| nucleotide sequence analysis of the genomes of the mav-ps1 and p-pav isolates of barley yellow dwarf virus. | the mav-ps1 and p-pav isolates of barley yellow dwarf virus (bydv) are serologically related, but not identical. both are transmitted by the aphid macrosiphum avenae, but p-pav is also transmitted by rhopalosiphum padi. to evaluate the basis for these and other differences, overlapping clones from cdna libraries representing the genome of each isolate were characterized by restriction enzyme digestion and by hybridization, and subsequently sequenced. each genome has six positive strand open read ... | 1992 | 1538199 |
| a comparative study on the cell-free translation of the genomic rnas of two aphid picorna-like viruses. | the genomic rnas of aphid lethal paralysis virus (alpv) and rhopalosiphum padi virus (rhpv)--two distinct picorna-like viruses found in aphids [williamson et al. (1988) j gen virol 69: 787-795]--were both efficiently translated in rabbit reticulocyte lysates. alpv rna was translated into primary products with molecular weights ranging from 92 kda to 170 kda. these underwent time-dependent post-translational cleavage to produce smaller polypeptides including some with molecular weights comparable ... | 1989 | 2610597 |
| use of enzyme amplification in an elisa to increase sensitivity of detection of barley yellow dwarf virus in oats and in individual vector aphids. | a new technique of alkaline phosphatase amplification in an elisa (amplified elisa) was used to increase the sensitivity of detection of barley yellow dwarf virus (bydv) from oat plant sap and in individual vector aphids. amplified elisa differs from conventional direct double antibody sandwich elisa (das-elisa) in the enzyme substrate reaction. the bound enzyme-labelled antibody catalyzes the conversion of nadp to nad which is then used in a secondary enzyme-mediated cyclic reaction producing a ... | 1987 | 3558700 |
| variation within rhopalosiphum padi and transmission of barley yellow dwarf virus by clones of four aphid species. | | 1966 | 5919230 |
| discovery and molecular characterization of a plasmid localized in buchnera sp. bacterial endosymbiont of the aphid rhopalosiphum padi. | we have identified and completely sequenced a novel plasmid isolated from the aphid rhopalosiphum padi. evidence which suggests that the plasmid occurs localized within the bacterial endosymbionts is presented. the plasmid contains the four genes that constitute the entire leucine operon. this fact makes it really unique since most plasmids are dispensable and lack genes that encode essential anabolic functions. four more phloem-feeding aphid species also seem to contain homologous plasmids. alt ... | 1995 | 7608990 |
| molecular characterization of cyclic and obligate parthenogens in the aphid rhopalosiphum padi (l.). | holocyclic clones of the aphid rhopalosiphum padi (l.) reproduce by cyclic parthenogenesis, whereas anholocyclic individuals are obligate parthenogens. mitochondrial dna and (mtdna) and random amplified polymorphic dna markers in r. padi as well as plasmid dna markers of its bacterial endosymbiont, buchnera aphidicola, were examined to determine the extent of genetic divergence between clones with these differing breeding systems. these analyses revealed that cyclically parthenogenetic lineages ... | 1996 | 8637928 |
| the tryptophan biosynthetic pathway of aphid endosymbionts (buchnera): genetics and evolution of plasmid-associated anthranilate synthase (trpeg) within the aphididae. | the bacterial endosymbionts (buchnera) from the aphids rhopalosiphum padi, r. maidis, schizaphis graminum, and acyrthosiphon pisum contain the genes for anthranilate synthase (trpeg) on plasmids made up of one or more 3.6-kb units. anthranilate synthase is the first as well as the rate-limiting enzyme in the tryptophan biosynthetic pathway. the amplification of trpeg on plasmids may result in an increase of enzyme protein and overproduction of this essential amino acid, which is required by the ... | 1996 | 8642610 |
| in vitro interactions of the aphid endosymbiotic syml chaperonin with barley yellow dwarf virus. | barley yellow dwarf virus (bydv)-vector relationships suggest that there are specific interactions between bydv virions and the aphid's cellular components. however, little is known about vector factors that mediate virion recognition, cellular trafficking, and accumulation within the aphid. symbionins are molecular chaperonins produced by intracellular endosymbiotic bacteria and are the most abundant proteins found in aphids. to elucidate the potential role of symbionins in bydv transmission, w ... | 1997 | 8985385 |
| genotypic variation among different phenotypes within aphid clones. | most aphid species hemiptera: aphididae are parthenogenetic between periods of sexual reproduction. they are also highly polyphenic, with different adult morphs occurring in the life cycle, piz. winged, wingless, asexual and sexual. it is assumed that aphids born in a parthenogenetic clonal lineage are genetically identical regardless of the final adult form with the exception of sexual forms). using the randomly amplified polymorphic dna-polymerase chain reaction (rapd-pcr) we have found that d ... | 1997 | 9178543 |
| putative evolutionary origin of plasmids carrying the genes involved in leucine biosynthesis in buchnera aphidicola (endosymbiont of aphids). | an 8.5-kb plasmid encoding genes (leuabcd) involved in leucine biosynthesis and a small plasmid of 1.74 kb of yet unknown function were found in the intracellular symbiont, buchnera aphidicola, of two divergent aphid species, thelaxes suberi and tetraneura caerulescens, respectively. the leuabcd-carrying plasmid (pbts1) was amplified from total aphid dna by inverse long pcr, using outwardly oriented oligonucleotide primers specific to leua. the resulting 8.2-kb pcr fragment as well as the 1.74-k ... | 1997 | 9244264 |
| nucleotide sequence analysis shows that rhopalosiphum padi virus is a member of a novel group of insect-infecting rna viruses. | rhopalosiphum padi virus (rhpv) is an aphid virus that has been considered a member of the picornaviridae based on physicochemical properties. the 10,011-nt polyadenylated rna genome of rhpv was completely sequenced. analysis of the sequence revealed the presence of two open reading frames (orfs). the predicted amino acid sequence of orf1, representing the first 6600 nt of the rhpv genome, showed significant similarity to the nonstructural proteins of several plant and animal rna viruses. direct ... | 1998 | 9527915 |
| comparison of the coat protein, movement protein and rna polymerase gene sequences of australian, chinese, and american isolates of barely yellow dwarf virus transmitted by rhopalosiphum padi. | barely yellow dwarf luteovirus-gpv (bydv-gpv) is a common problem in chinese wheat crops but is unrecorded elsewhere. a defining characteristic of gpv is its capacity to be transmitted efficiently by both schizaphis graminum and rhopaloshiphum padi. this dual aphid species transmission contrasts with those of bydv-rpv and bydv-sgv, globally distributed viruses, which are efficiently transmitted only by rhopaloshiphum padi and schizaphis graminum respectively. the viral rna sequences encoding the ... | 1998 | 9645205 |
| 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 |
| determining the nucleotide sequence and capsid-coding region of himetobi p virus: a member of a novel group of rna viruses that infect insects. | we determined the complete genome sequence of himetobi p virus (hipv), an insect picorna-like virus, which was isolated from the small brown planthopper, laodelphax striatellus. the genome of hipv consists of 9,275 nucleotides excluding the poly (a) tail, and contains two large open reading frames (orfs), which were separated by a 176-nucleotide noncoding region. the deduced amino acid sequence of the first orf contains core motifs of picornaviral helicase, protease, and rna-dependent rna polyme ... | 1999 | 10550677 |
| nucleotide sequence analysis of triatoma virus shows that it is a member of a novel group of insect rna viruses. | triatoma virus (trv) is the only virus described to date that infects triatomines, and has previously been considered to be a member of the family picornaviridae on the basis of physico-chemical properties. the genome of trv was sequenced completely (9010 nt). analysis of the sequence revealed the presence of two large open reading frames (orfs). the predicted amino acid sequence of orf1 (nt 549-5936) showed significant similarity to the non-structural proteins of several animal and plant rna vi ... | 2000 | 10725445 |
| analysis of the complete genome sequence of black queen-cell virus, a picorna-like virus of honey bees. | a virus with picorna-like biophysical properties was isolated from south african honey bees. on the basis of serology, it was identified as an isolate of black queen-cell virus (bqcv). nucleotide sequence analysis revealed an 8550 nt polyadenylated genome containing two large orfs. the 5'-proximal orf (orf 1) represented 4968 nt while the 3'-proximal orf (orf 2) represented 2562 nt. the orfs were separated by a 208 nt intergenic region and were flanked by a 657 nt 5'-untranslated region and a 15 ... | 2000 | 10900051 |
| 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 |
| analysis of the complete genome sequence of acute bee paralysis virus shows that it belongs to the novel group of insect-infecting rna viruses. | the complete genome sequence of acute bee paralysis virus (abpv) was determined. the 9470 nucleotide, polyadenylated rna genome encoded two open reading frames (orf1 and orf2), which were separated by 184 nucleotides. the deduced amino acid sequence of the 5' orf1 (nucleotides 605 to 6325) showed significant similarity to the rna-dependent rna polymerase, helicase, and protease domains of viruses from the picornavirus, comovirus, calicivirus, and sequivirus families, as well as to a novel group ... | 2000 | 11080493 |
| a tertiary structure model of the internal ribosome entry site (ires) for methionine-independent initiation of translation. | cricket paralysis-like viruses have a dicistronic positive-strand rna genome. these viruses produce capsid proteins through internal ribosome entry site (ires)-mediated translation. the ires element of one of these viruses, plautia stall intestine virus (psiv), forms a pseudoknot immediately upstream from the capsid coding sequence, and initiates translation from other than methionine. previously, we estimated that the ires element of psiv consists of seven stem-loops using the program mfold; ho ... | 2001 | 11233983 |
| immunological analysis of phloem sap of bacillus thuringiensis corn and of the nontarget herbivore rhopalosiphum padi (homoptera: aphididae) for the presence of cry1ab. | phloem sap of transgenic bacillus thuringiensis (bt) corn expressing a truncated form of the b. thuringiensis delta-endotoxin cry1ab, sap sucking aphids feeding on bt corn and their honeydew were analysed for presence of cry1ab using elisa. phloem sap of bt and non-bt corn was collected using a newly developed technique with a microcapillary being directly inserted into the phloem tubes. using this technique, no cry1ab was detected in the phloem sap. in contrast, measurable concentrations of cry ... | 2001 | 11298965 |
| seasonal abundance of aphids (homoptera: aphididae) in wheat and their role as barley yellow dwarf virus vectors in the south carolina coastal plain. | aphid (homoptera: aphididae) seasonal flight activity and abundance in wheat, triticum aestivum l., and the significance of aphid species as vectors of barley yellow dwarf virus were studied over a nine-year period in the south carolina coastal plain. four aphid species colonized wheat in a consistent seasonal pattern. greenbug, schizaphis graminum (rondani), and rice root aphid, rhopalosiphum rufiabdominalis (sasaki), colonized seedlingwheat immediately after crop emergence, with apterous colon ... | 2001 | 11332833 |
| nucleotide sequence of 3'-end of the genome of taura syndrome virus of shrimp suggests that it is related to insect picornaviruses. | taura syndrome disease, caused by taura syndrome virus (tsv), is one of the most important viral diseases of penaeid shrimp in the western hemisphere resulting in catastrophic disease epidemics in farmed shrimp. we have cloned and sequenced a 3278 bp cdna representing the 3' end of the tsv genome. sequence analyses revealed that frame + 2 had the longest open reading (orf) frame. this frame contained a 5'-terminal 19 non-coding bases followed by an orf from nucleotides 20 to 3053 (encoding 1011 ... | 2001 | 11448031 |
| the 5' untranslated region of rhopalosiphum padi virus contains an internal ribosome entry site which functions efficiently in mammalian, plant, and insect translation systems. | rhopalosiphum padi virus (rhpv) is one of several picorna-like viruses that infect insects; sequence analysis has revealed distinct differences between these agents and mammalian picornaviruses. rhpv has a single-stranded positive-sense rna genome of about 10 kb; unlike the genomes of picornaviridae, however, this genome contains two long open reading frames (orfs). orf1 encodes the virus nonstructural proteins, while the downstream orf, orf2, specifies the structural proteins. both orfs are pre ... | 2001 | 11581392 |
| the effect of natural enemies on the spread of barley yellow dwarf virus (bydv) by rhopalosiphum padi (hemiptera: aphididae). | the effects of two natural aphid enemies, adult coccinella septempunctata linneaus, a predator, and aphidius rhopalosiphi de stefani perez, a parasitoid, on spread of barley yellow dwarf virus (bydv) transmitted by the bird cherry-oat aphid, rhopalosiphum padi (linnaeus) were studied under laboratory conditions. predators or parasitoids were introduced to trays of durum wheat seedlings and the patterns of virus infection were observed after two, seven and 14 days of exposure. more plants were in ... | 2001 | 11587627 |
| [effects of volatiles from different trophic level on foraging behavior of aphidius avenae]. | the responses of female aphidius avenae to volatiles from undamaged wheat plant, sitobion avenae and rhopalosiphum padi, aphids-plant complexes and aphids damaged plant were investigated in wind tunnel and y-tube olfactometer. the volatiles from undamaged wheat plant, s. avenae and r. padi were much less attractive to a. avenae than those from aphids-plant complexes and aphids-damaged plant. although the parasitic rate was much lower, the r. padi-plant complexes and r. padi damaged plant were al ... | 2001 | 11758388 |
| sequence analysis and genomic organization of aphid lethal paralysis virus: a new member of the family dicistroviridae. | the complete nucleotide sequence of the genomic rna of an aphid-infecting virus, aphid lethal paralysis virus (alpv), has been determined. the genome is 9812 nt in length and contains two long open reading frames (orfs), which are separated by an intergenic region of 163 nt. the first orf (5' orf) is preceded by an untranslated leader sequence of 506 nt, while an untranslated region of 571 nt follows the second orf (3' orf). the deduced amino acid sequences of the 5' orf and 3' orf products resp ... | 2002 | 12466490 |
| [cloning and prokaryotic expression of viral binding protein(vbp) gene from endosybiotic bacterium of rhopalosiphum padi]. | viral binding protein gene from rhopalosiphum padi yangling biotype was amplified by pcr method and then cloned. the complete nucleotide sequence of the gene was determined, it has 1647 nucleotides encoding 548 amino acids. comparison showed this gene has 97% identity on nucleotide level with buchnera groel-am gene of rhopalosiphum padi american biotype, while has 97.4% identity on amino acid level was found between this two genes. the vbp gene was ligated into pbv221 and pet30a expression vecto ... | 2002 | 12557551 |
| in vivo activity of rhopalosiphum padi virus internal ribosome entry sites. | the rna genome of rhopalosiphum padi virus (rhpv), like other members of the dicistroviridae, contains two open reading frames that are preceded by internal ribosome entry sites (iress). to compare the activities of the two rhpv iress in insect cells, a system was established for the in vivo transcription and translation of plasmid templates containing the iress. in this system, the two rhpv iress directed initiation of translation from bicistronic plasmids with equal efficiency. competition was ... | 2003 | 12560574 |
| 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 |
| 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 |
| patterns of resistance to three cereal aphids among wheats in the genus triticum (poaceae). | forty-one accessions of wild and cultivated wheats belonging to 19 triticum species were tested in the field for resistance to three species of aphids, rhopalosiphum padi linnaeus, sitobion avenae fabricius and schizaphis graminum rondani. antibiotic resistance was estimated by the increase in biomass of aphids over 21 days on adult plants. overall resistance was estimated by the plant biomass lost due to aphid infestation. all three species of aphids survived and reproduced on all wheats, and r ... | 2003 | 12908918 |
| [niches analysis of three aphid populations on spring sowing maize]. | systematic analysis of aphid populations and niches patterns on spring sowing maize was carried out during 1998-1999 in the suburbs of chongqing. the results indicated that there were three aphid populations rhopalosiphum maidis fitch., rhopalosiphum padi linn. and sitobion avenae fabricius distributed on the spring sowing maize. the mixed aphid populations traded off during the growth period of spring sowing maize, and two peaks of quantitative counts were shown at the mid and last ten days of ... | 2003 | 14733003 |
| tillage impacts cereal-aphid (homoptera: aphididae) infestations in spring small grains. | we compared infestation levels of cereal aphids (homoptera: aphididae) in spring-seeded wheat and barley grown with and without preplant tillage for 8 site yr in eastern south dakota. crop residue covered approximately 25% of the soil surface with preplant tillage, whereas without preplant tillage 50% or more of surface residue was conserved. rhopalosiphum padi (l.) comprised nearly 90% of all cereal aphids sampled, and r. maidis (fitch), schizaphis graminum (rondani), and sitobion avenae (f.) c ... | 2003 | 14977117 |
| activity of aphids associated with lettuce and broccoli in spain and their efficiency as vectors of lettuce mosaic virus. | this research sought to identify the aphid virus vector species associated with lettuce and broccoli crops in spain, and to determine their population dynamics and ability to transmit lettuce mosaic virus (lmv). green tile traps and moericke yellow water-pan traps were used to monitor aphid flights during the spring and autumn growing seasons of 2001. aphid species feeding on lettuce were counted weekly. the transmission efficiencies of lmv were determined for the aphid species caught most frequ ... | 2004 | 15036838 |
| life history of the bird cherry-oat aphid, rhopalosiphum padi (homoptera: aphididae), on transgenic and untransformed wheat challenged with barley yellow dwarf virus. | the life history of rhopalosiphum padi (l.) was monitored on transgenic and untransformed (soft white winter wheat plants that were infected with barley yellow dwarf virus (bldv), noninfected, or challenged with virus-free aphids under laboratory conditions. two transgenic soft white winter wheat genotypes (103.1j and 126.02) derived from the parental variety lambert and expressing the barley yellow dwarf virus coat protein gene, and two untransformed varieties, virus-susceptible lambert and vir ... | 2004 | 15154437 |
| the rhopalosiphum padi virus 5' internal ribosome entry site is functional in spodoptera frugiperda 21 cells and in their cell-free lysates: implications for the baculovirus expression system. | cap-independent internal initiation of translation occurs on a number of viral and cellular mrnas and is directed by internal ribosome entry site (ires) elements. rhopalosiphum padi virus (rhpv) is a member of the dicistroviridae. these viruses have single-stranded, positive-sense rna genomes that contain two open reading frames, both preceded by ires elements. previously, the activity of the rhpv 5' utr ires has been demonstrated in mammalian, drosophila and wheat germ in vitro translation syst ... | 2004 | 15166440 |
| observation on the initial inoculum source and dissemination of entomophthorales-caused epizootics in populations of cereal aphids. | a total number of 1092 migratory alates were trapped from air in wheat grown area of yuanyang county, henan province from early april through may 2002 in order to confirm the source and dissemination of entomophthoralean inocula to cause epizootics of cereal aphids. those included 415 sitobion avenae, 642 rhopalosiphum padi, 22 metopolophium dirhodum, and 13 schizaphis graminum. the trapped alates were daily collected and individually reared for 7 days on wheat plants in laboratory. of those 341 ... | 2004 | 15382675 |
| [obtainment of transgenic wheat with the insecticidal lectin from snowdrop (galanthus nivalis agglutinin; gna) gene and analysis of resistance to aphid]. | snowdrop lectin (galanthus nivalis agglutinin; gna) is toxic to sap sucking injurious insects of homopteran. a new gna gene has been transferred into common spring wheat zhong60634 and winter wheat yumai66 with high yield by using the biolistic transformation method. transgenic wheat plants have been obtained in both of the two varieties. two transgenic plants (t0) have been obtained from the bombarded 535 immature embryos of zhong60634. bioassay results show that the development of aphid could ... | 2004 | 15473311 |
| ostrinia nubilalis parasitism and the field abundance of non-target insects in transgenic bacillus thuringiensis corn (zea mays). | in this study, we evaluated in field trials the effects on non-target species, of transgenic corn producing the cry1ab toxin of bacillus thuringiensis (bt). in 1998, we collected ostrinia nubilalis (hübner) larvae from transgenic bt corn (novartis hybrid 176) and non-bt corn at four geographical sites. we found a significant variation in parasitism by the tachinids lydella thompsoni (herting) and pseudoperichaeta nigrolineata (walker) among sites, and more parasitism in non-bt than in bt fields. ... | 2002 | 15612256 |
| admixed sexual and facultatively asexual aphid lineages at mating sites. | cyclically parthenogenetic organisms may have facultative asexual counterparts. such organisms, including aphids, are therefore interesting models for the study of ecological and genetic interactions between lineages differing in reproductive mode. earlier studies on aphids have revealed major differences in the genetic outcomes of populations that are possibly resulting mostly either from sexual or from asexual reproduction. besides, notable gene flow between sexual and asexual derivatives has ... | 2005 | 15643974 |
| variation in barley yellow dwarf virus transmission efficiency by rhopalosiphum padi (homoptera: aphididae) after acquisition from transgenic and nontransformed wheat genotypes. | the effects of different acquisition access periods (aaps) and inoculation access periods (iaps) on the transmission efficiency of barley yellow dwarf luteovirus (bydv) by rhopalosiphum padi (l.) (homoptera: aphididae) after feeding on transgenic or nontransformed wheat, triticum aestivum l., genotypes were studied. three wheat genotypes were tested as virus sources: virus-susceptible 'lambert' and 'lambert'-derived transgenic lines 103.1j and 126.02, which express the bydv-pav coat protein gene ... | 2004 | 15666729 |
| evaluation of oat cultivars and lines under infection with barley yellow dwarf virus. | thirteen domestic and foreign oat cultivars and eight breeding lines bred from the university of illinois were evaluated for resistance to barley yellow dwarf (byd) using artificial inoculation with rhopalosiphum padi viruliferous for an isolate of barley yellow dwarf virus-pav endemic to moscow region origin. cultivar blaze and six illinois lines showed the best grain yields under disease pressure that resembled a byd epidemic. | 2004 | 15756843 |
| economic evaluation of the effects of planting date and application rate of imidacloprid for management of cereal aphids and barley yellow dwarf in winter wheat. | the effects of planting date and application rate of imidacloprid for control of schizaphis graminum rondani, rhopalosiphum padi l. (homoptera: aphididae), and barley yellow dwarf virus (bydv) in hard red winter wheat were studied. the first experiment was conducted from 1997 to 1999 at two locations and consisted of three planting dates and four rates of imidacloprid-treated seed. the second experiment was conducted from 2001 to 2002 in stillwater, ok, and consisted of two varieties of hard red ... | 2005 | 15765670 |
| estimation of hymenopteran parasitism in cereal aphids by using molecular markers. | polymerase chain reaction (pcr) primers were designed and tested for identification of immature parasitoids in small grain cereal aphids and for estimation of parasitism rates. pcr technique was evaluated for 1) greenhouse-reared greenbugs, schizaphis graminum (rondani), parasitized by lysiphlebus testaceipes cresson and 2) aphids collected from winter wheat fields in caddo county, oklahoma. for greenhouse samples, parasitism frequencies for greenbugs examined by pcr at 0, 24, and 48 h after rem ... | 2005 | 15765686 |
| development of a bi-cistronic baculovirus expression vector by the rhopalosiphum padi virus 5' internal ribosome entry site. | a bi-cistronic baculovirus transfer vector was constructed based on the 5'utr internal ribosome entry site (ires) of the rhopalosiphum padi virus (rhpv). recombinant baculoviruses containing the red fluorescent protein gene and green fluorescent protein gene flanking the rhpv 5'utr ires can simultaneously produce dual fluorescence in recombinant virus-infected spodoptera frugiperda 21 cells (sf21) under the control of a polyhedrin promoter. quantization by fluorescence spectrophotometry of the f ... | 2005 | 16084836 |
| a simple wax-embedding method for isolation of aphid hemolymph for detection of luteoviruses in the hemocoel. | a protocol for isolating hemolymph from viruliferous aphids has been developed. this method uses warm melted wax to immobilize the aphid. following removal of a hind leg, the hemolymph can be collected readily. flushing with rnase-free water allows for collection of sufficient hemolymph for rna extraction from individual aphids. the extracted rna was successfully used for detection of barley yellow dwarf virus (bydv) and pea enation mosaic virus (pemv) from individual viruliferous rhopalosiphum ... | 2006 | 16307802 |
| insect feeding deterrents in endophyte-infected tall fescue. | the presence of an endophytic fungus, acremonium coenophialum, in tall fescue (festuca arundinacea) deterred aphid feeding by rhopalosiphum padi and schizaphis graminum. both species of aphid were unable to survive when confined to endophyte-infected tall fescue plants. feeding deterrents and toxic factors to r. padi and oncopeltus fasciatus, large milkweed bug, were primarily associated with a methanol extract obtained when endophyte-infected tall fescue seed was serially extracted with hexane, ... | 1985 | 16346751 |
| influence of aphid species and barley yellow dwarf virus on soft red winter wheat yield. | yield loss in soft red winter wheat, triticum aestivum l., caused by aphid-transmitted barley yellow dwarf virus (family luteoviridae, genus luteovirus, bydv) was measured over a 2-yr period in central missouri. rhopalosiphum padi (l.) was the most common and economically important species, accounting for > 90% of the total aphids. schizaphis graminum (rondani), rhopalosiphum maidis (fitch), and sitobion avenae (f.) made up the remainder of the aphids. aphid numbers peaked at wheat stem elongati ... | 2005 | 16539127 |
| insect infestations, incidence of viral plant diseases, and yield of winter wheat in relation to planting date in the northern great plains. | planting date effects on arthropod infestation and viral plant disease are undocumented for winter wheat, triticum aestivum l., in south dakota and the northern great plains. winter wheat was planted over three dates (early, middle, and late; generally from late august to late september) to determine the effect on abundance of insect pests, incidence of plant damage, incidence of viral plant disease, and grain yield. the study was conducted simultaneously at two sites in south dakota over three ... | 2005 | 16539128 |
| cloning and sequence analysis of 2 different acetylcholinesterase genes in rhopalosiphum padi and sitobion avenae. | two genes encoding different acetylcholinesterases (ache) were successfully cloned from 2 species of aphid, rhopalosiphum padi (l.) and sitobion avenae (f.). they were named rp.ache1 (genbank accession no. ay707318), rp.ache2 (ay667435), sa.ache1 (ay707319), and sa.ache2 (ay819704), and were 2133, 2363, 2131, and 2362 bp in length and encoded 664, 676, 664, and 676 amino acids, respectively. all of them shared the characteristics of the ache family: catalytic tiads, 3 intra-chain disulfide bridg ... | 2006 | 16604106 |
| fungal plant endosymbionts alter life history and reproductive success of aphid predators. | endosymbionts occur in most plant species and may affect interactions among herbivores and their predators through the production of toxic alkaloids. here, we ask whether effects of mycotoxins produced by the symbiosis of the fungal endophyte neotyphodium lolii and the grass lolium perenne are transmitted to the aphidophagous ladybird coccinella septempunctata when feeding on cereal aphids rhopalosiphum padi on infected plants. the larval development of coccinellids was extended, while their sur ... | 2006 | 16720406 |
| sources of variation in the interaction between three cereal aphids (hemiptera: aphididae) and wheat (poaceae). | the relative contributions of host plant, herbivore species and clone to variation in the interaction between cereal aphids and wheat were investigated using five clones each of three species, rhopalosiphum padi (linnaeus), sitobion avenae (fabricius) and schizaphis graminum (rondani), on seedlings of two cultivars of triticum aestivum l. and one cultivar of triticum durum desf. more individuals and biomass of r. padi than of the other two species were produced on seedlings. the three wheat cult ... | 2006 | 16768811 |
| comparing growth patterns among field populations of cereal aphids reveals factors limiting their maximum abundance. | cereal stands in central europe are commonly infested with three species of aphids that may become serious pests. with increasing abundance, the proportion of a particular species in the total aphid population may remain constant, suggesting a density-independent exponential growth, or the proportion can change, suggesting density-dependent constraints on growth. the constraints that affect particular species, and thus their relative abundance, were studied. the proportionality between maximum a ... | 2006 | 16768815 |
| genome reduction of the aphid endosymbiont buchnera aphidicola in a recent evolutionary time scale. | genome reduction, a typical feature of symbiotic bacteria, was analyzed in the last stages of evolution of buchnera aphidicola, the primary aphid endosymbiont, in two neutrally evolving regions: the pseudogene cmk and an intergenic region. these two regions were examined in endosymbionts from several lineages of their aphid host rhopalosiphum padi, and different species of the same genus, whose divergence times ranged from 0.62 to 19.51 million years. estimates of nucleotide substitution rates w ... | 2007 | 17098378 |
| characterization of the 5' internal ribosome entry site of plautia stali intestine virus. | the rna genome of plautia stali intestine virus (psiv; cripavirus, dicistroviridae) contains two open reading frames, the first of which is preceded by a 570 nt untranslated region (5' utr). the 5' utr was confirmed to be an internal ribosome entry site (ires) using an insect cell lysate translation system: translation of a second cistron increased 14-fold in the presence of the 5' utr and a cap analogue did not inhibit translation of the second cistron. deletion analysis showed that 349 bases c ... | 2006 | 17098985 |
| identification of minimal sequences of the rhopalosiphum padi virus 5' untranslated region required for internal initiation of protein synthesis in mammalian, plant and insect translation systems. | rhopalosiphum padi virus (rhpv) is a member of the family dicistroviridae. the genomes of viruses in this family contain two open reading frames, each preceded by distinct internal ribosome entry site (ires) elements. the rhpv 5' ires is functional in mammalian, insect and plant translation systems and can form 48s initiation complexes in vitro with just the mammalian initiation factors eif2, eif3 and eif1. large regions of the 5' untranslated region (utr) can be deleted without affecting initia ... | 2007 | 17412990 |
| mutations in acetylcholinesterase genes of rhopalosiphum padi resistant to organophosphate and carbamate insecticides. | apple grain aphid, rhopalosiphum padi (linnaeus), is an important wheat pest. in china, it has been reported that r. padi has developed high resistance to carbamate and organophosphate insecticides. previous work cloned from this aphid 2 different genes encoding acetylcholinesterase (ache), which is the target enzyme for carbamate and organophosphate insecticides, and its insensitive alteration has been proven to be an important mechanism for insecticide resistance in other insects. in this stud ... | 2007 | 17546082 |
| 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 |
| barley yellow dwarf virus: phenotypic mixing and vector specificity. | although the aphid rhopalosiphum padi does not regularly transmit the mav isolate of barley yellow drawf virus from singly infected oats, it often transmits mav, together with the serologically unrelated rpv isolate, from plants doubly infected by mav and rpv. vector specificity of the virus isolates appears to be a function of the virus capsid. some mav nucleic acid becomes coated with rpv capsid protein during simultaneous synthesis of the two isolates in the doubly infected plant. | 1970 | 17742616 |
| symbiont-mediated changes in lolium arundinaceum inducible defenses: evidence from changes in gene expression and leaf composition. | plants have multiple strategies to deal with herbivory, ranging from chemical or physical defenses to tolerating damage and allocating resources for regrowth. grasses usually tolerate herbivory, but for some cool-season grasses, their strategy may depend upon their interactions with intracellular symbionts. neotyphodium endophytes are common symbionts in pooid grasses, and, for some host species, they provide chemical defenses against both vertebrate and invertebrate herbivores. here, it was tes ... | 2007 | 17822401 |
| [effects of wheat leaf surface waxes on the feeding of two wheat aphid species]. | by using gc-ms and bioassay techniques, this paper studied the effects of different wheat varieties (cultivars) leaf surface waxes on the feeding of wheat aphids sitobion avenae and rhopalosiphum padi. the results showed that the leaf surface waxes of wheat varieties (cultivars) sn80, sn18 and zimail2 could stimulate the feeding of test aphids, while sn87 could not. gc-ms analysis showed that the chemical composition of leaf surface waxes differed with wheat varieties (cultivars). the main compo ... | 2007 | 17974245 |
| short-term population differences in the genetic architecture of life history traits related to sexuality in an aphid species. | one of the most important factors that determine the evolutionary trajectory of a suite of traits in a population is the structure of the genetic variance-covariance matrix (g). we studied the cyclically parthenogenetic aphid rhopalosiphum padi, whose populations exhibit two types of reproductive lineages respectively specialized in sexuality (that is, cyclically parthenogenetic lineages) and in asexuality (that is, obligate parthenogenetic lineages). we compared the quantitative genetics of lif ... | 2008 | 18212808 |
| bioactive triterpene derivatives from latex of two euphorbia species. | we have investigated the antifeedant and toxic effects of 23 semisynthetic terpenoid derivatives obtained through chemical modifications of the major components of euphorbia resinifera (alpha-euphol and alpha-euphorbol) and e. officinarum (obtusifoliol and 31-norlanostenol) latex on several insect species (spodoptera littoralis, myzus persicae and rhopalosiphum padi), their selective cytotoxicity on insect sf9 and mammalian cho cells and their phytotoxic effects on lactuca sativa. the conversion ... | 2008 | 18304594 |
| natural enemies act faster than endophytic fungi in population control of cereal aphids. | 1. fast-growing populations of phytophagous insects can be limited by the presence of natural enemies and by alkaloids that are produced by symbiotic associations of many temperate grass species with endophytic fungi. it is unclear if and how acquired plant defences derived from endophytic fungi interact with natural enemies to affect phytophagous insect populations. 2. to assess the relative importance of endophytic fungi compared to that of natural enemies on the population dynamics of phytoph ... | 2008 | 18312338 |
| host specialization in habitat specialists and generalists. | generalists and specialists use different cues to find their habitat and essential resources. while generalists have the advantage of exploiting a wider range of resources, they are predicted to be less efficient in using one particular resource compared to specialists. the level of specialization of parasitoids can be either at the habitat or at the host level; strategies used by either type are expected to differ. we examined interactions between three aphid parasitoid species that are a habit ... | 2008 | 18443827 |
| antifeedant activity of some polygodial derivatives. | polygodial (1) and its derivatives acetal 2 (propylene) and 3 (ethylene) were prepared and their antifeedant activity and toxic effects evaluated on several insect species with different feeding ecologies (spodoptera littoralis, leptinotarsa decemlineata, myzus persicae and rhopalosiphum padi) along with that of polygonone (4). we also tested their selective cytotoxic effects on insect-derived (spodoptera frugiperda ovarian sf9 cells) and mammalian chinese hamster ovary (cho) cells. the antifeed ... | 2008 | 18533465 |
| behavior of bird cherry-oat aphid and green peach aphid in relation to potato virus y transmission. | potato virus y is transmitted to potato in a nonpersistent manner by many aphid species, some of which do not colonize this crop. the behavior of bird cherry-oat aphid, rhopalosiphum padi (l.) on potato, solanum tuberosum l., a plant species that is not colonized by this aphid, was described and compared with that of the potato-colonizing green peach aphid, myzuspersicae (sulzer). a higher proportion of winged morph of r. padi than m. persicae left the plant, but aphids that stayed in contact wi ... | 2008 | 18613572 |
| cytopathological evidence for the division of barley yellow dwarf virus isolates into two subgroups. | the cytological survey of oat cells in tissue infected with different aphid-specific or aphid-nonspecific isolates of barley yellow dwarf virus (bydv) was concluded in this study with the examination of the alterations induced by schizaphis graminum-specific and s. graminum-nonspecific isolates. cytological alterations were similar with all four isolates examined, except that proliferated membranous inclusions, common with three of the isolates, were absent with s. graminum-nonspecific isolate 6 ... | 1979 | 18627893 |
| vascular cell alterations and predisposed xylem infection in oats by inoculation with paired barley yellow dwarf viruses. | electron microscope studies of tissue doubly infected with sitobion avenae-specific and rhopalosiphum padi-specific variants of barley yellow dwarf virus revealed four types of alteration patterns in infected phloem cells not previously observed in tissue infected with either isolate alone. cells with alteration patterns similar to those in tissue singly infected with either variant were also present. double infections with isolates mav (s. avenae-specific) and rpv (r. padi-specific) predisposed ... | 1981 | 18635099 |
| internal ribosome entry site of rhopalosiphum padi virus is functional in mammalian cells and has cryptic promoter activity in baculovirus-infected sf21 cells. | to substantiate the in vitro translational studies of a cross-kingdom, internal ribosome entry site (ires), the 5 untranslated region of the rhopalosiphum padi virus (rhpv), can function in mammalian cells and act as a shuttle ires between insect cells and mammalian cells. | 2008 | 18664329 |
| plum pox in north america: identification of aphid vectors and a potential role for fruit in virus spread. | abstract thirteen aphid species were tested for their ability to transmit pennsylvania isolates of plum pox virus (ppv) collected in columbia (penn-3), franklin (penn-4), and york (penn-7) counties, pa. four species, aphis fabae, a. spiraecola, brachycaudus persicae, and myzus persicae, consistently transmitted ppv in preliminary transmission tests. two species, metopolophium dirhodum and rhopalosiphum padi, were occasional inefficient vectors. toxoptera citricida, from florida, also was an effe ... | 2004 | 18943108 |
| variation in transmission efficiency among barley yellow dwarf virus-rmv isolates and clones of the normally inefficient aphid vector, rhopalosiphum padi. | the rmv strain of barley yellow dwarf virus (bydv-rmv) is an unassigned member of the luteoviridae that causes barley yellow dwarf in various cereal crops. the virus is most efficiently vectored by the aphid rhopalosiphum maidis, but can also be vectored with varying efficiency by r. padi and schizaphis graminum. field collections of alate aphids migrating into the emerging winter wheat crop in the fall of 1994 in central new york identified a high proportion of r. padi transmitting bydv-rmv. th ... | 2001 | 18944037 |
| aphid abundance on cereals in autumn predicts yield losses caused by barley yellow dwarf virus. | abstract barley yellow dwarf virus (bydv) damage to winter cereals and population dynamics of the aphid rhopalosiphum padi during fall were monitored in fields during 10 years at various locations in the northern half of france. logistic regression was used to examine whether a simple risk probability algorithm based only on the autumnal population dynamics of r. padi can accurately predict yield losses caused by bydv and, therefore, the need for insecticide treatment. results showed that the ar ... | 2003 | 18944319 |
| analyzing and modeling temporal disease progress of barley yellow dwarf virus serotypes in barley fields. | abstract population dynamics of padi avenae (pav), macrosiphum avenae (mav), and rhopalosiphum padi (rpv) virus serotypes of barley yellow dwarf virus (bydv) and of their main aphid vectors were studied in winter barley (hordeum vulgare) fields for three successive years in western france. an epidemiological model of the spread of viruses in the field was developed based on vector populations as forcing variables and the population dynamics of each virus serotype. this model accurately simulated ... | 2000 | 18944507 |
| [damage of rhopalosiphum padi (l.) (hemiptera: aphididae) on wheat plants related to duration time and density of infestation]. | aphids are considered relevant pests on wheat either by direct damage through sap sucking or by indirect damage vectoring bydv (barley yellow dwarf virus). rhopalosiphum padi l. has been observed infesting wheat fields with an increasing frequency. the knowledge and the available technology, besides being more related to other aphids species already recognized as pests, they are insufficient to control the specific problem of r. padi. thus, this work evaluated the effects of feeding duration and ... | 2008 | 19061045 |
| specific bottom-up effects of arbuscular mycorrhizal fungi across a plant-herbivore-parasitoid system. | the majority of plants are involved in symbioses with arbuscular mycorrhizal fungi (amf), and these associations are known to have a strong influence on the performance of both plants and insect herbivores. little is known about the impact of amf on complex trophic chains, although such effects are conceivable. in a greenhouse study we examined the effects of two amf species, glomus intraradices and g. mosseae on trophic interactions between the grass phleum pratense, the aphid rhopalosiphum pad ... | 2009 | 19219458 |
| multiple mechanisms responsible for differential susceptibilities of sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) to pirimicarb. | both sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) are the most important pests of wheat in china and usually coexist on the late period of wheat growth. pirimicarb was introduced into china for wheat aphid control in early 1990s, and differential susceptibilities of sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) to pirimicarb have been observed. a bioassay exhibited that rhopalosiphum padi possessed significantly higher susceptibility to pirimicarb than sitobion a ... | 2009 | 19413913 |
| rhopalosiphum padi (hemiptera: aphididae) responses to volatile cues from barley yellow dwarf virus-infected wheat. | in choice bioassays, rhopalosiphum padi l. nonviruliferous apterae preferentially locate near volatile organic compounds (vocs) emitted from barley yellow dwarf virus (bydv)-infected wheat plants compared with vocs from noninfected plants. however, the specific vocs responsible for r. padi responses are unknown. it is unclear also if r. padi responses to bydv-infected wheat are caused by arrestment or attraction. additionally, the responses of viruliferous apterae and nonviruliferous alate to by ... | 2009 | 19508794 |
| molecular analysis of capsid protein of homalodisca coagulata virus-1, a new leafhopper-infecting virus from the glassy-winged sharpshooter, homalodisca coagulata. | a new virus that infects and causes increased mortality in leafhoppers was isolated from the glassy-winged sharpshooter, homalodisca coagulata (say) (hemiptera: cicadellidae). the virus, named homalodisca coagulata virus -1, hocv-1, was associated with increased mortality of cultured 5(th) instar h. coagulata. to identify the presence of h. coagulata viral pathogens, cdna expression libraries were made from adult and nymphs. analysis using reverse transcriptase pcr demonstrated that the virus wa ... | 2006 | 19537993 |
| climate and agricultural context shape reproductive mode variation in an aphid crop pest. | in aphids, reproductive mode is generally assumed to be selected for by winter climate. sexual lineages produce frost-resistant eggs, conferring an advantage in regions with cold winters, while asexual lineages predominate in regions with mild winters. however, habitat and resource heterogeneities are known to exert a strong influence on sex maintenance and might modulate the effect of climate on aphid reproductive strategies. we carried out a hierarchical sampling in northern france to investig ... | 2009 | 19538348 |
| aphid fecundity and grassland invasion: invader life history is the key. | loss or gain of pathogens can determine the trajectory of biological invasions, and invasion by novel hosts also can alter pathogen dynamics to facilitate invasion. recent empirical and theoretical work has implicated infection by barley and cereal yellow dwarf viruses (b/cydv), a group of generalist pathogens of the poaceae family (grasses), as a necessary precursor to the invasion of over 9 million hectares of california's perennial grasslands by exotic annual grasses. the mechanism underlying ... | 2009 | 19688926 |
| endophyte-mediated resistance to herbivores depends on herbivore identity in the wild grass festuca subverticillata. | understanding factors that affect the context dependency of species interactions has been identified as a critical research area in ecology. the presence of symbionts in host plants can be an important factor influencing the outcome of plant-insect interactions. similarly, herbivore identity can alter the outcome of plant-symbiont interactions. symbiotic foliar fungal endophytes confer resistance to herbivores in economically important agronomic grasses, in part through the production of alkaloi ... | 2009 | 19689887 |
| biochemical markers of oxidative stress within tissues of cereal aphids. | effects of some dietary o-dihydroxyphenols on biochemical markers of oxidative stress within tissues of sitobion avenae (fabricius), (homoptera, aphididae) and rhopalosiphum padi (linnaeus), (homoptera, aphididae) has been studied. among the studied aphid morphs the highest concentration of total thiols, hydrogen peroxide and lipid peroxidation products (tbars) was noted for winged adults (alatae). higher content of h2o2 was observed within tissues of the oligophagous species r. padi while the m ... | 2009 | 19700385 |
| elevated co2 changes interspecific competition among three species of wheat aphids: sitobion avenae, rhopalosiphum padi, and schizaphis graminum. | effects of elevated co2 (twice ambient) on the interspecific competition among three species of wheat aphids (sitobion avenae, rhopalosiphum padi, and schizaphis graminum) and on wheat-aphid interactions were studied. wheat plants had higher biomass and yield and lower water and nitrogen content of grain when grown under elevated co2 than under ambient co2; levels of condensed tannins, total phenols, and total nonstructural carbohydrates were also higher in wheat ears under elevated co2. compare ... | 2009 | 19791595 |
| transcript profiles of two wheat lipid transfer protein-encoding genes are altered during attack by hessian fly larvae. | a sequence encoding a putative type-1 lipid transfer protein from wheat (triticum aestivum l. em thell) was identified through 'genecalling', an mrna profiling technology. the mrna for the hfr-ltp (hessian fly-responsive lipid transfer protein) gene decreased in abundance (196-fold) in susceptible wheat plants over the first eight days of attack by virulent hessian fly larvae (mayetiola destructor say). hfr-ltp encodes a putative protein containing eight cysteine residues that are conserved amon ... | 2010 | 19914842 |
| 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 |
| a novel wheat gene encoding a putative chitin-binding lectin is associated with resistance against hessian fly. | summary the gene-for-gene interaction triggering resistance of wheat against first-instar hessian fly larvae utilizes specialized defence response genes not previously identified in other interactions with pests or pathogens. we characterized the expression of hfr-3, a novel gene encoding a lectin-like protein with 68-70% identity to the wheat germ agglutinins. within each of the four predicted chitin-binding hevein domains, the hfr-3 translated protein sequence contained five conserved sacchari ... | 2007 | 20507479 |
| hfr-2, a wheat cytolytic toxin-like gene, is up-regulated by virulent hessian fly larval feedingdouble dagger. | summary both yield and grain-quality are dramatically decreased when susceptible wheat (triticum aestivum) plants are infested by hessian fly (mayetiola destructor) larvae. examination of the changes in wheat gene expression during infestation by virulent hessian fly larvae has identified the up-regulation of a gene, hessian fly responsive-2 (hfr-2), which contains regions similar to genes encoding seed-specific agglutinin proteins from amaranthus. hfr-2, however, did not accumulate in developin ... | 2005 | 20565667 |
| fungal endophytes of native grasses decrease insect herbivore preference and performance. | endophytic fungal symbionts of grasses are well known for their protective benefit of herbivory reduction. however, the majority of studies on endophyte-grass symbioses have been conducted on economically important, agricultural species-particularly tall fescue (lolium arundinaceum) and perennial ryegrass (lolium perenne)-raising the hypothesis that strong benefits are the product of artificial selection. we examined whether fungal endophytes found in natural populations of native grass species ... | 2010 | 20585809 |
| 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 |
| double subgenomic alphaviruses expressing multiple fluorescent proteins using a rhopalosiphum padi virus internal ribosome entry site element. | double subgenomic sindbis virus (dssinv) vectors are widely used for the expression of proteins, peptides, and rna sequences. these recombinant rna viruses permit high level expression of a heterologous sequence in a wide range of animals, tissues, and cells. however, the alphavirus genome structure and replication strategy is not readily amenable to the expression of more than one heterologous sequence. the rhopalosiphum padi virus (rhpv) genome contains two internal ribosome entry site (ires) ... | 2010 | 21085714 |
| the influence of virus-induced changes in plants on aphid vectors: insights from luteovirus pathosystems. | plant virus infection can alter the suitability of host plants for their aphid vectors. most reports indicate that virus-infected plants are superior hosts for vectors compared to virus-free plants with respect to vector growth rates, fecundity and longevity. some aphid vectors respond preferentially to virus-infected plants compared to virus-free ones, while others avoid infected plants that are inferior hosts. thus, it appears vectors can exploit changes in host plant quality associated with v ... | 2011 | 21549769 |
| within plant distribution of potato virus y in hairy nightshade (solanum sarrachoides): an inoculum source affecting pvy aphid transmission. | potato virus y (pvy) is vectored by several potato-colonizing and non-colonizing aphid species in a non-persistent manner and has a wide host range. it occurs naturally in several plant families. myzus persicae and macrosiphum euphorbiae are the most efficient potato-colonizing aphid vectors of pvy. rhopalosiphum padi, a cereal aphid that migrates in large numbers through potato fields during the middle of the growing season, does not colonize potato plants but can transmit pvy. hairy nightshade ... | 2011 | 21601597 |
| presence of a functional (ttagg)(n) telomere-telomerase system in aphids. | the structure of the telomeres of four aphid species (acyrthosiphon pisum, megoura viciae, myzus persicae and rhopalosiphum padi) was evaluated by southern blotting and fluorescent in situ hybridization, revealing that each chromosomal end consists of a (ttagg)(n) repeat. the presence of a telomerase coding gene has been verified successively in the a. pisum genome, revealing that aphid telomerase shares sequence identity ranging from 12% to 18% with invertebrate and vertebrate homologues, and p ... | 2011 | 21667174 |
| effect of acclimation on heat-escape temperatures of two aphid species: implications for estimating behavioral response of insects to climate warming. | an aphid usually stays at one feeding site for a long time to achieve its development and reproduction, while high temperatures can make it decide to escape from heat stress. climate warming increases daily high-temperature both in degree and time. however, it remains unknown whether such heat-escape behavior will be influenced by those daily temperature changes. in this study, a wheat-leaf temperature gradient was created based on field microhabitat temperatures. we defined a parameter, heat-es ... | 2011 | 21939662 |
| Assessing aphids potato virus Y-transmission efficiency: A new approach. | In order to develop an alternative method to optimize the relative efficiency factor (REF) assessment, the efficiency of transmission of Potato virus Y (PVY) by seven aphid species was examined. In vitro micropropagated potato plantlets were used to experiment on phenotypically and genetically homogeneous material. Species-specific acquisition access period (AAP) on a PVY-infected plantlet was assessed for each aphid species using electrical penetration graph (EPG) technique. Aphid probing behav ... | 2011 | 21884729 |
| detrimental and neutral effects of a wild grass-fungal endophyte symbiotum on insect preference and performance. | seed-borne epichloë/neotyphodium glenn, bacon, hanlin (ascomycota: hypocreales: clavicipitaceae) fungal endophytes in temperate grasses can provide protection against insect attack with the degree of host resistance related to the grass-endophyte symbiotum and the insect species involved in an interaction. few experimental studies with wild grass-endophyte symbiota, compared to endophyte-infected agricultural grasses, have tested for anti-insect benefits, let alone for resistance against more th ... | 2011 | 21867443 |
| species composition of aphid vectors (hemiptera: aphididae) of barley yellow dwarf virus and cereal yellow dwarf virus in alabama and western florida. | yellow dwarf is a major disease problem of wheat, triticum aestivum l., in alabama and is estimated to cause yield loss of 21-42 bu/acre. the disease is caused by a complex of viruses comprising several virus species, including barley yellow dwarf virus-pav and cereal yellow dwarf virus-rpv. several other strains have not yet been classified into a specific species. the viruses are transmitted exclusively by aphids (hemiptera:aphididae). between the 2005 and 2008 winter wheat seasons, aphids wer ... | 2011 | 21882679 |
| [effects of plant hedgerow on population dynamics of wheat aphid and its natural enemies]. | this paper studied the effects of planting different kinds of plant hedgerow (amorpha fruticosa, vetiveria zizanioides, eulaliopsis binata, and medicago sativa) on the population dynamics of wheat aphid and its natural enemies in the hillside wheat fields in ziyang city of sichuan province, southwest china. on the 20 degrees hillside, a. fruticosa hedgerow inhibited the occurrence of wheat aphid in the wheat field significantly, and the parasitoid densities were equal to or significantly lower t ... | 2011 | 22384596 |
| the impact of transgenic wheat expressing gna (snowdrop lectin) on the aphids sitobion avenae, schizaphis graminum, and rhopalosiphum padi. | this study investigated the impact of transgenic wheat expressing galanthus nivalis agglutinin (gna), commonly known as snowdrop lectin, on three wheat aphids: sitobion avenae (f.), schizaphis graminum (rondani), and rhopalosiphum padi (l.). we compared the feeding behavior and the life-table parameters of aphids reared on gna transgenic wheat (test group) and those aphids reared on untransformed wheat (control group). the results showed that the feeding behaviors of s. avenae and s. graminum on ... | 2011 | 22251654 |