developmental stages in the life cycle of P. noctiluca. Additionally, the first cnidome characterization is provided for each stage to facilitate accurate identification of this species when collected in the water column, and to raise awareness of the potential for human envenomation.

Root-knot and reniform nematodes: double trouble for soybeans in the southern United States.

2021 ◽  
pp. 125-131
Author(s):  
Edward J. Sikora
Keyword(s):  
United States ◽  
Life Cycle ◽  
Host Range ◽  
Geographical Distribution ◽  
Management Practices ◽  
Economic Importance ◽  
Southern United States ◽  
Rotylenchulus Reniformis ◽  
Future Outlook ◽  
Reniform Nematodes

Abstract This chapter focuses on the economic importance, host range, geographical distribution, symptoms of damage and biology and life cycle of root-knot and reniform nematodes (Meloidogyne spp. and Rotylenchulus reniformis) infesting soyabeans in southern USA. Some information on the efficacy and optimization of some recommended integrated nematode management practices and future outlook and research requirements are also presented.

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