scholarly journals Quantitative Trait Loci Controlling Amounts and Types of Epicuticular Waxes in Onion

2014 ◽  
Vol 139 (5) ◽  
pp. 597-602 ◽  
Author(s):  
Steven J. Damon ◽  
Michael J. Havey
Keyword(s):  
Insect Pest ◽  
Epicuticular Wax ◽  
Thrips Tabaci ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromosome 2 ◽  
Nucleotide Polymorphisms ◽  
Epicuticular Waxes ◽  
Onion Thrips ◽  
Chromosome 5 ◽  
Epicuticular Wax Biosynthesis

Natural variation exists in onion (Allium cepa L.) for amounts and types of epicuticular waxes on leaves. Wild-type waxy onion possesses copious amounts of these waxes, whereas the foliage of semiglossy and glossy phenotypes accumulates significantly less wax. Reduced amounts of epicuticular waxes have been associated with resistance to onion thrips (Thrips tabaci Lindeman), an important insect pest of onion. A segregating family from the cross of waxy and semiglossy onions was used to map single nucleotide polymorphisms (SNPs) and identify chromosome regions affecting amounts and types of epicuticular waxes as measured by gas chromatography–mass spectrometry. The amount of the primary epicuticular wax on onion leaves, hentriacontanone-16, was controlled by one region on chromosome 5. One region on chromosome 2 affected concentrations of several primary fatty alcohols. Results indicate that the region on chromosome 2 may be associated with the acyl reduction pathway, and the region on chromosome 5 may affect the decarbonylation pathway of epicuticular wax biosynthesis. Because lower amounts of epicuticular waxes are recessively inherited, SNPs tagging regions on chromosomes 2 and 5 will be useful for marker-assisted breeding to vary amounts and types of epicuticular waxes on onion foliage with the goal to develop cultivars resistant to onion thrips.

scholarly journals Genetic Analysis of the Unique Epicuticular Wax Profile of ‘Odourless Greenleaf’ Onion

2021 ◽  
pp. 1-7
Author(s):  
Michael J. Havey ◽  
Derek J. Hunsaker ◽  
Eduardo D. Munaiz
Keyword(s):  
Insect Pest ◽  
Epicuticular Wax ◽  
Thrips Tabaci ◽  
Genetic Maps ◽  
Gas Chromatography Mass Spectrometry ◽  
Nucleotide Polymorphisms ◽  
Epicuticular Waxes ◽  
Feeding Damage ◽  
Onion Thrips ◽  
Hybrid Plants

The amounts and types of epicuticular waxes on onion (Allium cepa) leaves affect the severity of feeding damage by onion thrips (Thrips tabaci), a serious insect pest of onion. Onion plants with light green leaves are referred to as “glossy” and accumulate less epicuticular wax relative to the blue–green (“waxy”) foliage of wild-type onion. The onion cultivar Odourless Greenleaf (OGL) has visually glossy foliage, shows resistance to thrips feeding damage, and has the unique profile of accumulating waxes with 28 or fewer carbons. Plants of glossy OGL were crossed with the glossy inbred B9885 and waxy inbred lines DH2107, DH066619, and B8667. Hybrid progenies from glossy OGL by waxy plants had waxy foliage, indicating recessiveness of the glossy OGL phenotype relative to the waxy phenotype. Hybrids from the cross of glossy OGL with glossy B9885 were also waxy, revealing different genetic bases for the glossy phenotype in these two onions. Hybrid plants were self-pollinated and segregations in F2 families from OGL × waxy crosses fit the expected 3:1 ratio for the single locus at which the homozygous recessive genotype conditions glossy foliage. Segregations in F2 families from crosses of glossy 9885 × glossy OGL fit the 9:7 ratio, supporting two independently segregating loci, where the recessive genotype at either locus conditions the glossy phenotype. Amounts and types of epicuticular waxes on leaves of F2 progenies from crosses of OGL × waxy B8667 and glossy B9885 × OGL were determined using gas chromatography-mass spectrometry. Single-nucleotide polymorphisms were genotyped and genetic maps were constructed. The visually glossy phenotype from OGL and its unique profile of epicuticular waxes were conditioned by one locus on chromosome 6, for which we propose the name glogl. Onion populations such as OGL with unique epicuticular wax profiles will be important germplasms for the development of onion cultivars that suffer less feeding damage from onion thrips compared with waxy onion.

scholarly journals Variation for Epicuticular Waxes on Onion Foliage and Impacts on Numbers of Onion Thrips

2014 ◽  
Vol 139 (4) ◽  
pp. 495-501 ◽  
Author(s):  
Steven J. Damon ◽  
Russell L. Groves ◽  
Michael J. Havey
Keyword(s):  
Natural Variation ◽  
Thrips Tabaci ◽  
Gas Chromatography Mass Spectrometry ◽  
Epicuticular Waxes ◽  
Feeding Damage ◽  
Wild Type ◽  
Onion Thrips ◽  
Integrated Programs ◽  
Foliar Pathogens ◽  
Wax Crystals

Natural variation exists in onion (Allium cepa L.) for amounts of epicuticular waxes on foliage, and plants with lower amounts of these waxes suffer less feeding damage from onion thrips (Thrips tabaci Lind.). Wild-type onion possesses copious amounts of epicuticular waxes and is often referred to as “waxy.” The recessively inherited “glossy” phenotype has significantly less wax relative to waxy types and shows resistance to onion thrips but is vulnerable to spray damage, foliar pathogens, and excessive transpiration. Phenotypes visually intermediate between waxy and glossy also exist in onion, which we refer to as “semiglossy.” Epicuticular waxes on the leaves of glossy, semiglossy, and waxy onions were evaluated for appearance using scanning electron microscopy (SEM) and amounts and types were analyzed using gas chromatography/mass spectrometry. Wax crystals were clearly visible on the surface of waxy foliage with decreasing amounts on semiglossy and none on glossy leaves. The ketone hentriacontanone-16 was the most prevalent wax on leaves of waxy onion and was significantly (P < 0.01) less on semiglossy relative to waxy plants and on glossy relative to waxy and semiglossy plants. Numbers of adult and immature onion thrips were significantly reduced (P < 0.05) on glossy and/or semiglossy accessions relative to waxy in field and greenhouse cage experiments. These results indicate that semiglossy plants possess intermediate amounts of epicuticular waxes that may protect leaves from diseases or environmental stresses while still conferring resistance to onion thrips. Therefore, the semiglossy phenotype should be useful in integrated programs managing this important onion pest.

scholarly journals Amounts and Types of Epicuticular Leaf Waxes among Onion Accessions Selected for Reduced Damage by Onion Thrips

2020 ◽  
Vol 145 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Eduardo D. Munaiz ◽  
Russell L. Groves ◽  
Michael J. Havey
Keyword(s):  
Gas Chromatography ◽  
Mass Spectroscopy ◽  
Insect Pest ◽  
Field Evaluation ◽  
Thrips Tabaci ◽  
Epicuticular Waxes ◽  
Feeding Damage ◽  
Yield Losses ◽  
Onion Thrips ◽  
Gas Chromatography Mass Spectroscopy

Onion thrips (Thrips tabaci) is the main insect pest of onion (Allium cepa), and feeding damage routinely causes serious yield losses. Lower amounts of epicuticular waxes on onion leaves have been associated with fewer onion thrips and less feeding damage, and research is needed to assess the relationships between amounts and composition of epicuticular waxes and feeding damage by onion thrips. This study used gas chromatography mass spectroscopy to determine amounts and types of epicuticular waxes on the foliage of onion accessions that had been field-selected for lower damage from onion thrips. Hentriacontanone-16 (H16), octaconasol-1, and triacontanol-1 were the most prevalent waxes on the foliage of these selections. Amounts of H16 were significantly lower on selections visually classified as having glossy or semiglossy foliage. Semiglossy selections were identified with similar amounts of total epicuticular wax as waxy phenotypes, due primarily to lower amounts of H16 and higher amounts of other waxes. These semiglossy selections suffered significantly less feeding damage from onion thrips in a field evaluation, supporting the identification of unique wax profiles toward the development of thrips-resistant onion.

scholarly journals Genetic Analyses of Epicuticular Waxes Associated with the Glossy Foliage of ‘White Persian’ Onion

2020 ◽  
Vol 145 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Eduardo D. Munaiz ◽  
Michael J. Havey
Keyword(s):  
Phenotypic Variation ◽  
Thrips Tabaci ◽  
Chromosome 8 ◽  
Chromosome 1 ◽  
Gas Chromatography Mass Spectrometry ◽  
Epicuticular Waxes ◽  
Onion Thrips ◽  
Genetic Analyses ◽  
Recessive Locus ◽  
The Cross

Onion (Allium cepa) plants with lower amounts of epicuticular waxes on foliage suffer less damage from the insect pest Thrips tabaci (onion thrips). Glossy onion accumulates significantly less epicuticular wax compared with wild-type “waxy” onion, and a single recessive locus (gl) has been proposed to condition this phenotype. Genetic analyses of types and amounts of epicuticular waxes were completed using two segregating families from the cross of the glossy inbreds B9885 and B9897 (both originally selected from the onion cultivar White Persian) with waxy inbred B8667 and semiglossy (intermediate amounts of waxes) inbred B5351, respectively. F2 progenies were grown in greenhouses and scored visually for foliar phenotypes, and amounts and types of epicuticular waxes were determined using gas chromatography-mass spectrometry (GCMS). For one F2 family from the cross of glossy B9885 by waxy B8667, visually scored glossy vs. waxy foliage fit a 1:3 ratio and the phenotype mapped to chromosome 8 of onion. This same region on chromosome 8 was significantly associated with amounts of the ketone hentriacontanone-16 (H16) and fatty alcohols 1-octacosanol (Oct1) and 1-triacontanol (Tri1). Visually scored F2 progeny from the cross of glossy B9897 × semiglossy B5351 did not fit expected models for one or two recessive loci. Significant quantitative trait loci (QTL) were revealed on chromosomes 5 and 8 controlling amounts of H16. Epistasis was detected between regions on chromosomes 1 and 8, and a 100-fold increase of H16 was conditioned by homozygous genotypes for the B5351 region on chromosome 1 and the B9885 region on chromosome 8. The three QTL model explained 41% of the phenotypic variation for amounts of H16 at logarithm of odds of 16.6. Amounts of Oct1 and Tri1 in the B9897 × B5351 family were associated with a major QTL on chromosome 1, explaining 37% to 46% of the phenotypic variation, respectively. This research demonstrates that glossy foliage of ‘White Persian’ onion is conditioned by a recessive locus on chromosome 8 for which we propose the name glwp. These results are important for selection of onion with unique profiles of epicuticular waxes to reduce losses resulting from onion thrips.

scholarly journals Identities of and Phenotypic Variation for Epicuticular Waxes among Leaves and Plants from Inbred Onion Populations

HortScience ◽  
2020 ◽  
Vol 55 (12) ◽  
pp. 2008-2010
Author(s):  
Jiffinvir Khosa ◽  
Derek Hunsaker ◽  
Michael J. Havey
Keyword(s):  
Mass Spectrometry ◽  
Thrips Tabaci ◽  
Gas Chromatography Mass Spectrometry ◽  
Epicuticular Waxes ◽  
Response To Selection ◽  
Feeding Damage ◽  
Onion Thrips ◽  
Coefficients Of Variation ◽  
Selection For ◽  
Over Time

The amounts and types of epicuticular waxes on onion (Allium cepa) leaves affect feeding damage by onion thrips (Thrips tabaci). This study used gas chromatography mass spectrometry (GCMS) to establish the identities of waxes and measure over time wax amounts on leaves of inbred onion plants with glossy, semiglossy, and waxy foliage. Nine waxes were detected on leaves of all inbreds, and higher coefficients of variation (cv) were observed for less abundant waxes on foliage of doubled haploid onions. Older leaves had higher amounts of waxes compared with younger leaves on the same plant. Except for one minor wax, amounts of individual waxes on leaves were not significantly different for plants of different ages. There was a significant inbred by sampling date interaction due to lower amounts of waxes on the leaves of older plants from the semiglossy inbred. These results indicate that there is little advantage to multiple samplings of leaves over time from the same plant and resources may be better used to evaluate more plants. The relatively large cvs for amounts of specific waxes may reduce response to selection for unique epicuticular wax profiles to develop onion populations that suffer less feeding damage by onion thrips.

scholarly journals Managing Onion Thrips can Limit Bacterial Stalk and Leaf Necrosis in Michigan Onion Fields

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 938-943 ◽  
Author(s):  
A. S. Grode ◽  
E. Brisco-McCann ◽  
P. Wiriyajitsonboom ◽  
M. K. Hausbeck ◽  
Z. Szendrei
Keyword(s):  
Cultural Practices ◽  
Disease Incidence ◽  
Insect Pest ◽  
Management Program ◽  
Thrips Tabaci ◽  
Onion Thrips ◽  
Leaf Necrosis ◽  
Positive Correlations ◽  
Thrips Population ◽  
Reduce Disease Severity

Onion thrips (Thrips tabaci) is a major insect pest of onion and it has been identified as a likely vector of Pantoea agglomerans (bacterial stalk and leaf necrosis), a relatively new pathogen to Michigan’s onion industry. Our objective was to develop an integrated insect and disease management program by examining the efficacy of bactericides and insecticides alone and in combination to limit bacterial stalk and leaf necrosis caused by P. agglomerans. We also examined the association of onion thrips and disease incidence in the field, because thrips are known to transmit this pathogen. In the pesticide trial, insecticides reduced both thrips abundance and bacterial stalk and leaf necrosis incidence whereas bactericides alone did not reduce disease severity. Positive correlations among thrips population density, numbers of thrips positive for P. agglomerans, and bacterial stalk and leaf necrosis incidence in onion fields were determined. This study suggests that onion thrips feeding can facilitate the development of bacterial stalk and leaf necrosis in Michigan’s commercial onion fields, and results from the pesticide trials indicate that thrips feeding damage is positively correlated with disease incidence. Therefore, in order to reduce bacterial stalk and leaf necrosis incidence in onion, management efforts should include reducing onion thrips populations through the use of insecticides and other cultural practices.

scholarly journals Monitoring onion crops for onion thrips Thrips tabaci

2006 ◽  
Vol 59 ◽  
pp. 69-74
Author(s):  
N.A. Martin ◽  
P.J. Workman ◽  
D. Hedderley
Keyword(s):  
New Zealand ◽  
Insect Pest ◽  
Thrips Tabaci ◽  
Sampling Strategies ◽  
Onion Thrips ◽  
Before And After

Onion thrips Thrips tabaci (Thysanoptera Thripidae) is the main insect pest on New Zealand onions The onion industry recommends monitoring 50 or 100 plants in 10 or 20 groups of 5 plants and applying a cluster of insecticides when populations reach 01 thrips/plant The robustness of these guidelines was tested by monitoring six crops before and after the first cluster of insecticides Two people each recorded the numbers of adult and larval thrips in each crop on each occasion using the following strategies (1) 100 randomly stratified plants (2) 20 groups of five plants randomly selected from 1 m2 and (3) 20 groups of five adjacent plants giving a total of 300 plants sampled When sampling 100 plants estimates of thrips/plant were similar for each of the three sampling strategies However to obtain a particular level of precision fewer plants could be sampled using stratified randomly selected plants than groups of five plants

scholarly journals Distribution et dégâts associés au thrips de l’oignon, Thrips tabaci L. (Thysanoptera : Thripidae) en fonction de la zone agro-climatique au Burkina Faso

2020 ◽  
Vol 14 (6) ◽  
pp. 2037-2048
Author(s):  
Abdoulaye Savadogo ◽  
Boniface Babo Bakouan ◽  
Mathieu Wendnéyidé Sawadogo ◽  
Karim Nébié ◽  
Rémy Dabiré ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Crop Production ◽  
Insect Pest ◽  
Average Density ◽  
Thrips Tabaci ◽  
Annual Rainfall ◽  
Onion Thrips ◽  
Average Annual Temperature ◽  
Average Annual Rainfall ◽  
Plateau Central

L’oignon est le premier légume produit au Burkina Faso. Thrips tabaci constitue son principal insecte ravageur. Ce travail avait pour objectif  d’évaluer la distribution, l’incidence et la sévérité des attaques de T. tabaci sur l’oignon. L’étude a été réalisée dans trois bassins de production  représentatifs de deux zones agroécologiques du Burkina Faso : la zone sahélienne caractérisée par une pluviosité moyenne annuelle inférieure à 600 mm et une température moyenne annuelle de 35 °C ; contre une pluviosité moyenne annuelle comprise entre 600 et 900 mm et une  température moyenne annuelle de 33 °C pour la zone nord soudanienne Nous avons réalisé des prospections dans 45 parcelles paysannes dans les zones de production ciblées. Des plantes d’oignon ont été prélevées dans trois quadrats posés sur une des diagonales de chaque parcelle, et les thrips trouvés sur chaque plante de chaque quadrat comptés. Tous les plants à l’intérieur du quadrat ont été donc observés. La densité moyenne la plus élevée (216 ±385 thrips au m2) a été observée dans la région du Nord tandis que l’incidence moyenne la plus élevée (95,91±8,92%) a été observée dans la Boucle du Mouhoun. La plus faible sévérité (19,29±13,27%) a été enregistrée dans le Plateau central. Cette étude est un premier pas vers le développement de stratégies alternatives de lutte contre les parasites dans le cadre de systèmes de production végétale durables à l’aide de bonnes pratiques agricoles et de l’utilisation des pesticides biologiques.Mots clés : Oignon, Thrips tabaci, incidence, sévérité, répartition, Burkina Faso.   English Title: Distribution and damage associated with the onion thrips, Thrips tabaci L. (Thysanoptera: Thripidae) according to the agro-climatic zone in Burkina FasoOnion is the first vegetable produced in Burkina Faso. Thrips tabaci is its main insect pest. We assessed the distribution, incidence and severity of T. tabaci attacks on onion in three-production areas representative of two agroecological zones of Burkina Faso: the the Sahelian zone characterized by an average annual rainfall of less than 600 mm and an average annual temperature of 35 °C; compared to an average annual rainfall of between 600 and 900 mm and an average annual temperature of 33 °C for the northern Sudanian zone. We carried out surveys in 45 farmer plots in the targeted production zones. Thus, onion plants were taken from three quadrats placed on one of the diagonals of each plot, and the thrips found on each plant were counted. All plants within the quadrat were therefore observed. The highest average density (216±385 thrips per m²) was observed in the North while the highest average incidence (95.91±8.92%) was observed in the Boucle du Mouhoun. The lowest severity (19.29±13.27%) was recorded in the Plateau central region. This study is a first step towards the development of alternative pest control strategies within sustainable crop production systems using good agricultural practices and the use of biopesticides.Keywords: Onion, Thrips tabaci, incidence, severity, distribution, Burkina Faso.

scholarly journals Reflectance Spectroscopy for Non-Destructive Measurement and Genetic Analysis of Amounts and Types of Epicuticular Waxes on Onion Leaves

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3454 ◽  
Author(s):  
Eduardo D. Munaiz ◽  
Philip A. Townsend ◽  
Michael J. Havey
Keyword(s):  
Prediction Models ◽  
Full Range ◽  
Reflectance Spectroscopy ◽  
Thrips Tabaci ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectral Features ◽  
Epicuticular Waxes ◽  
Least Squares Regression ◽  
Destructive Measurement ◽  
Non Destructive

Epicuticular waxes on the surface of plant leaves are important for the tolerance to abiotic stresses and plant–parasite interactions. In the onion (Allium cepa L.), the variation for the amounts and types of epicuticular waxes is significantly associated with less feeding damage by the insect Thrips tabaci (thrips). Epicuticular wax profiles are measured using used gas chromatography mass spectrometry (GCMS), which is a labor intensive and relatively expensive approach. Biochemical spectroscopy is a non-destructive tool for measurement and analysis of physiological and chemical features of plants. This study used GCMS and full-range biochemical spectroscopy to characterize epicuticular waxes on seven onion accessions with visually glossy (low wax), semi-glossy (intermediate wax), or waxy (copious wax) foliage, as well as a segregating family from the cross of glossy and waxy onions. In agreement with previous studies, GCMS revealed that the three main waxes on the leaves of a wild type waxy onion were the ketone hentriacontanone-16 (H16) and fatty alcohols octacosanol-1 (Oct) and triacontanol-1 (Tri). The glossy cultivar “Odourless Greenleaf” had a unique phenotype with essentially no H16 and Tri and higher amounts of Oct and the fatty alcohol hexacosanol-1 (Hex). Hyperspectral reflectance profiles were measured on leaves of the onion accessions and segregating family, and partial least-squares regression (PLSR) was utilized to generate a spectral coefficient for every wavelength and prediction models for the amounts of the three major wax components. PLSR predictions were robust with independent validation coefficients of determination at 0.72, 0.70, and 0.42 for H16, Oct, and Tri, respectively. The predicted amounts of H16, Oct, and Tri are the result of an additive effect of multiple spectral features of different intensities. The variation of reflectance for H16, Oct, and Tri revealed unique spectral features at 2259 nm, 645 nm, and 730 nm, respectively. Reflectance spectroscopy successfully revealed a major quantitative trait locus (QTL) for amounts of H16, Oct, and Tri in the segregating family, agreeing with previous genetic studies. This study demonstrates that hyperspectral signatures can be used for non-destructive measurement of major waxes on onion leaves as a basis for rapid plant assessment in support of developing thrips-resistant onions.

scholarly journals Epicuticular Wax and White Pine Blister Rust Resistance in Resistant and Susceptible Selections of Eastern White Pine (Pinus strobus)

2006 ◽  
Vol 96 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Jason A. Smith ◽  
Robert A. Blanchette ◽  
Todd A. Burnes ◽  
Jeffrey H. Gillman ◽  
Andrew J. David
Keyword(s):  
Resistance Mechanism ◽  
Environmental Scanning Electron Microscopy ◽  
Pinus Strobus ◽  
Epicuticular Wax ◽  
Gas Chromatography Mass Spectrometry ◽  
Environmental Scanning ◽  
Epicuticular Waxes ◽  
White Pine Blister Rust ◽  
White Pine ◽  
Eastern White Pine

Epicuticular wax on needles was evaluated for its influence on Cronartium ribicola infection of resistant and susceptible selections of Pinus strobus. Environmental scanning electron microscopy comparisons revealed that needles from a resistant selection of eastern white pine, P327, had a significantly higher percentage of stomata that were occluded with wax, fewer basidiospores germinating at 48 h after inoculation, and fewer germ tubes penetrating stomata than needles from a susceptible selection H111. In addition, needles from seedlings that failed to develop symptoms 6 weeks after inoculation, from a cross between P327 and susceptible parent H109, had a significantly higher percentage of stomata occluded with wax compared with needles from seedlings that developed symptoms. In experiments where epicuticular waxes were removed from needles before seedlings were infected, resistant seedlings without wax developed approximately the same number of infection spots (as measured by spot index) as susceptible seedlings with wax intact. Gas chromatography/mass spectrometry comparisons of extracted epicuticular waxes revealed several peaks that were specific to P327 and not found in susceptible H111 suggesting biochemical differences in wax composition. These results implicate the role of epicuticular waxes as a resistance mechanism in P. strobus selection P327 and suggest a role for waxes in reducing spore germination and subsequent infection through stomatal openings.

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