reniform nematode

Reniform nematodes of the genus Rotylenchulus are semiendoparasites of numerous herbaceous and woody plant roots and occur largely in regions with temperate, subtropical and tropical climates. In this study, we provide new records of the nematode R. 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 it has previously been 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, wild and cultivated olive)...

Reniform nematode (Rotylenchulus reniformis Linford and Oliveira) is a yield-limiting pathogen of soybean (Glycine max (L.) Merrill) in the southeastern region of the United States. A population of 250 recombinant inbred lines (RIL)(F7:8) 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...

Plant-parasitic nematodes ( Rotylenchulus reniformis (reniform, RN), Helicotylenchus dihystera (spiral), and Mesocriconema ornatum (ring)) and yield were investigated in cotton phases of conventional (peanut-cotton-cotton) and sod-based (bahiagrass-bahiagrass-peanut-cotton) rotations with or without irrigation and fluopyram nematicide at a long-term research site, established in 2000, in Quincy, Florida, USA. Objectives were to determine impacts of nematicide application on cotton yield and evaluate effects of nematicide on plant-parasitic nematodes in these rotations in 2017 and 2018...

Cotton is an important crop that has made significant gains in production over the last century. Emerging pests such as the reniform nematode have threatened cotton production. The rare African diploid species Gossypium longicalyx is a wild species that has been used as an important source of reniform nematode immunity. While mapping and breeding efforts have made some strides in transferring this immunity to the cultivated polyploid species, the complexities of interploidal transfer combined with substantial linkage drag have inhibited progress in this area...

This study employed single nucleotide polymorphisms (SNPs) to determine the genetic variability present in 26 isolates of Rotylenchulus reniformis from Louisiana, Mississippi, Arkansas, South Carolina, Georgia, Hawaii, and Alabama. Genomic DNA from reniform nematode was extracted and increased quantitatively using the process of whole genome amplification. More than 162 putative SNPs were identified, 31 of which were tested using a KASP kompetitive allele-specific PCR genotyping assay. Of the SNPs tested, 13, 17, and 19 SNPs revealed genetic variability within reniform nematode isolates from Louisiana, Mississippi, and Arkansas, respectively...

A rapid non-destructive reniform nematode (Rotylenchulus reniformis) screening protocol is needed for the development of resistant cotton (Gossypium hirsutum) varieties to improve nematode management. Most protocols involve extracting vermiform nematodes or eggs from the cotton root system or potting soil to determine population density or reproduction rate. These approaches are generally time-consuming with a small number of genotypes evaluated. An alternative approach is described here in which the root system is visually examined for nematode infection...

The in vitro growth of Ganoderma mycelia on six agro-wastes namely, broad bean stalks (BBS), cotton stalk (CS), maize straw (MS), rice straw (RS), sugarcane bagasse (SCB) and wheat straw (WS) supplemented with wheat bran (WB) or corn gluten (CG) was evaluated. Among the substrates used, CS appeared best followed by SCB and RS. WB showed best supplementation for mycelial growth. CO2 emission values exhibited accurate measurements to decide the suitability of such agro-waste for growth rather than visual observations...

BACKGROUND: Reniform nematode (Rotylenchulus reniformis) has emerged as one of the most destructive root pathogens of upland cotton (Gossypium hirsutum) in the United States. Management of R. reniformis has been hindered by the lack of resistant G. hirsutum cultivars; however, resistance has been frequently identified in germplasm accessions from the G. arboreum collection. To determine the genetic basis of reniform nematode resistance, a genome-wide association study (GWAS) was performed using 246 G...

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The reniform nematode (Rotylenchulus reniformis Linford and Oliveira) has emerged as the most important plant-parasitic nematode of cotton in the United States cotton belt. Success in the development of reniform nematode-resistant upland cotton cultivars (Gossypium hirsutum L.) has not been realized despite over three decades of breeding efforts. Research approaches ranging from conventional breeding to triple species hybrids to marker-assisted selection have been employed to introgress reniform nematode resistance from other species of cotton into upland cultivars...

The semi-endoparastic reniform nematode (Rotylenchulus reniformis) infects over 300 plant species. Females penetrate host roots and induce formation of complex, multinucleate feeding sites called syncytia. While anatomical changes associated with reniform nematode infection are well documented, little is known about their molecular basis. We grew soybean (Glycine max) in a split-root growth system, inoculated half of each root system with R. reniformis, and quantified gene expression in infected and control root tissue at four dates after inoculation...

The number and location of mapped quantitative trait loci (QTL) depend on genetic populations and testing environments. The identification of consistent QTL across genetic backgrounds and environments is a pre-requisite to marker-assisted selection. This study analyzed a total of 661 abiotic and biotic stress resistance QTL based on our previous work and other publications using the meta-analysis software Biomercator. It identified chromosomal regions containing QTL clusters for different resistance traits and hotspots for a particular resistance trait in cotton from 98 QTL for drought tolerance under greenhouse (DT) and 150 QTL in field conditions (FDT), 80 QTL for salt tolerance in the greenhouse conditions (ST), 201 QTL for resistance to Verticillium wilt (VW, Verticillium dahliae), 47 QTL for resistance to Fusarium wilt (FW, Fusarium oxysporum f...

In the southeastern United States, reniform nematode (Rotylenchulus reniformis) is a serious pest of upland cotton (Gossypium hirsutum), a species which has no naturally occurring resistance against this nematode. To identify sources of reniform nematode resistance in species closely related to upland cotton, 222 G. arboreum accessions from the U.S. germplasm collection were evaluated in repeated growth chamber experiments. In initial screenings, root infection was measured 4 wks after inoculation. The 15 accessions supporting the fewest infections (PI 529992, PI 615755, PI 615766, PI 615788, PI 615848, PI 615856, PI 615950, PI 615977, PI 615991, PI 616008, PI 616016, PI 616062, PI 616126, PI 616159, and A2 553) were evaluated again in confirmation tests lasting 8 wk...

Five viruses were previously discovered infecting soybean cyst nematodes (SCN; Heterodera glycines) from greenhouse cultures maintained in Illinois. In this study, the five viruses [ScNV, ScPV, ScRV, ScTV, and SbCNV-5] were detected within SCN greenhouse and field populations from North Carolina (NC) and Missouri (MO). The prevalence and titers of viruses in SCN from 43 greenhouse cultures and 25 field populations were analyzed using qRT-PCR. Viral titers within SCN greenhouse cultures were similar throughout juvenile development, and the presence of viral anti-genomic RNAs within egg, second-stage juvenile (J2), and pooled J3 and J4 stages suggests active viral replication within the nematode...

Integration of genetic analysis, molecular biology, and genomic approaches drastically enhanced our understanding of genetic control of nematode resistance and provided effective breeding strategies in soybeans. Three nematode species, including soybean cyst (SCN, Heterodera glycine), root-knot (RKN, Meloidogyne incognita), and reniform (RN, Rotylenchulus reniformis), are the most destructive pests and have spread to soybean growing areas worldwide. Host plant resistance has played an important role in their control...

Comparative pathogenicity of reniform nematode on root-knot resistant ABT 10 and susceptible bidi tobacco A119 revealed that ABT 10 was found significantly superior to A119 with respect to plant growth characters and as good as A119 with respect to multiplication of reniform nematode. Initial inoculum of 1,000 J4 of the nematode found damaging to both ABT 10 and A119 varieties of bidi tobacco.

Estimation of avoidable loss in yield of bidi tobacco due to reniform nematode under pot conditions revealed that variety A 119 suffered heavily than ABT 10 due to reniform nematode. Inoculation of reniform nematode @ 2000 J4 per plant significantly reduced the plant growth characters and increased nematode multiplication preferring A 119 variety. Estimation of avoidable loss in cured shoot yield of bidi tobacco due to infection of reniform nematode in individual variety ABT 10 and A 119 has been estimated to the tune of 30...

U.S. cotton production is suffering from the yield loss caused by the reniform nematode (RN), Rotylenchulus reniformis. Management of this devastating pest is of utmost importance because, no upland cotton cultivar exhibits adequate resistance to RN. Nine populations of RN from distinct regions in Alabama and one population from Mississippi were studied and thirteen morphometric features were measured on 20 male and 20 female nematodes from each population. Highly correlated variables (positive) in female and male RN morphometric parameters were observed for body length (L) and distance of vulva from the lip region (V) (r = 0...

The reniform nematode (Rotylenchulus reniformis) causes significant cotton (Gossypium hirsutum) losses in the southeastern United States. The research objective was to describe the effects of two resistant G. barbadense lines (cultivar TX 110 and accession GB 713) on development and fecundity of reniform nematode. Nematode development and fecundity were evaluated on the resistant lines and susceptible G. hirsutum cultivar Deltapine 16 in three repeated growth chamber experiments. Nematode development on roots early and late in the infection cycle was measured at set intervals from 1 to 25 d after inoculation (DAI) and genotypes were compared based on the number of nematodes in four developmental stages (vermiform, swelling, reniform, and gravid)...

A taxonomic survey of six nematode species (including three new taxa) from the genus Cucullanus Müller, 1777, parasites of marine fishes off the Brazilian coast, is provided. Nematodes were studied using light and scanning electron microscopy (SEM). Cucullanus gastrophysi n. sp. parasitic in Lophius gastrophysus Miranda Ribeiro differs from its congeners by the combination of the following features: shape and number of sclerotized structures in the oesophastome (a pair of lateral elongate structures and a single small reniform one), position of deirids and excretory pore (both anterior to oesophagus base), spicule length and spicule/body length ratio (0...