Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| brain cholinesterase inhibition in songbirds from pecan groves sprayed with phosalone and disulfoton. | brain cholinesterase (che) activities of songbirds collected in pecan groves 6 to 7 hr after separate applications of the organophosphorus pesticides, phosalone and disulfoton, were compared to mean che activities of controls (normals) as a measure of insecticide exposure. in general, reduction of brain che activity greater than or equal to 2 standard deviations below the control mean indicates exposure to an anticholinesterase compound. phosalone had little effect on brain che activity of birds ... | 1990 | 2304190 |
| poisoning of canada geese in texas by parathion sprayed for control of russian wheat aphid. | approximately 200 canada geese (branta canadensis) died at a playa lake in the texas panhandle shortly after a winter wheat field in the basin adjacent to the lake was treated with parathion to control newly invading russian wheat aphids (diuraphis noxia). no evidence of infectious disease was diagnosed during necropsies of geese. brain che activities were depressed up to 77% below normal. parathion residues in gi tract contents of geese ranged from 4 to 34 ppm. based on this evidence, parathion ... | 1991 | 2067047 |
| genetic variation and phylogenetic relationships among worldwide collections of the russian wheat aphid, diuraphis noxia (mordvilko), inferred from allozyme and rapd-pcr markers. | genetic analyses were conducted on diuraphis noxia (mordvilko) populations collected from wheat, barley and other grasses from various countries throughout the world. these collections had been found to contain clones that differed in virulence from various cultivars, cuticular hydrocarbon profiles and life cycle characters. discrete genetic markers analysed in this study included allozymes and arbitrary regions of the genome amplified by the polymerase chain reaction (rapd-pcr). in all, 23 enzy ... | 1993 | 8335479 |
| in vitro selection for russian wheat aphid (diuraphis noxia) resistance in wheat (triticum aestivum). | the russian wheat aphid (diuraphis noxia) is a pest on wheat (triticum aestivum) in many regions of the world. the aphid injects a phytotoxin when it feeds. identification of somaclonal variants with phytotoxin resistance may shorten development time for resistance. wheat calli from the susceptible cultivar 'stephens' were exposed to an extract from the aphid. five plants were regenerated from 100 treated calli. resistance to the aphid was observed in both the r2 and r3 generations. one of the s ... | 1993 | 24197254 |
| an early indicator of resistance in barley to russian wheat aphid. | during early stages of infestation by russian wheat aphids (diuraphis noxia [mordvilko]; rwas), barley (hordeum vulgare l.) leaf cells collapsed and showed autofluorescence in the mesophyll and bundle sheath adjacent to the rwa stylet sheath. the response was visually similar to the hypersensitive cell death response, typical of resistance to microbial pathogens. resistant barley produced significantly more collapsed, autofluorescent cells (cac) than did susceptible barley. rwa stylet entry site ... | 1994 | 12232285 |
| olfactory responses of the parasitoiddiaeretiella rapae (hymenoptera: aphidiidae) to odor of plants, aphids, and plant-aphid complexes. | diaeretiella rapae (m'intosh) (hymenoptera: aphidiidae) is a parasitoid of several aphid species, including the russian wheat aphid (rwa),diuraphis noxia (mordvilko), and the cabbage aphid (ca).brevicoryne brassicae (l.). the response of matedd. rapae females to odors from wheat, cabbage, and plant-host complexes was investigated using a four-choice olfactometer. experienced parasitoids, but not inexperienced females, responded positively to odors of the wheat-rwa complex in a no-choice test. in ... | 1995 | 24234172 |
| the endosymbiont (buchnera sp.) of the aphid diuraphis noxia contains plasmids consisting of trpeg and tandem repeats of trpeg pseudogenes. | most aphids are dependent for their survival on prokaryotic endosymbionts assigned to the genus buchnera. among the functions of buchnera species is the synthesis of tryptophan, which is required by the aphid host. in buchnera species from the aphid diuraphis noxia, the genes for anthranilate synthase (trpeg) were found on a plasmid which consisted of seven tandem repeats of a 3.2-kb unit and one 2.6-kb unit which differed in containing a 0.6-kb deletion. one of the 3.2-kb units contained open r ... | 1996 | 8593038 |
| endosymbionts (buchnera) from the aphids schizaphis graminum and diuraphis noxia have different copy numbers of the plasmid containing the leucine biosynthetic genes. | the prokaryotic endosymbiont (buchnera) of the aphid schizaphis graminum contains 24 copies of a plasmid that has genes encoding enzymes of the leucine biosynthetic pathway while the endosymbiont of the related aphid diuraphis noxia has only one copy of this plasmid. these results, in conjunction with similar results for the trpeg-containing plasmids, suggest that d. noxia has a reduced demand for endosymbiont-derived essential amino acids. | 1998 | 9504992 |
| the endosymbiont (buchnera) of the aphid diuraphis noxia contains all the genes of the tryptophan biosynthetic pathway. | previously it has been shown that the prokaryotic endosymbiont (buchnera) of the aphid diuraphis noxia contains a plasmid consisting of one copy of the gene for anthranilate synthase (trpeg) and seven trpeg pseudogenes. in the present communication we show that this endosymbiont contains the remaining genes of the tryptophan biosynthetic pathway [trpdc(f)ba] which appear to be functional in that they code for the complete enzyme proteins and are not pseudogenes. as in the case of buchnera from o ... | 1998 | 9625791 |
| relative efficacy of blastospores and aerial conidia of paecilomyces fumosoroseus against the russian wheat aphid. | 1998 | 9709022 | |
| use of the green fluorescent protein for investigations of paecilomyces fumosoroseus in insect hosts. | the green fluorescent protein (gfp) from the jellyfish aequorea victoria has been expressed in a variety of prokaryotic and eukaryotic organisms and has been used extensively as a marker in the study of host-pathogen interactions. we have expressed gfp in the entomopathogenic fungus paecilomyces fumosoroseus through co-transformation with a vector that confers resistance to glufosinate ammonium. all cell types express gfp and were readily detected by fluorescence microscopy. no correlation was o ... | 1999 | 10486232 |
| genetic characterization of plasmids containing genes encoding enzymes of leucine biosynthesis in endosymbionts (buchnera) of aphids. | the prokaryotic endosymbionts (buchnera) of aphids are known to provision their hosts with amino acids that are limiting in the aphid diet. buchnera from the aphids schizaphis graminum and diuraphis noxia have plasmids containing leuabcd, genes that encode enzymes of the leucine biosynthetic pathway, as well as genes encoding proteins probably involved in plasmid replication (repa1 and repa2) and an open reading frame (orf1) of unknown function. the newly reported plasmids closely resemble a pla ... | 1999 | 9873079 |
| genetic transformation and mutagenesis of the entomopathogenic fungus paecilomyces fumosoroseus | we have developed a dna-mediated transformation system for the entomopathogenic fungus paecilomyces fumosoroseus based on resistance to the herbicide glufosinate ammonium. the resistance is provided by the bar gene from streptomyces hygroscopicus and is under the control of the aspergillus nidulans trpc promoter and terminator sequences. frequencies of up to 110 transformants/&mgr;g of linearized plasmid dna were obtained aided by the addition of the nuclease inhibitor, aurintricarboxylic acid ( ... | 1999 | 10534416 |
| molecular characterization of the leucine plasmid from buchnera aphidicola, primary endosymbiont of the aphid acyrthosiphon pisum. | the complete sequence of the leucine plasmid of buchnera aphidicola from the aphid acyrthosiphon pisum (pleu-bap) is reported. its gene organization was concordant with those of other leucine plasmids of buchnera from aphids of the aphidini and macrosiphini tribes. three inverted repeats are present in pleu-bap. two of them are also present in pleu from the family aphididae: (i) sir1, located downstream the leucine operon, resembles a rho-independent terminator of transcription, and (ii) lir1, l ... | 2000 | 10688696 |
| seasonal dynamics of cereal aphids on russian wheat aphid (homoptera: aphididae) susceptible and resistant wheats. | field experiments were conducted in 1997 and 1998 to evaluate the impact of resistance to russian wheat aphid, diuraphis noxia (mordvilko), on the cereal aphid complex in wheat. two spring wheats were planted: the variety "centennial" (russian wheat aphid susceptible) and the advanced line ido488 (russian wheat aphid resistant). ido488 incorporates the resistance found in pi 294994 into a centennial background. field plots were artificially infested with adult d. noxia and sampled weekly. the mo ... | 2000 | 10902358 |
| decay of mutualistic potential in aphid endosymbionts through silencing of biosynthetic loci: buchnera of diuraphis. | buchnera, the primary bacterial endosymbiont of aphids, is known to provision essential amino acids lacking in the hosts' diet of plant sap. the recent discovery of silenced copies of genes for tryptophan biosynthesis (trpeg) in certain buchnera lineages suggests a decay in symbiotic functions in some aphid species. however, neither the distribution of pseudogenes among lineages nor the impact of this gene silencing on amino-acid availability in hosts has been assessed. in buchnera of the aphid ... | 2000 | 10983826 |
| nutritional enhancement of host plants by aphids - a comparison of three aphid species on grasses. | three aphid species were compared with respect to ability of enhancing the nutritional quality of their host plants. rhopalosiphum padi, which does not induce macroscopic changes in its host plants, was compared with schizaphis graminum and diuraphis noxia, both of which induce distinctive types of chlorotic lesions. phloem sap samples were collected from severed stylets of feeding aphids and from exudates of cut leaves of plants uninfested or infested with each aphid species. samples were analy ... | 2000 | 12770256 |
| relative suitability of crested wheatgrass and other perennial grass hosts for the russian wheat aphid (homoptera: aphididae). | the russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae), reproduces parthenogenetically in north america and must survive year-round on host plants, including in late summer when small grains are not in cultivation. during this time, cool-season perennial wheatgrasses (poaceae: triticeae) contribute substantially to aphid survival, crested wheatgrass (agropyron spp.) particularly. in greenhouse studies, the number of aphids per plant was measured after four infestation period ... | 2000 | 10826180 |
| induced life cycle transition from holocycly to anholocycly of the russian wheat aphid (homoptera: aphididae). | the russian wheat aphid (rwa),diuraphis noxia (mordvilko), exists with holocyclic life cycle in tacheng, xinjiang in northwest china. it produces males and oviparae to mate and oviposit for overwintering by eggs. under laboratory conditions with 14 h/d photophase and temperature not lower than 15 degrees c, rwa occurred in parthenogenesis and produced no males. the laboratory populations of russian wheat aphid, which were kept under natural conditions in fall by 15th, 49th and 81st generation wh ... | 2001 | 18763082 |
| oxidative responses of resistant and susceptible cereal leaves to symptomatic and nonsymptomatic cereal aphid (hemiptera: aphididae) feeding. | the impact of the leaf-chlorosis-eliciting russian wheat aphid, diuraphis noxia (mordvilko), and the nonchlorosis-eliciting bird cherry-oat aphid, rhopalosiphum padi (l.), feeding on d. noxia-susceptible and -resistant cereals was examined during the period (i.e., 3, 6, and 9 d after aphid infestation) that leaf chlorosis developed. after aphid number, leaf rolling and chlorosis ratings, and fresh leaf weight were recorded on each sampling date, total protein content, peroxidase, catalase, and p ... | 2001 | 11425032 |
| physiological modification of the host feeding site by cereal aphids (homoptera: aphididae). | indole-3-acetic acid-l-14c and 14c-sucrose labels were used to study the effects of greenbugs, schizaphis graminum (rondani), and russian wheat aphids, diuraphis noxia (mordvilko), on phloem function of wheat (triticum aesticum l.). greenbug feeding significantly reduced translocation from the immediate feeding site; however, phloem integrity was not impeded. in contrast, russian wheat aphids had little effect on vein loading or phloem translocation at the feeding site. similar results were obta ... | 2002 | 12020028 |
| registration of three wheat germplasms resistant to diuraphis noxia. | 2002 | 11756312 | |
| identification of microsatellite markers linked to russian wheat aphid resistance genes dn4 and dn6. | the russian wheat aphid (rwa), diuraphis noxia (mordvilko), is a serious economic pest of wheat worldwide. host plant resistance is the preferred method to control rwa infestations. the identification and mapping of rwa-resistant genes and the development of resistant wheat cultivars can be facilitated through the use of molecular markers. in the present study, microsatellite (ssr) markers linked to the rwa-resistant genes dn4 and dn6 were identified using several f(2) mapping populations derive ... | 2002 | 12582610 |
| characterisation of triticum vavilovii-derived stripe rust resistance using genetic, cytogenetic and molecular analyses and its marker-assisted selection. | stripe rust resistance was identified in triticum vavilovii( t. vaviloviiaus22498)-derived russian wheat aphid (rwa)-resistant germplasm. inheritance studies indicated monogenic control of resistance. the resistance gene was tentatively designated as yrvav and was located on chromosome 1b by monosomic analysis. a close association (1.5+/-0.9% recombination) of yrvav with a t. vavilovii-derived gliadin allele ( gli-b1vav) placed it in chromosome arm 1bs. yrvavwas allelic with yr10. tests with yr1 ... | 2002 | 12582703 |
| evaluation of tolerance of 20 wheat cultivars to russian wheat aphid diuraphis noxza (mordvilko) at seedling stage under greenhouse conditions. | the russian wheat aphid (r.w.a) is an aggressive pest of wheat, barley and other small grains in different parts of the world and during, the recent years in iran. this aphid causes high damage, so that much insecticides have been used against it. at present time utilization of resistant varieties is one of the most important methods to control it. therefore in order to evaluate the tolerance of 20 wheat cultivars, seeds were planted in 18 cm diameter plastic pots and put in cages. one week afte ... | 2003 | 15149118 |
| genetic mapping of dn7, a rye gene conferring resistance to the russian wheat aphid in wheat. | the russian wheat aphid is a significant pest problem in wheat and barley in north america. genetic resistance in wheat is the most effective and economical means to control the damage caused by the aphid. dn7 is a rye gene located on chromosome 1rs that confers resistance to the russian wheat aphid. the gene was previously transferred from rye into a wheat background via a 1rs/1bl translocation. this study was conducted to genetically map dn7 and to characterize the type of resistance the gene ... | 2003 | 12879254 |
| homoeologous set of nbs-lrr genes located at leaf and stripe rust resistance loci on short arms of chromosome 1 of wheat. | homoeologous group 1 chromosomes of wheat contain important genes that confer resistance to leaf, stem and stripe rusts, powdery mildew and russian wheat aphid. a disease resistance gene analog encoding nucleotide binding site-leucine rich repeat (nbs-lrr), designated rgayr10, was previously identified at the stripe rust resistant locus, yr10, located on chromosome 1bs distal to the storage protein, gli-b1locus. rgayr10 identified gene members in the homoeologous region of chromosome 1ds cosegre ... | 2003 | 12590346 |
| comparison of chlorophyll and carotenoid concentrations among russian wheat aphid (homoptera: aphididae)-infested wheat isolines. | russian wheat aphid, diuraphis noxia (mordvilko), feeding injury on 'betta' wheat isolines with the dn1 and dn2 genes was compared by assessing chlorophyll and carotenoid concentrations, and aphid fecundity. the resistant betta isolines (i.e., betta-dn1 and betta-dn2) supported similar numbers of aphids, but had significantly fewer than the susceptible betta wheat, indicating these lines are resistant to aphid feeding. diuraphis noxia feeding resulted in different responses in total chlorophyll ... | 2003 | 14994818 |
| plant damage and yield response to the russian wheat aphid (homoptera: aphididae) on susceptible and resistant winter wheats in colorado. | plant damage and yield response to the russian wheat aphid, diuraphis noxia (mordvilko), were evaluated on a susceptible (tam 107) and a resistant (rwa e1) winter wheat, triticum aestivum l., in three colorado locations in the 1993 and 1994 crop years. russian wheat aphid was more abundant on tam 107 than on rwa e1. russian wheat aphid days per tiller were greater at the higher infestation levels. yield losses as a result of russian wheat aphid infestation occurred most of the time with tam 107 ... | 2003 | 14994801 |
| genetic variation and founder effects in the parasitoid wasp, diaeretiella rapae (m'intosh) (hymenoptera: braconidae: aphidiidae), affecting its potential as a biological control agent. | the effects of recent colonization on the aphid parasitoid, diaeretiella rapae (m'intosh) (hymenoptera: braconidae: aphidiidae), in western australia were investigated. when compared with populations from the old world, the results of a microsatellite analysis show that the insects have low allelic length and low allele frequency variation, revealing that these individuals experienced a significant founder effect. marked genetic differentiation between populations was also revealed, which has po ... | 2003 | 14629347 |
| categories of resistance at four growth stages in three wheats resistant to the russian wheat aphid (homoptera: aphididae). | laboratory experiments were conducted to determine categories of resistance to russian wheat aphid, diuraphis noxia (mordvilko), in three wheats, triticum aestivum l, (pi 372129, pi 243781, and pi 222668) at zadoks growth stages 10, 20, 30, and 40. 'tam 107' was used as the susceptible standard. antixenosis was observed in pi 222668 and pi 372129. antibiosis was expressed as reduced nymphipositional period, daily nymph production, and fecundity at the jointing (zadoks 30) and boot (zadoks 40) st ... | 2003 | 12852604 |
| categories of resistance at different growth stages in halt, a winter wheat resistant to the russian wheat aphid (homoptera: aphididae). | this study was designed to categorize the resistance to the russian wheat aphid, diuraphis noxia (mordvilko), resistant hard red winter wheat, halt, as compared with susceptible wheat, tam 107, at four different growth stages. antixenosis was expressed in halt at growth stage zadoks 30. antibiosis in halt affected fecundity, number of aphids produced per reproductive day, maximum number of nymphs produced in one day, and intrinsic rate of increase. fecundity was lower on halt than tam 107, and m ... | 2003 | 12650365 |
| light activation of russian wheat aphid-elicited physiological responses in susceptible wheat. | the impact of light and its role in russian wheat aphid, diuraphis noxia (mordvilko), damage symptom formation, and photosynthetic capacity in 'arapahoe' wheat (triticum aestivum l.) were examined. after 72 h under continuous dark or continuous light regimes, the number of aphids (nymphs), leaf rolling and chlorosis ratings, fresh leaf weight, and chlorophyll contents were recorded. photosynthetic rates, chlorophyll a, kinetics and chlorophyll extractions also were determined. aphid infestation ... | 2003 | 12650362 |
| biotypic and pest status differences between hungarian and south african populations of russian wheat aphid, diuraphis noxia (kurdjumov) (homoptera: aphididae). | russian wheat aphid, diuraphis noxia (kurdjumov) is a severe pest of cereals in south africa and in the usa. in order to reduce d noxia damage, intensive resistance breeding programs have been undertaken, resulting in d noxia-resistant cultivars that are now widely used in south africa and in the usa. however, there appear to be differences in the ability of different populations of d noxia to damage these resistant cereal cultivars. to determine whether different biotypes of d noxia are present ... | 2003 | 14561073 |
| effectiveness of predators and parasitoids for the natural control of diuraphis noxia (homoptera: aphididae) on barley in central ethiopia. | the russian wheat aphid, diuraphis noxia (kurdj.), is a serious threat for the production of barley, hordeum vulgare l., in ethiopia. the pest can cause up to 100% yield losses in years of heavy infestation. natural control of d. noxia by using predators and parasitoids might be the best alternative both from economical and ecological point of view. in this regard, a field investigation was conducted during the 2001 spring cropping season at fitche, central ethiopia to determine abundance of d. ... | 2003 | 15149108 |
| glutenin and gliadin contents of flour derived from wheat infested with different aphid species. | aphid feeding in cereals results in both quantitative and qualitative yield losses; moreover aphid-transmitted viruses are responsible for other quantitative and qualitative damage so that direct or indirect effects of aphid infection are always of interest. at the beginning of stem elongation, wheat plants were caged regardless of the presence or absence of indigenous cereal aphids. half of the caged plants were artificially infected with diuraphis noxia. the number of d noxia and rhopalosiphum ... | 2003 | 12701703 |
| molecular mapping of the stb4 gene for resistance to septoria tritici blotch in wheat. | abstract breeding wheat for resistance is the most effective means to control septoria tritici blotch (stb), caused by the ascomycete mycosphaerella graminicola (anamorph septoria tritici). at least eight genes that confer resistance to stb in wheat have been identified. among them, the stb4 locus from the wheat cv. tadinia showed resistance to m. graminicola at both seedling and adult-plant stages. however, no attempt has been made to map the stb4 locus in the wheat genome. a mapping population ... | 2004 | 18944455 |
| identification of russian wheat aphid (homoptera: aphididae) populations virulent to the dn4 resistance gene. | the russian wheat aphid, diuraphis noxia (mordvilko), is a serious worldwide pest of wheat and barley. russian wheat aphid populations from hungary, russia, and syria have previously been identified as virulent to d. noxia (dn) 4, the gene in all russian wheat aphid-resistant cultivars produced in colorado. however, the virulence of russian wheat aphid populations from central europe, north africa, and south america to existing dn genes has not been assessed. experiments with plants containing s ... | 2004 | 15279298 |
| proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted volatile organic compounds in arabidopsis. | plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic microbes. although some characterization of root exudates has been achieved, especially of secondary metabolites and proteins, much less is known about volatile organic compounds (vocs) released by roots. in this communication, we describe a novel approach to exploring these rhizosphere vocs and th ... | 2004 | 15141066 |
| effect of serial transfer of three strains of paecilomyces fumosoroseus on growth in vitro, virulence, and host specificity. | serial passage of entomopathogenic hyphomycetes has been shown to alter virulence and host specificity. we evaluated virulence, host specificity, biomass production, conidiation, conidial germination, and a genetic fingerprint of 3 strains of paecilomyces fumosoroseus after passage in vitro or in vivo in diuraphis noxia or plutella xylostella. strain 4461 did not change in virulence toward d. noxia or p. xylostella after 30 passages in vitro nor after 15 passages in d. noxia. however, it lost vi ... | 2004 | 14992859 |
| biological control of cereal aphids in north america and mediating effects of host plant and habitat manipulations. | the predator and parasitoid fauna associated with cereal aphids is described, emphasizing the fauna associated with classical biological control efforts against the greenbug and russian wheat aphid. we focus on literature from north america and include work from europe and elsewhere when it is desirable to draw contrasts between approaches that affect cereal aphid biological control. effects on natural enemies of cereal aphids are described that appear associated with plant traits that are innat ... | 2004 | 14651463 |
| field evaluation of emmer wheat-derived synthetic hexaploid wheat for resistance to russian wheat aphid (homoptera: aphididae). | broadening the genetic base for resistance to russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae), in bread wheat, triticum aestivum l., is desirable. to date, identified russian wheat aphid resistance genes are either located to the d chromosomes or to rye translocation of wheat, and resistance derived from the a or b genomes of tetraploid triticum spp. would therefore be highly beneficial. fifty-eight synthetic hexaploid wheat, derived from interspecific crosses of triticum ... | 2004 | 15279292 |
| enzymatic chlorophyll degradation in wheat near-isogenic lines elicited by cereal aphid (homoptera: aphididae) feeding. | chlorophyll degradation enzyme (i.e., chlorophyllase, mg-dechelatase, and chlorophyll oxidase) activities of aphid-infested and uninfested 'tugela' and tugela near-isogenic wheat lines (i.e., tugela-dn1, tugela-dn2, and tugela-dn5) were assayed. chlorophyllase activity was higher in bird cherry-oat aphid, rhopalosiphum padi (l.) (homoptera: aphididae),-infested wheat lines compared with russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae)]-infested and uninfested plants. mg-de ... | 2004 | 15154496 |
| aphid (hemiptera: aphididae) resistance in wheat near-isogenic lines. | plant and aphid biomass, photosynthetic pigment (chlorophylls a and b and carotenoids) concentrations, and chlorophyll a/b and chlorophyll/carotenoid ratios were quantified in aphid-infested 'tugela' near-isogenic lines (tugela, tugela-dn1, tugela-dn2, and tugela-dn5). the objectives were to quantify changes of photosynthetic pigments (chlorophylls a and b, and carotenoids) caused by aphid feeding and assess resistance of wheat isolines through aphid and plant biomass analysis. biomass of bird c ... | 2004 | 15154494 |
| comparative biology of a novel strain of russian wheat aphid (homoptera: aphididae) on three wheat cultivars. | in spring 2003, several outbreaks of the russian wheat aphid, diuraphis noxia (mordvilko), were reported in fields of supposedly resistant wheat cultivars ('stanton', 'halt', and 'prairie red') in eastern colorado. we conducted two laboratory experiments to compare the biological performance of this new biotype 2 (b2) to that of two d. noxia collections of biotype 1 (b1) from western kansas by using three wheat cultivars as host plants: 'trego', a susceptible cultivar, and stanton and halt, two ... | 2005 | 16022336 |
| resistance to rhopalosiphum padi (homoptera: aphididae) in three triticale accessions. | experiments were conducted to identify and characterize host plant resistance to bird cherry-oat aphid, rhopalosiphum padi (l.), in various wheat and wheat-grass hybrids. initial tests screened for resistance to r. padi among 12 grass accessions (eight wheat [triticum aestivum l.], three triticale [xtriticosecale wittmack], and 1xelytricum [elytrigia elongata [host] nevski x triticum aestivum hybrid]). r. padi had less population growth on triticale accessions '8ta5l' (pi 611760) and 'stniism 3' ... | 2005 | 15889754 |
| yield response and categories of resistance to russian wheat aphid in four dn4 hard red winter wheat cultivars. | a field experiment was conducted to determine whether resistance to russian wheat aphid, diuraphis noxia (mordvilko), conferred by the dn4 gene is affected by genetic background. this was done by comparing the yield responses to russian wheat aphid-resistant wheat containing dn4, derived through the backcross method, to those of the corresponding recurrent parents. infested resistant cultivars had fewer russian wheat aphids per tiller than infested susceptible cultivars at the lamar and fort col ... | 2005 | 15889752 |
| influence of three resistance sources in winter wheat derived from tam 107 on yield response to russian wheat aphid. | a study to determine yield response to the russian wheat aphid, diuraphis noxia (mordvilko), was conducted during the 1997-1998 and 1998-1999 growing seasons at three eastern colorado locations, akron, fort collins, and lamar, with three wheat lines containing either russian wheat aphid-resistant dn4 gene, dn6 gene, or resistance derived from pi 222668, and tam 107 as the susceptible control. russian wheat aphids per tiller were greater on tam 107 than the resistant wheat lines at the 10x infest ... | 2005 | 15889729 |
| interactions among three species of cereal aphids simultaneously infesting wheat. | interactions among greenbug, schizaphis graminum (rondani), russian wheat aphid, diuraphis noxia (mordvilko), and bird cherry-oat aphid rhopalosiphum padi (l.) were examined on wheat plants (triticum aestivum l., cultivar tam 107). nymphs were released on the plants as conspecific and heterospecific pairs of either first or fourth instars and evaluated for survival, developmental time, fecundity, intra-plant movement, and affinity to plant tissues. survival from first instar to onset of reproduc ... | 2005 | 16341245 |
| comparison of dn4- and dn7-carrying spring wheat genotypes artificially infested with russian wheat aphid (homoptera: aphididae) biotype 1. | genetic resistance is a useful control strategy for managing russian wheat aphid, diuraphis noxia (mordvilko), in wheat, triticum aestivum l. in 2003, a russian wheat aphid population (denoted as biotype 2) identified in colorado was virulent to genotypes carrying the dn4 russian wheat aphid resistance gene, necessitating the rapid identification and deployment of new sources of resistance. although the dn7 gene had shown excellent resistance to russian wheat aphid biotypes 1 and 2 in evaluation ... | 2005 | 16334342 |
| is photosynthetic transcriptional regulation in triticum aestivum l. cv. 'tugeladn' a contributing factor for tolerance to diuraphis noxia (homoptera: aphididae)? | diuraphis noxia (russian wheat aphid, rwa) is a major pest on wheat in south africa and most other wheat growing countries. being a probing-sucking insect, rwas insert their stylets into the phloem sieve elements and feed on the phloem sap. this feeding causes necrotic lesions in resistant varieties, or decoloration of leaves and death in susceptible varieties. in an effort to broaden our understanding on the response of the plant to rwa feeding, we synthesized and analyzed expressed sequence ta ... | 2006 | 16328390 |
| response of resistant and susceptible barley to infestations of five diuraphis noxia (homoptera: aphididae) biotypes. | since 2003, four new biotypes of the russian wheat aphid, diuraphis noxia (kurdjumov) (homoptera: aphididae), rwa2-rwa5, have been discovered that have the ability to damage most of the wheat germplasm resistant to the original russian wheat aphid population (rwa1). barley germplasm lines with resistance to rwa1 have not yet been evaluated against the newest biotypes. our study compared how biotypes rwa1-rwa5 affected the growth and leaf damage of rwa1-resistant germplasm (stars 9301b, stars 957 ... | 2006 | 17195687 |
| biotypic variation among north american russian wheat aphid (homoptera: aphididae) populations. | the russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae), has been a major economic pest of small grains in the western united states since its introduction in 1986. recently, a new russian wheat aphid biotype was discovered in southeastern colorado that damaged previously resistant wheat, triticum aestivum l. biotype development jeopardizes the durability of plant resistance, which has been a cornerstone for russian wheat aphid management. our objective was to assess the rela ... | 2006 | 17066823 |
| categories and inheritance of resistance to russian wheat aphid (homoptera: aphididae) biotype 2 in a selection from wheat cereal introduction 2401. | the russian wheat aphid, diuraphis noxia (kurdjumov) (homoptera: aphididae), is one of the most devastating insect pests of wheat (triticum spp.) and barley (hordeum spp.) in the world. yield losses and control costs are valued at several hundred million dollars each year. the use of d. noxia-resistant cultivars is an ecologically, economically, and biologically sound method of managing this pest. several d. noxia resistance (dn) genes from wheat have been used to develop cultivars resistant to ... | 2006 | 17066822 |
| the reactive oxygen species are involved in resistance responses of wheat to the russian wheat aphid. | the effect of russian wheat aphid (rwa), diuraphis noxia (mordvilko), infestation on the hydrogen peroxide (h(2)o(2)) content and nadph oxidase (ec 1.6.3.1) activity was studied in the resistant (cv. tugela dn) and near-isogenic susceptible (cv. tugela) wheat (triticum aestivum l.). the objective of this study was to investigate the involvement of the reactive oxygen species (ros) during the resistance responses against the rwa. infestation significantly induced an early accumulation of the h(2) ... | 2006 | 17032617 |
| molecular basis of plant gene expression during aphid invasion: wheat pto- and pti-like sequences are involved in interactions between wheat and russian wheat aphid (homoptera: aphididae). | the russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae), is a major pest of bread wheat, triticum aestivum l. (em thell), in most wheat-growing areas worldwide. aphid-resistant cultivars are used to combat this pest, but very little is known about the molecular basis of resistance. in this study, differential gene expression in d. noxia biotype 1-resistant wheat plants containing the dnx gene and d. noxia biotype 1 feeding on dnx plants was investigated using suppressive subt ... | 2006 | 16937702 |
| positive correlation of fitness with group size in two biotypes of russian wheat aphid (homoptera: aphididae). | changes in fitness parameters as a function of colony size (one versus 10 aphids) were measured in two biotypes (rwa1 and rwa2) of the russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae), feeding on three cultivars of wheat, triticum aestivum l., at two temperatures. 'trego' is a cultivar with no specific resistance to d. noxia, whereas, 'stanton' and 'halt' express dny and dn4 resistance sources, respectively. feeding in a group accelerated the development of rwa1 on trego a ... | 2006 | 16937675 |
| diuraphis noxia and rhopalosiphum padi (hemiptera: aphididae) interactions and their injury on resistant and susceptible cereal seedlings. | interspecific interactions between the symptomatic (chlorosis-eliciting) russian wheat aphid, diuraphis noxia (mordvilko), and the asymptomatic (nonchlorosis-eliciting) bird cherry-oat aphid, rhopalosiphum padi (l.), on four cereal genotypes were examined by simultaneous infestations. four cereals (i.e., diuraphis noxia-susceptible 'arapahoe' wheat and 'morex' barley, and d. noxia-resistant 'halt' wheat and 'border' oat) and four infestations (i.e., control, d. noxia, r. padi, and d. noxia/r. pa ... | 2006 | 16686159 |
| resistance to biotype 2 russian wheat aphid (homoptera: aphididae) in two wheat lines. | biotype 2 of the russian wheat aphid, diuraphis noxia (mordvilko), was identified in the united states in 2003 and is virulent to all commercially available cultivars of winter wheat, triticum aestivum l., that are resistant to biotype 1. we compared the development and reproduction of biotype 2 d. noxia at 21.7 +/- 0.12 degrees c on 'trego' (pi 612576), a susceptible commercial cultivar, and on lines ci 2401 and 03gd1378027 that represent putative resistance sources. ci 2401 is a pure wheat lin ... | 2006 | 16686158 |
| physiological and biochemical responses of resistant and susceptible wheat to injury by russian wheat aphid. | we examined the physiological and biochemical responses of resistant ('halt' and 'prairie red') and susceptible ('tam 107') wheat, triticum aestivum l., to injury by the russian wheat aphid, diuraphis noxia (mordvilko). photosynthetic capacity was evaluated by measuring assimilation/internal co2 (a/ci) curves, chlorophyll fluorescence, chlorophyll, and nonstructural carbohydrate content. total protein and peroxidase specific activity also were determined. no significant differences were detected ... | 2007 | 17972650 |
| variation to cause host injury between russian wheat aphid (homoptera: aphididae) clones virulent to dn4 wheat. | biotypes are infraspecific classifications based on biological rather than morphological characteristics. cereal aphids are managed primarily by host plant resistance, and they often develop biotypes that injure or kill previously resistant plants. although molecular genetic variation within aphid biotypes has been well documented, little is known about phenotypic variation, especially virulence or the biotype's ability to cause injury to cultivars with specific resistance genes. five clones (si ... | 2007 | 17972649 |
| distribution and diversity of russian wheat aphid (hemiptera: aphididae) biotypes in north america. | wheat, triticum aestivum l., with russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae) resistance based on the dn4 gene has been important in managing russian wheat aphid since 1994. recently, five biotypes (rwa1-rwa5) of this aphid have been described based on their ability to differentially damage rwa resistance genes in wheat. rwa2, rwa4, and rwa5 are of great concern because they can kill wheat with dn4 resistance. in 2005, 365 russian wheat aphid clone colonies were made ... | 2007 | 17972648 |
| fractionated extracts of russian wheat aphid eliciting defense responses in wheat. | it is hypothesized that the interaction between aphids and plants follows a gene-for-gene model. the recent appearance of several new russian wheat aphid, diuraphis noxia (kurdjumov) (homoptera: aphididae), biotypes in the united states and the differential response of wheat, triticum aestivum l., genotypes containing different resistance genes also suggest a gene-for-gene interaction. however, aphid elicitors remain unknown. this study was conducted to identify fractionated russian wheat aphid ... | 2007 | 17598566 |
| cross-species transferability of microsatellite markers from six aphid (hemiptera: aphididae) species and their use for evaluating biotypic diversity in two cereal aphids. | the abundance and distribution of microsatellites, or simple sequence repeats (ssrs) were explored in the expressed sequence tag (est) and genomic sequences of the pea aphid, acyrthosiphon pisum (harris), and the green peach aphid, myzus persicae (sulzer). a total of 108 newly developed, together with 40 published, ssr markers were investigated for their cross-species transferability among six aphid species. genetic diversity among six greenbug, schizaphis graminum (rondani) and two russian whea ... | 2007 | 17714463 |
| molecular phylogenetics and reproductive incompatibility in a complex of cryptic species of aphid parasitoids. | we infer the phylogeny of a complex of cryptic species and populations of parasitic wasps and examine how reproductive incompatibility maps onto the molecular phylogeny. we used four nuclear (28s-d2, its1, its2, argk) and two mitochondrial (coi, coii) gene regions to analyze relationships among populations in the aphelinus varipes species complex (hymenoptera: aphelinidae) from throughout eurasia (france, georgia, israel, china, korea and japan) and from three aphid hosts (aphis glycines, diurap ... | 2007 | 17702609 |
| sipha maydis: distribution and host range of a new aphid pest of winter cereals in argentina. | sipha maydis (passerini) is a new aphid pest of cereals and cultivated and wild grasses in argentina. this species was recently introduced into america, and nothing is known of its distribution or host range in south america. a better understanding of its biology is likely to facilitate control. this article records 1) the distribution and 2) the host range of s. maydis in argentina. over the period 2004-2006 samples were collected from 32 populations at several localities in argentina. the numb ... | 2007 | 18232394 |
| reproductive rates of russian wheat aphid (hemiptera: aphididae) biotypes 1 and 2 on a susceptible and a resistant wheat at three temperature regimes. | the reproductive rates of russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), biotype 1 (rwa 1) and biotype 2 (rwa 2) were compared in the laboratory at three temperature regimes on a russian wheat aphid resistant cultivar ('prairie red') and a susceptible cultivar ('tam 107'). the objective of this study was to expose rwa 1 and rwa 2 to three temperature regimes and two levels of resistance to find whether there were reproductive differences that may occur within each bioty ... | 2008 | 18613599 |
| biotypic diversity in colorado russian wheat aphid (hemiptera: aphididae) populations. | the biotypic diversity of the russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), was assessed in five isolates collected in colorado. three isolates, rwa 1, rwa 2, and an isolate from montezuma county, co, designated rwa 6, were originally collected from cultivated wheat, triticum aestivum l., and obtained from established colonies at colorado state university. the fourth isolate, designated rwa 7, was collected from canada wildrye, elymus canadensis l., in baca county, co. ... | 2008 | 18459426 |
| reproduction and development of russian wheat aphid biotype 2 on crested wheatgrass, intermediate wheatgrass, and susceptible and resistant wheat. | the russian wheat aphid, diuraphis noxia (kurdjumov), is an economically important pest of small grains. since its introduction into north america in 2003, russian wheat aphid biotype 2 has been found to be virulent to all commercially available winter wheat, triticum aestivum l., cultivars. our goal was to examine differences in russian wheat aphid reproduction and development on a variety of plant hosts to gain information about 1) potential alternate host refuges, 2) selective host pressures ... | 2008 | 18459422 |
| antioxidative enzymes and the russian wheat aphid (diuraphis noxia) resistance response in wheat (triticum aestivum). | a crucial function of antioxidative enzymes is to remove excess reactive oxygen species (ros), which can be toxic to plant cells. the effect of russian wheat aphid (rwa), diuraphis noxia (mordvilko), infestation on the activities of antioxidative enzymes was investigated in the resistant (cv. tugela dn) and the near-isogenic susceptible (cv. tugela) wheat (triticum aestivum l.). rwa infestation significantly induced the activity of superoxide dismutase, glutathione reductase and ascorbate peroxi ... | 2008 | 18426488 |
| glycoproteins from russian wheat aphid infested wheat induce defence responses. | elicitors are molecules which can induce the activation of plant defence responses. elicitor activity of intercellular wash fluid from russian wheat aphid, diuraphis noxia (mordvilko) infested resistant (cv tugela dn), and susceptible (cv tugela), wheat (triticum aestivum l.), was investigated. known russian wheat aphid resistance related responses such as peroxidase and beta-1,3-glucanase activities were used as parameters of elicitor activity. the intercellular wash fluid from infested resista ... | 2009 | 12440726 |
| microsatellite-based molecular diversity of bread wheat germplasm and association mapping of wheat resistance to the russian wheat aphid. | genetic diversity of a set of 71 wheat accessions, including 53 biotype 2 russian wheat aphid (rwa2)-resistant landraces and 18 rwa2 susceptible accessions, was assessed by examining molecular variation at multiple microsatellite (ssr) loci. fifty-one wheat ssr primer pairs were used, 81 ssr loci were determined, and 545 ssr alleles were detected. these ssr loci covered all the three genomes, 21 chromosomes, and at least 41 of the 42 chromosome arms. diversity values averaged over ssr loci were ... | 2009 | 18392559 |
| inheritance and categories of resistance in wheat to russian wheat aphid (hemiptera: aphididae) biotype 1 and biotype 2. | the russian wheat aphid, diruaphis noxia (kudjumov) (hemiptera: aphididae), is globally one of the most devastating pests of wheat, tritium aestivum l., and barley, hordeum vulgare l. host plant resistance is the foundation of cereal insect pest management programs, and several d. noxia resistance (dn) genes from wheat have been introduced in commercial cultivars of wheat to manage russian wheat aphid (rwa). emergence of d. noxia biotype 2 (rwa2) in colorado has made all known dn genes, except t ... | 2009 | 19736781 |
| limited genetic variation within and between russian wheat aphid (hemiptera: aphididae) biotypes in the united states. | insect biotypes are populations able to kill or injure crops with resistance genes and complicate pest management programs based on host plant resistance. biotypes occur in russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), a worldwide pest of wheat, triticum aestivum l., and barley, hordeum vulgare l., that was introduced into mexico in 1980 and then spread into texas by 1986. five d. noxia biotypes were described in the united states and given the number designations 1 th ... | 2009 | 19253666 |
| plant responses to seven russian wheat aphid (hemiptera: aphididae) biotypes found in the united states. | the russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), is a serious wheat, triticum aestivum l., and barley, hordeum vulgare l., pest throughout the small grain-producing areas in the western united states. the virulency and classification of recently described russian wheat aphid biotypes 1-7 (rwa1-7) were clarified using 24 plant differentials. these seven biotypes had been described previously using various methods and test environments; therefore, the purpose of this st ... | 2009 | 19886462 |
| aphid resistance in wheat varieties. | as an environmentally compatible alternative to the use of conventional insecticides to control cereal aphids, we have investigated the possibility to exploit natural resistance to insect pests in wheat varieties. we have tested a wide range of hexaploid (triticum aestivum), tetraploid (t. durum) and diploid (t. boeoticum and t. monococcum) wheat lines for resistance to the bird cherry oat aphid (rhopalosiphum padi). lines tested included russian wheat aphid (diuraphis noxia), greenbug (schizaph ... | 2009 | 20218532 |
| diuraphis noxia reproduction and development with a comparison of intrinsic rates of increase to other important small grain aphids: a meta-analysis. | the russian wheat aphid, diuraphis noxia (kurdjumov), is a significant pest of small grains in the united states and worldwide. there is an increasing need for quality population dynamic models to aid in development of integrated pest management strategies. unfortunately, there exists high variability in published data regarding basic life history traits that frequently direct model parameterization. metadata were analyzed to develop relationships between temperature and reproductive and develop ... | 2009 | 19689884 |
| feeding behavior of russian wheat aphid (hemiptera: aphididae) biotype 2 in response to wheat genotypes exhibiting antibiosis and tolerance resistance. | in this study, wheat, triticum aestivum l. (em thell), genotypes containing the dnx, dn7, dn6, and dn4 genes for resistance to the russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), along with dn0, a susceptible control, were assessed to determine the categories of d. noxia biotype 2 (rwa2) resistance in each genotype and rwa2 feeding behaviors on dnx and dn0 plants by using the electronic penetration graph technique. at 14 d postinfestation, dn0 plants exhibited intense ch ... | 2009 | 19610450 |
| resistance to russian wheat aphid biotype 2 in cimmyt synthetic hexaploid wheat lines. | the russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), devastates wheat and barley production on all continents except australia. although d. noxia-resistant cultivars exist, virulent d. noxia populations exist in asia, north america, and south america that have the ability to overcome resistance. in this study, synthetic hexaploid wheat genotypes created at the international maize and wheat improvement center (cimmyt) were evaluated and characterized for resistance to nort ... | 2009 | 19610446 |
| dissimilar molecular defense responses are elicited in triticum aestivum after infestation by different diuraphis noxia biotypes. | for sustainable solutions to the problem of insect infestation, the study of molecular plant-insect interactions is integral to resistance breeding strategies. this also holds true in the case of wheat (triticum aestivum), where the russian wheat aphid (diuraphis noxia, kurdjumov, rwa) is responsible for significant crop losses in most major wheat producing countries around the world. our study is focused on gaining a greater understanding of the resistance mechanisms activated by the rwa resist ... | 2009 | 19453509 |
| modeling spatial variation of russian wheat aphid overwintering population densities in colorado winter wheat. | the russian wheat aphid, diuraphis noxia (kurdjumov), is a pest of small grain crops that has caused hundreds of millions of dollars of damage since it was first reported in the united states in 1986. much is known about d. noxia population dynamics during the spring and early summer when most of the crop damage occurs, whereas little is known about the system during the overwintering period. using a spatially explicit model developed from field observations in a wheat/fallow agro-ecosystem, we ... | 2009 | 19449632 |
| molecular cytogenetic and agronomic characterization of advanced generations of wheat x triticale hybrids resistant to diuraphis noxia (mordvilko): application of gish and microsatellite markers. | the pi 386148 triticale from russia is among the highest resistant line to the russian wheat aphid (rwa) (diuraphis noxia (mordvilko)). this triticale line was used as the male parent in crosses with lamar wheat (triticum aestivum l.). the f1 plants were backcrossed to lamar wheat. the progenies were tested for rwa biotype 1 reaction for at least eight backcross and selfing generations. five lines from these selections were identified for their resistance to the rwa and their seeds were increase ... | 2009 | 19370091 |
| impact of diuraphis noxia and rhopalosiphum padi (hemiptera: aphididae) on primary physiology of four near-isogenic wheat lines. | the impact of feeding injury by the russian wheat aphid, diuraphis noxia (mordvilko) (hemiptera: aphididae), and bird cherry-oat aphid, rhopalosiphum padi (l.) (hemiptera: aphididae) on susceptible and resistant wheat, triticum aestivum l., near-isogenic lines 'tugela' (susceptible), tugela-dn1 (antibiotic), tugela-dn2 (tolerant), and tugela-dn5 (antixenotic) was evaluated by assessing photosynthetic parameters. photosynthesis and closely related parameters, pigment composition, and nonstructura ... | 2009 | 19253663 |
| a new modelling approach to insect reproduction with same-shape reproduction distribution and rate summation: with particular reference to russian wheat aphid. | same-shape distribution model and rate summation approach are widely used to describe the insect developmental process. in this approach, by integrating a nonlinear deterministic developmental rate model and a probabilistic same-shape distribution model, the proportion of the cohort completing development is quantified as a function of accumulating developmental rates, which themselves are temperature dependent. this method is considered to be more accurate in modelling insect phenology because ... | 2009 | 19159500 |
| stronger induction of callose deposition in barley by russian wheat aphid than bird cherry-oat aphid is not associated with differences in callose synthase or beta-1,3-glucanase transcript abundance. | the effects of infestation by the bird cherry-oat aphid (bca), (rhopalosiphum padi l) and the russian wheat aphid (rwa) (diuraphis noxia mordvilko) on callose deposition and transcription of genes related to callose accumulation were investigated in barley (hordeum vulgare l. cv. clipper). the bca, which gives no visible symptoms, induced very limited callose deposition, even after 14 days of infestation. in contrast, rwa, which causes chlorosis, white and yellow streaking and leaf rolling, indu ... | 2009 | 19055542 |
| gene expression profiling of tolerant barley in response to diuraphis noxia (hemiptera: aphididae) feeding. | aphids are, arguably, the single most damaging group of agricultural insect pests throughout the world. plant tolerance, which is a plant response to an insect pest, is viewed as an excellent management strategy. developing testable hypotheses based on genome-wide and more focused methods will help in understanding the molecular underpinnings of plant tolerance to aphid herbivory. as a first step in this process, we undertook transcript profiling with affymetrix genechip barley genome arrays usi ... | 2009 | 18840314 |
| host associations and incidence of diuraphis spp. in the rocky mountain region of the united states, and pictorial key for their identification. | the russian wheat aphid, diuraphis noxia kurdjumov, is an introduced species first identified in 1986 into the united states. it has since become a major pest of wheat, triticum aestivum l., and other small grains in the western united states. three other diuraphis species, diuraphis frequens (walker), diuraphis mexicana (mcvicar baker), and diuraphis tritici (gillette), were already endemic to the united states before the introduction of d. noxia. the objective of this study was to determine th ... | 2010 | 21061992 |
| virus-induced gene silencing of wrky53 and an inducible phenylalanine ammonia-lyase in wheat reduces aphid resistance. | although several wheat genes differentially expressed during the russian wheat aphid resistance response have recently been identified, their requirement for and specific role in resistance remain unclear. progress in wheat-aphid interaction research is hampered by inadequate collections of mutant germplasm and difficulty in transforming hexaploid wheat. virus-induced gene silencing (vigs) technology is emerging as a viable reverse genetics approach in cereal crops. however, the potential of vig ... | 2010 | 20561246 |
| limited endosymbiont variation in diuraphis noxia (hemiptera: aphididae) biotypes from the united states and south africa. | symbiosis allows an insect access to imbalanced food sources on which other organisms cannot survive. a bacterial endosymbiont, buchnera aphidicola, gives aphids the ability to feed on phloem depleted of certain essential amino acids by producing those required. pseudogenes and lower plasmid copy numbers of essential amino acid genes in b. aphidicola, endosymbiont of the russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae), suggest that this symbiotic relationship is degenerat ... | 2010 | 20568636 |
| differential regulation of 3-aminomethylindole/n-methyl-3-aminomethylindole n-methyltransferase and gramine in barley by both biotic and abiotic stress conditions. | the expression of nmt (3-aminomethylindole/n-methyl-3-aminomethylindole n-methyltransferase; ec 2.1.1.), involved in the biosynthesis of the indole alkaloid gramine, was investigated in aphid-infested barley (hordeum vulgare l.). nmt is induced by methyl jasmonate and it was hypothesized that the gene would be more strongly upregulated in aphid-resistant barley. we examined the effects of feeding by three aphid species; russian wheat aphid (diuraphis noxia mordvilko), rose-grain aphid (metopolop ... | 2010 | 21074448 |
| variation of resistance in barley against biotypes 1 and 2 of the russian wheat aphid (hemiptera: aphididae). | the russian wheat aphid, diruaphis noxia (kurdjumov) (hemiptera: aphididae), is globally one of the most devastating pests of bread wheat, tritium aestivum l.; durum wheat, triticum turgidum l.; and barley, hordeum vulgare l. host plant resistance is the foundation for cereal insect pest management programs, and several sources of d. noxia resistance have been incorporated in cultivars to manage d. noxia damage. the emergence of d. noxia north american biotype 2 (rwa2) in colorado has made all k ... | 2010 | 20568641 |
| inhibition of xanthine oxidase activity results in the inhibition of russian wheat aphid-induced defense enzymes. | the role of xanthine oxidase (xo) in the defense response of wheat (triticum aestivum l.) against the russian wheat aphid (rwa) (diuraphis noxia) was studied. xanthine oxidase catalyzes the oxidation of hypoxanthine to xanthine to uric acid, and oxygen radicals that are formed as a by-product at both of these oxidation steps may participate in plant defense reactions. a resistant wheat cultivar (tugela dn), and a close isogenic susceptible cultivar (tugela), were infested with 20-30 aphids per p ... | 2010 | 21086025 |
| transcript profiling of wheat genes expressed during feeding by two different biotypes of diuraphis noxia. | diuraphis noxia (kurdjumov)(russian wheat aphid) has severe economic impacts on wheat and barley production in the united states. the interaction between the russian wheat aphid and its cereal hosts is poorly understood. however, the recent appearance of new biotypes in the united states showed that specific interactions exist between wheat resistance loci and russian wheat aphid biotypes. at present, dn7 is the only known gene in hexaploid wheat that confers resistance against all u.s. russian ... | 2010 | 22127172 |
| global phylogenetics of diuraphis noxia (hemiptera: aphididae), an invasive aphid species: evidence for multiple invasions into north america. | the russian wheat aphid, diruaphis noxia (kudjumov) (hemiptera: aphididae), is globally one of the most devastating pests of bread wheat, tritium aestivum l., durum wheat, triticum turgidum l., and barley, hordeum vulgare l. several sources of d. noxia resistance have been incorporated in commercial wheat and barley genotypes, but up to eight virulent biotypes, defined based on their ability to damage different wheat and barley genotypes, now occur across the western united states since the firs ... | 2010 | 20568643 |
| aphid feeding activates expression of a transcriptome of oxylipin-based defense signals in wheat involved in resistance to herbivory. | damage by the russian wheat aphid (rwa), diuraphis noxia, significantly reduces wheat and barley yields worldwide. in compatible interactions, virulent rwa populations flourish and susceptible plants suffer extensive leaf chlorophyll loss. in incompatible interactions, rwa reproduction and population growth are significantly reduced and rwa-related chlorophyll loss in resistant plants is minor. the objectives of this study were to develop an understanding of the molecular and phytochemical bases ... | 2010 | 20229216 |
| salivary proteins of russian wheat aphid (hemiptera: aphididae). | salivary secretions play critical roles in aphid-host plant interactions and are responsible for damage associated with aphid feeding. the objectives of this study were to evaluate aspects of salivation and the salivary constituents of diuraphis noxia (hemiptera: aphididae). salivary proteins were isolated and compared from three aphid probed diets: pure water, 15% sucrose, or amino acids (100 mm serine, 100 mm methionine, 100 mm aspartic acid, and 15% sucrose). after 6 h, more aphids settled on ... | 2010 | 20146860 |
| survival analysis approach to insect life table analysis and hypothesis testing: with particular reference to russian wheat aphid (diuraphis noxia (mordvilko)) populations. | the goal of this paper is to examine and demonstrate that survival analysis, which has been a de facto standard in biomedical research since the 1990s but has not been widely adopted in entomology yet, should possess similar potential in entomological research. the following three objectives are set to achieve this goal: (i) addressing a fundamental issue - censoring or incomplete observations; (ii) demonstrating the application of survival analysis to analyze insect life tables; and (iii) apply ... | 2010 | 19941673 |
| distribution and diversity of russian wheat aphid (hemiptera: aphididae) biotypes in south africa and lesotho. | russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae) was recorded for the first time in south africa in 1978. in 2005, a second biotype, rwasa2, emerged, and here we report on the emergence of yet another biotype, found for the first time in 2009. the discovery of new russian wheat aphid biotypes is a significant challenge to the wheat, triticum aestivum l., industry in south africa. russian wheat aphid resistance in wheat, that offered wheat producers a long-term solution to ... | 2011 | 22066205 |
| wheat gene expression is differentially affected by a virulent russian wheat aphid biotype. | an improved understanding of the complex interactions between plants and aphids is emerging. recognition of aphid feeding in plant tissues involves production of several defense response signaling pathways and downstream production of defense and detoxification compounds. feeding by russian wheat aphid, diuraphis noxia (kurdjumov), a serious pest of cereal crops worldwide, induces foliar deformity and chlorophyll loss during compatible wheat-d. noxia interactions. experiments described here reve ... | 2011 | 21499720 |
| karyotype analysis of the russian wheat aphid, diuraphis noxia (kurdjumov) (hemiptera: aphididae) reveals a large x chromosome with rrna and histone gene families. | the russsian wheat aphid (rwa), diuraphis noxia (kurdjumov), is a worldwide pest of cereals. despite its economic importance, little is known about its genome. here we investigated physical genomic features in rwa by karyotype analysis using differential staining with agno(3), cma(3), and dapi, by chromosomal localization of ribosomal dna (rdna), h3 and h4 histone genes, and the "arthropod" telomeric sequence (ttagg)(n) using fluorescence in situ hybridization (fish), and by measuring the rwa ge ... | 2011 | 21336570 |