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Diversité, caractéristiques évolutives et rôles des effecteurs salivaires du puceron du pois dans l’interaction avec ses plantes hôtes / Diversity, evolutionary characteristics and role of pea aphid salivary effectors in the interaction with host plantsBoulain, Hélène 15 December 2017 (has links)
Les effecteurs jouent un rôle fondamental lors des interactions antagonistes plantes-pathogènes en supprimant les défenses de la plante, permettant ainsi aux parasites de se développer. De tels effecteurs ont été caractérisés chez les insectes herbivores mais leur rôle dans la spécialisation à la plante reste méconnu. Les pucerons se nourrissent de la sève du phloème et injectent dans la plante des effecteurs salivaires. L'étude des patrons d’évolution des effecteurs, ainsi que la caractérisation de leurs fonctions sont nécessaires à la compréhension des mécanismes de spécialisation chez les pucerons. Au cours de ces travaux, nous avons cherché à identifier les effecteurs salivaires impliqués dans l'adaptation du puceron du pois, Acyrthosiphon pisum, à ses hôtes.Des approches évolutives, basées sur un nouveau catalogue de 740 effecteurs candidats surexprimés dans les glandes salivaires de A. pisum, ont révélé que certains d'entre eux évoluent rapidement et que l'expansion de familles multigéniques apparaît comme une source importante de diversité des effecteurs. En parallèle, ces travaux ont permis d'optimiser l'expression transitoire médiée par Agrobacterium dans le pois. Ce nouvel outil d'analyse fonctionnelle permet maintenant l'étude des effecteurs candidats afin d'identifier les effecteurs du puceron du pois impliqués dans l'adaptation à la plante hôte. / Effectors play fundamental roles in antagonistic plant-pathogen interactions mainly by suppressing plant defense and allow parasites to multiply on the plant. Some effectors have been characterized in herbivorous insects; however, their role to the evolution in plant specialization remains unknown. Aphids feed from phloem sap and inject salivary effectors into the host plant. Studying evolutionary patterns and characterizing functions of effectors appear as important steps toward unveiling the mechanisms of host plant specialization in aphids. This work sought to identify salivary effectors that are involved in plant specialization of the pea aphid, Acyrthosiphon pisum. Evolutionary approaches based on a new catalogue of 740 putative effectors that are up-regulated in salivary glands of A. pisum revealed that some of them evolve rapidly.Moreover, gene family expansion appear as an important source of novel effectors. In parallel, this work optimized Agrobacterium-mediated transient gene expression in pea to provide a new tool for functional analyses of pea aphid effectors. The construction of a comprehensive catalogue of A. pisum salivary effectors and evolutionary analysis of them provide new candidates in host plant adaptation. By using the gene expression tool now available in pea, functional characterization of candidates will help to identify the effectors that are involved in plant specialization of the pea aphid.
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Metabolic Engineering of Raffinose-Family Oligosaccharides in the Phloem Reveals Alterations in Patterns of Carbon Partitioning and Enhances Resistance to Green Peach AphidCao, Te 08 1900 (has links)
Phloem transport is along hydrostatic pressure gradients generated by differences in solute concentration between source and sink tissues. Numerous species accumulate raffinose-family oligosaccharides (RFOs) in the phloem of mature leaves to accentuate the pressure gradient between source and sinks. In this study, metabolic engineering was used to generate RFOs at the inception of the translocation stream of Arabidopsis thaliana, which transports predominantly sucrose. To do this, three genes, GALACTINOL SYNTHASE, RAFFINOSE SYNTHASE and STACHYOSE SYNTHASE, were expressed from promoters specific to the companion cells of minor veins. Two transgenic lines homozygous for all three genes (GRS63 and GRS47) were selected for further analysis. Sugars were extracted and quantified by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and 21-day old plants of both lines had levels of galactinol, raffinose, and stachyose approaching 50% of total soluble sugar. All three exotic sugars were also identified in phloem exudates from excised leaves of transgenic plants whereas levels were negligible in exudates from wild type leaves. Differences in starch accumulation or degradation between wild type and GRS63 and GRS47 lines were not observed. Similarly, there were no differences in vegetative growth between wild type and engineered plants, but engineered plants flowered earlier. Finally, since the sugar composition of the phloem translocation stream is altered in these plants, we tested for aphid feeding. When green peach aphids were given a choice between WT and transgenic plants, WT plants were preferred. When aphids were reared on only WT or only transgenic plants, aphid fecundity was reduced on the transgenic plants. When aphids were fed on artificial media with and without RFOs, aphid reproduction did not show differences, suggesting the aphid resistance is not a direct effect of the exotic sugars.
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Evaluation of introduced cowpea breeding lines for Aphid (Aphis Craccivora) and bruchid (Callosobruchus Rhodensiansus) resistance in South AfricaLetsoalo, Isaac Motsoeng January 2015 (has links)
Thesis (M.Sc. (Agricultural Agronomy)) --University of Limpopo, 2015 / Refer to document / Department of Agriculture Forestry and Fisheries (DAFF)
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Interactive effects of meloidogyne species and sugarcane aphid (melanaphis sacchari) on nematode resistance in sweet stem sorghum and effects of terpenoid-containing phytonematicides on both pestsMaleka, Koena Gideon January 2020 (has links)
Thesis (Ph.D. Agriculture (Plant Production)) -- University of Limpopo, 2020 / Worldwide, both root-knot (Meloidogyne species) and sugarcane aphid (Melanaphis
sacchari Zehntner), are economic pests on sugarcane and sorghum crops. In most
cases, each of the two pests is managed using host plant resistance due to the
economic benefits derived from this management strategy. The highly nematode
resistant sweet stem sorghum (Sorghum bicolor L.) cv. 'Ndendane-X1' used in ethanol
production, is highly sensitive to sugarcane aphid, with some indication that the latter
could interfere with nematode resistance in the sorghum cultivar. This study had four
objectives which collectively intended to investigate the interactive effects of infection
by three Meloidogyne species and infestation by aphid under different conditions on
resistance to nematode in a nematode-resistant sorghum cultivar. The research
objectives were achieved through four trials. In each trial a 2 × 2 factorial experiment,
each with and without nematode and aphid as first and second factors, respectively,
were conducted. Treatments were arranged in a randomised complete block design,
with six replications, and each experiment validated in time. At 150 days, after
emergence, the nematode × aphid interaction significantly reduced sucrose by 17, 74
and 42% in Meloidogyne enterolobii, Meloidogyne incognita and Meloidogyne javanica
trials, respectively. Aphid infestation of sorghum significantly increased the
reproductive potentials of the three respective Meloidogyne species by 196, 320 and
152%, but significantly, reduced plant growth variables from 20-44 and 48-51% in two
respective trials. The mineral nutrients S and Zn were reduced in leaf tissues of the
test cultivar in Trial 1, whereas Ca and Zn were respectively reduced by 24 and 51%
in Trial 2 and by 52 and 51% in Trial 3. Since the reproductive potential values for
Meloidogynqe species on the test sorghum cultivar were greater than unity and
nematode infection reduced the plant variables, cv. 'Ndendane-X1' lost resistance to xx
the test Meloidogyne species. In achieving Objective 2, procedures were similar to
those in Objective 1 except that the study was conducted under field conditions under
mixed nematode populations of M. enterolobii, M. incognita and M. javanica. Sorghum
seedlings were raised at 0.3 m × 0.3 m inter and intra row spacings. Soon after
emergence, plants were thinned to one per station, randomly selected for nematode
and nematode-aphid treatments. Mixed populations of Meloidogyne species (M.
enterolobii, M. incognita and M. javanica) at approximately 1:1:1 (v/v) ratio were
applied at 300 eggs + J2 per plants after thinning at the five plants which were used
as nematode alone treatments. The latter were also infested with 20 sugarcane aphids
to constitute a nematode + aphid treatments. Buffer zone plants separating the
treatments were monitored for aphids and stock borer, which were sprayed when
necessary. At 150 days after infestation, relative to nematode alone, nematode-aphid
significantly reduced degrees Brix from 13% to 61%, but significantly increased the
reproductive potential of mixed Meloidogyne species and root galls by 279 and 199%,
respectively. Also, the combined effect significantly reduced plant growth variables
from 35 to 55% and the mineral nutrient elements in leaf tissues of the cultivar from
33 to 73%. At 150 days after the treatment, the second and first order interaction
(Nemarioc-AL × Nemafric-BL × Mordica and Nemafric-BL × Mordica) had significantly
increased sucrose content from 48 to 66%, increased plant growth variables from 49
to 163%, increased accumulation of certain nutrient elements from 164 to 206%. The
terpenoid-containing phytonematicides could have potential future application in the
husbandry of ethanol-producing sweet stem sorghum cultivars in relation to increasing
sucrose above the 16% minimum for premium delivery fees and increased plant
growth. Under field conditions, in pest-free condition (Objective 3), drenched
terpenoid-containing phytonematicides significantly increased sucrose content at xxi
middle and bottom part of SSS cv. 'Ndendane-X1' by 66 and 48%. However, these
products did not significantly increase plant variables, except tiller number, which was
increased by 163 under first order interaction from Nemafric-BL and Mordica
phytonematicides. Similarly, nutrient elements variables had generally not been
increased by the interaction of these products, except Ca and K, which were increased
by 206 and 164%. In achieving Objective 4, a 2 × 2 × 2, with the first, second and third
factor being Nemarioc-AL (with and without), Nemafric-BL (with and without) and
Mordica (with and without) phytonematicides, respectively. on sorghum cultivar
infected with a mixture of Meloidogyne species and infested with aphids, under
microplot conditions, untreated control sucrose content remained below the standard
of 16 degrees Brix, whereas the second order interaction increased the variable far
above the standard, along with various plant growth variables also increased.
However, both nematode and aphid population densities were significantly reduced by
the interactions. Findings in this thesis constituted the first report where aphid
infestation broke resistance to Meloidogyne species in sweet stem sorghum cv.
'Ndendane-X1'. Therefore, the successful use of nematode resistance in the cultivar
in areas with high nematode population densities would depend upon the effective
management of the sugarcane aphid population densities. Also, the three terpenoid-containing phytonematicides would when combined or used alone have the potential future in the husbandry of sweet stem sorghum cultivars intended for ethanol
production and suppression of nematode population densities / National Research Foundation (NRF)
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Russian Wheat Aphid Survey in Southeastern Arizona, 1990Clark, Lee J. 09 1900 (has links)
Fifteen small grain fields, including eight wheat fields, two barley fields and five oat fields, throughout the grain growing areas of Graham, Greenlee and Cochise counties were surveyed weekly from the third week in March through the second week in June, to document the presence of Russian wheat aphid (RWA), other aphid, parasites and predators. RWA were found in all three counties and in all three grains. Presence of RWA caused chemical pest control applications in approximately 19%, 33% and 90% of the small grain fields in Graham, Greenlee and Cochise counties, respectively. Thirty three percent of the fields had beneficial parasites and predators were found 93% of the fields. Presence of parasites reduced the RWA populations in 80% of the cases and presence of predators had a dramatic effect on other aphids and was felt to be beneficial in controlling RWA.
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Arizona Russian Wheat Aphid Survey and Beneficial Release Report, 1990Clark, Lee J., Moore, Leon 09 1900 (has links)
During 1990 the emphasis on surveying was placed in the southeastern corner of the state, where damage was found to be most severe in previous years. Estimates of the incidence of and damage caused by the Russian Wheat Aphid (RWA) were made for the entire state. These estimates indicate that small grain producers in the state lost $212,000 due to this pest in 1990.
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A study of Myzus persicae (Sulzer) (Aphididae, Homoptera) with special reference to sweet potatoesKring, James Burton. January 1948 (has links)
Call number: LD2668 .T4 1948 K7 / Master of Science
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Development of sample collection methods and preliminary identifications of aphid salivary proteinsLamabadusuriya, Manuja R. January 1900 (has links)
Master of Science / Department of Chemistry / Christopher T. Culbertson / The study of aphid salivary secretome has practical importance on understanding interactions of aphids and their host plants. Around 250 species of aphids out of the identified 4000 aphid species are considered as serious pests. The experiments were performed with pea aphids (Acyrthosiphon pisum) that were feeding on bean plants (Vivia fabe). Pea aphids feed on plant phloem sap by probing their stylet into the sieve elements of the plant and secreting saliva for external digestion. In order to collect aphid salivary proteins from the secreted saliva, small scale and large scale sample collection methods were carried out. The small scale sample method was performed in microfluidic devices using 10-25 aphids. Aphids were able to feed on the artificial diet by probing through a stretched ParafilmTM and survived for 2-3 days in the microfluidic devices. The experiments proved that the aphid survival and feeding rate could be improved with the factors such as ventilation, light intensity and increasing diet volume. However it was difficult to collect sufficient amounts of aphid saliva for detection using small scale devices. The large scale sample collection method was performed by feeding 8000 aphids in large screened chamber for 24/48h. The collected salivary samples after undergone a concentration process was capable of collecting detectable aphid salivary secretions. The experimental conditions were adjusted to obtain optimized HPLC separations. Finally, LC/MS/MS followed by peptide sequence database searching were able to identify potential aphid salivary proteins.
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Biology of subterranean populations of woolly apple aphid, Eriosoma lanigerum (Hausmann)(Homoptera:Aphididae), in apple orchardsDamavandian, M. R. 03 1900 (has links)
Dissertation (PhD (Agric))--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: A study was made of the basic biology of subterranean Eriosoma
lanigerum (Hausmann) populations in apple orchards in the Western Cape
Province of South Africa.
The absence of cornicles and the presence of a vulva could be used to
identify 1st instar nymphs and adults respectively. Body length, body width and
length of the hind femur are useful for separating 2nd
, 3rd and 4th instars.
However, separation of 2nd from 3rd instar nymphs was very unreliable.
Maximum population growth rate was at 23°C while at 30 °C
population growth was zero. The estimated minimum and maximum threshold
temperatures for development were 4.32 and more than 30°C respectively.
Numbers of underground E. lanigerum in soil samples taken using
mechanical and hand augers were similar. However, numbers of aphids in
samples were influenced by the distance from the trunk at which the samples
were taken and the presence and the type of root material in the samples.
More aphids were recorded close to the trunk, and at a given distance from
the trunk more aphids were recorded if there was root material in the sample,
especially if the roots were galled. early autumn (February, March) and declined during winter, especially if the
winter rainfall was high. These cycles coincided with the nitrogen cycles in the
roots.
Embryos were also present in all instars throughout the year. There
were more embryos in the 4th instar and adult aphids than in the other instars.
The highest number of embryos in the 4th instar and adult aphids occurred
during spring, which coincided with peak nitrogen levels in the roots of apple
trees. Nitrogen levels in root material adjacent to galls and in ungalled roots
were higher than in root galls.
A number of entomopathogenic fungi, including species of
Conidiobolus, Hirsufella and Beauveria were found. Their present contribution
to biological control is not known.
A straw mulch suppressed subterranean E. lanigerum population levels
at least as well as the soil insecticide, imidacloprid, currently in use. / AFRIKAANSE OPSOMMING: 'n Studie van die basiese biologie van ondergrondse bevolkings van
, Eriosoma lanigerum (Hausmann) is in appelboorde in die Weskaap Provinsie
van Suid-Afrika uitgevoer.
Die afwesigheid van kornikels en die aanwesigheid van 'n vulva kon
gebruik word om die 1ste instar nimfe en volwassennes onderskeidelik te
identifiseer. Liggaamslengte, liggaamsbreedte en die lengte van die agterste
femur kon gebruik word om die 2de
, 3de en 4de instars van mekaar te
onderskei. Onderskeiding tussen 2de en 3de instar nimfe was egter baie
onbetroubaar.
Maksimum bevolkingsgroei het by 23°C plaasgevind, terwyl dit nul was
by 30 °C. Die beraamde minimum en maksimum temperature vir ontwikkeling
was by 4.32 en meer as 30°C onderskeidelik.
Getalle van ondergrondse E. lanigerum in grondmonsters wat geneem
is met gebruik van meganiese en hand bore was eenders. Getalle plantluise in
monsters is egter beïnvloed deur die afstand vanaf die stam waarby die
monsters geneem is en die teenwoordigheid van wortelmateriaal in die
monsters. Meer plantluise is aangeteken as daar wortelmateriaal in die
monsters was, en veral as daar galle op die wortels was. Die appelbloedluis was dwarsdeur die jaar ondergronds aktief.
Bevolkingsvlakke het gedurende die vroeë somer (November, Desember) en
vroeë herfs (Februarie, Maart) toegeneem, en gedurende die winter
afgeneem, veral as die winterreënval hoogwas.
Embrio's was ook teenwoordig dwarsdeur die jaar. Daar was meer
embrio's in die 4de instar en volwasse plantluise as in die ander instars. Die
hoogste aantal embrio's in die 4de instar en volwasse plantluise het in die lente
voorgekom, wat saamgeval het met piek stikstofvlakke in die wortels van
appelbome. Stikstofvlakke in wortelmateriaal aangrensend aan wortels en in
wortels sonder galle was hoër as in wortelgalle.
Talle entomopatogeniese swamme, insluitend spesies van
Conidiobolus, Hirsufella en Beauvaria IS gevind. Hulle huidige bydrae tot
biologiese beheer is nie bekend nie.
'n Strooideklaag het ondergrondse bevolkingsvlakke van E. lanigerum
tot ten minste dieselfde mate as die grondinsektedoder, imidacloprid, wat tans
in gebruik is, onderdruk.
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The Spotted Alfalfa Aphid in ArizonaTuttle, D. M., Barnes, O. L., Nielson, M. W., Roth, V. D., Schonhorst, M. H. 05 1900 (has links)
No description available.
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