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Protonectin (1-6): A novel chemotactic peptide from the venom of the social wasp Agelaia pallipes pallipes

BAPTISTA-SAIDEMBERG, Nicoli B.; SAIDEMBERG, Daniel M.; SOUZA, Bibiana M. de; CESAR-TOGNOLI, Lilian M. M.; FERREIRA, Virginia M. R.; MENDES, Maria Anita; CABRERA, Marcia P. dos Santos; RUGGIERO NETO, Joao; PALMA, Mario S.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
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Peptides constitute the largest group of Hymenoptera venom toxins; some of them interact with GPCR, being involved with the activation of different types of leukocytes, smooth muscle contraction and neurotoxicity. Most of these toxins vary from dodecapeptides to tetradecapeptides, amidated at their C-teminal amino acid residue. The venoms of social wasps can also contains some tetra-, penta-, hexa- and hepta-peptides, but just a few of them have been structurally and functionally characterized up to now. Protonectin (ILG-TILGLLKGL-NH(2)) is a polyfunctional peptide, presenting mast cell degranulation, release of lactate dehydrogenase (LDH) from mast cells, antibiosis against Gram-positive and Gram-negative bacteria and chemotaxis for polymorphonucleated leukocytes (PMNL), while Protonectin (1-6) (ILGTIL-NH(2)) only presents chemotaxis for PMNL However, the mixture of Protonectin (1-6) with Protonectin in the molar ratio of 1:1 seems to potentiate the biological activities dependent of the membrane perturbation caused by Protonectin, as observed in the increasing of the activities of mast cell degranulation, LDH releasing from mast cells, and antibiosis. Despite both peptides are able to induce PMNL chemotaxis, the mixture of them presents a reduced activity in comparison to the individual peptides. Apparently...

Avaliação de tipos de resistência de gramíneas forrageiras à cigarrinha das-raízes Mahanarva fimbriolata (Stål, 1854) (Hemiptera: Cercopidae); Evaluation of types of resistance of grasses to the spittlebug Mahanarva fimbriolata (Stål, 1854) (Hemiptera: Cercopidae)

Grisoto, Eliane
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/04/2013 PT
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Os objetivos deste trabalho foram selecionar gramíneas forrageiras com potencial de resistência a Mahanarva fimbriolata, bem como determinar tipos de resistência presentes, por meio da avaliação do efeito sobre a biologia do inseto e de testes de tolerância. Nas gramíneas mais promissoras foi também aplicado o fungo Metarhizium anisopliae (Metsch.) Sorokin para avaliar um possível efeito associado deste com a resistência vegetal. Os ensaios foram realizados sem chance de escolha, com insetos provenientes de criação estoque. No ensaio de biologia, realizado em laboratório com 12 genótipos, os seguintes parâmetros foram avaliados: mortalidade e duração da fase ninfal; peso e longevidade dos adultos; período de pré-oviposição e número de ovos/fêmea; e viabilidade e a duração do período embrionário. No ensaio de tolerância realizado com três gramíneas, em casa de vegetação, foram utilizadas duas densidades de cigarrinhas (dois e quatro casais), avaliando-se o dano causado (com base em escala de notas) aos 3º e 7º dias após a infestação e o crescimento e rebrote das gramíneas ao 14º dia após a desinfestação. Para verificar a associação de plantas resistentes com o fungo M. anisopliae, foram utilizadas...

Parâmetros biológicos de Bemisia Tabaci (genn.) biótipo B (hemiptera: aleyrodidae) em genótipos de algodoeiro

Campos, Zeneide Ribeiro; Boiça Júnior, Arlindo Leal; Lourenção, André Luiz; Campos, Alcebiades Ribeiro
Fonte: Instituto Agronômico de Campinas Publicador: Instituto Agronômico de Campinas
Tipo: Artigo de Revista Científica Formato: 1003-1007
POR
Relevância na Pesquisa
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A mosca-branca Bemisia tabaci biótipo B é uma praga de grande importância econômica para muitas culturas em todo o mundo. No Brasil, especialmente no Estado da Bahia, essa praga causou perdas que variam entre 30% e 70% em cultura de algodão. Essa pesquisa foi desenvolvida com o objetivo de avaliar parâmetros biológicos de B. tabaci biótipo B em genótipos de algodoeiro para verificar a possível ocorrência de antibiose como mecanismo de resistência sob condições de casa de vegetação. Os genótipos estudados foram IAC-23, Coodetec 406, BRS Aroeira, Fabrika, Coodetec 407, IAC-24, Makina, IAC 20-233, Coodetec 401 e CNPA Acala I. Foram avaliados os períodos de incubação e ninfal, o desenvolvimento total e a longevidade. Dos genótipos avaliados observou-se em Coodetec 406 maior período ninfal (14,7 dias) e IAC-23 a menor viabilidade de ninfas (30,7%), indicando a ocorrência de resistência do tipo antibiose contra essa mosca-branca.; The silverleaf whitefly Bemisia tabaci B biotype is an important pest of many crops throughout the world. In Brazil, specifically in the Bahia State, this insect caused losses estimated to 30-70% on cotton crops. The purpose of this research was to investigate biological parameters of the silverleaf whitefly biotype B in genotype of cotton bush to verify a possible occurrence of antibiosis as resistance mechanism cotton...

Desenvolvimento de Holhymenia histrio (Fabr.) (Hemiptera: Coreidae) em frutos de cinco genótipos de maracujazeiro (Passiflora spp.)

Baldin, Edson Luiz Lopes; Boiça Jr., Arlindo L.
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica Formato: 421-427
POR
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Visando observar a antibiose de frutos de diferentes genótipos de maracujazeiro (Passiflora spp.) frente ao percevejo Holhymenia histrio (Fabr.), realizaram-se ensaios na Faculdade de Ciências Agrárias e Veterinárias/UNESP, Jaboticabal, SP. Foram acompanhadas diariamente ninfas recém-eclodidas em frutos de diferentes genótipos, avaliando-se a duração e a mortalidade de cada ínstar ninfal; o peso das ninfas de quarto ínstar; o peso de adultos e a fecundidade. Os frutos dos genótipos P. giberti, P. coccinea, P. alata e P. edulis f. flavicarpa apresentaram efeitos antibióticos sobre o percevejo H. histrio, com destaque para o primeiro deles, onde ocorreram altas mortalidades, sobretudo no segundo ínstar ninfal, indicando ser o menos adequado. Os frutos de P. nitida apresentaram-se como os mais adequados para o desenvolvimento das ninfas e adultos do percevejo.; Antibiosis was observed in fruits of different passion fruit genotypes (Passiflora spp.) on Holhymenia histrio Fabr. Essays were accomplished in the Department of Entomology and Nematology UNESP, Jaboticabal, SP. The development of newly-hatched nymphs on fruits of the different genotypes was studied. The duration and mortality of each nymphal instar...

Characterization of antibiosis and antixenosis to the whitefly silverleaf Bemisia tabaci B biotype (Hemiptera: Aleyrodidae) in several squash varieties

Baldin, Edson Luiz Lopes; Beneduzzi, Ronaldo Antonio
Fonte: Springer Heidelberg Publicador: Springer Heidelberg
Tipo: Artigo de Revista Científica Formato: 221-227
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); The objective of this study was to investigate the potential resistance mechanisms to Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B biotype, in eight Cucurbita pepo varieties. Attractivity, oviposition preference, and nymphal development were evaluated under greenhouse and laboratory conditions. Variety Bianca was the least attractive to adult whiteflies in multi-choice tests. The whiteflies showed oviposition nonpreference (antixenosis) for Novita Plus, Bianca and Sandy in multi-choice test, and similar results were observed in no-choice tests with varieties Bianca, Novita, Caserta Cac and Sandy. Sandy expressed high antibiosis levels against whitefly nymphs, leading to 63.9% mortality. The high level of resistance in variety Sandy can serve as base for genetic improvement of C. pepo focusing on the development of resistant varieties to B. tabaci B biotype.

Resistência de genótipos de tomateiro ao ataque de Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae)

Bottega, Daline Benites
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: vi, 48 f. : il.
POR
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV; Objetivou-se com este trabalho avaliar possíveis fontes de resistência de genótipos de tomateiro a Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), dos tipos não preferência, para oviposição, alimentação e antibiose, em avaliações de parâmetros biológicos das fases jovem e adulta do inseto. Os experimentos foram realizados no Laboratório de Resistência de Plantas a Insetos, do Departamento de Fitossanidade da Faculdade de Ciências Agrárias e Veterinárias, Câmpus de Jaboticabal-SP. As espécies de tomateiro utilizadas foram Lycopersicon esculentum (Mill.) (cv. Santa Clara, cinco híbridos: Saladete Italiano Ty Tyna, Santa Cruz Débora Ty, Salada Lumi, Saladete Italiano Andrea Victory e Santa Cruz Ty Carina Ty), Lycopersicon hirsutum f. glabratum (C.H. Mull.) (linhagens PI 134418 e PI 134417) e Lycopersicon pimpinellifolium (Just) (linhagens NAV 1062 e PI 126931), para os testes de não preferência para oviposição e alimentação, e todos esses materiais, menos Santa Cruz Ty Carina Ty, para o teste de antibiose. Para os testes de não preferência para oviposição...

Resistência de genótipos de amendoim (Arachis hypogaea L.) de hábitos de crescimento ereto e rasteiro a Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Noctuidae)

Pitta, Rafael Major
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: vi, 55 f. : il.
POR
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV; Objetivou-se com este trabalho avaliar possíveis fontes de resistência de genótipos de amendoinzeiro a Anticarsia gemmatalis Hübner, 1818 dos tipos não-preferência para alimentação, oviposição e antibiose, em avaliações de parâmetros biológicos das fases jovem e adulta do inseto, tendo como objetivo secundário demonstrar a viabilidade do emprego de análises multivariadas para interpretação de dados em testes de antibiose. Os experimentos foram realizados sob condições controladas (temperatura: 26 ± 2ºC, U.R. 60 ± 10% e fotofase de 12 horas) no Laboratório de Resistência de Plantas a Insetos, pertencente ao Departamento de Fitossanidade da Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal/SP. Os genótipos utilizados foram: IAC 5; IAC 8112; IAC 22 e IAC Tatu st de hábito de crescimento ereto, e IAC 147; IAC 125; IAC Caiapó e IAC Runner 886 de hábito crescimento rasteiro. Os testes de não-preferência para alimentação foram realizados com e sem chance de escolha, utilizando lagartas de 3º ínstar. As avaliações foram realizadas aos 3; 5; 10; 15; 30; 60; 120; 360 e 480 minutos após a liberação...

Characterization of antibiosis to the redbanded stink bug Piezodorus guildinii (Hemiptera: Pentatomidae) in soybean entries

Silva, Jose P. G. F.; Baldin, Edson L. L.; Souza, Efrain S.; Canassa, Vinicius F.; Lourencao, Andre L.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 649-657
ENG
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Stink bugs are among the major pests of soybean [Glycine max (L.) Merrill] worldwide. Piezodorus guildinii [Westwood] (Hemiptera: Pentatomidae) is one of the predominant pest species, causing more severe damage in many regions than other stink bugs. Its attack reduces yield and quality of the beans. Plant resistance is a valuable strategy in integrated pest management that can reduce insect populations below economic injury level. Here, we report the resistance of 17 soybean entries to P. guildinii. PI 229358, PI 274454, L1-1-01, IAC 19, PI 171451, PI 227687, IAC 100, IAC 78-2318, PI 274453, and IAC 74-2832 caused high nymphal mortality (greater than 90 %), indicating the expression of antibiosis. IAC 100, IAC 74-2832, PI 274453, and IAC 24 also increased the length of the nymphal stage of P. guildinii, showing the same mechanism of resistance. Our findings may be useful for breeding programs that focus on the resistance of soybeans to insects.

Characterization of antibiosis to the silverleaf whitefly Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) in cowpea entries

Cruz, Patricia Leite; Baldin, Edson Luiz Lopes; Castro, Maria de Jesus Passos de
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 639-645
ENG
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The silverleaf whitefly, Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae), is considered one of the most important pests of cowpea (Vigna unguiculata L. Walp.), limiting the productivity of this crop worldwide. Chemical control is still the main strategy for the management of populations of this insect. However, due to the harmful effects of pesticides on the environment and to humans, less injurious alternatives have been investigated. Along this line, the use of resistant genotypes can be a valuable tool for the control of the silverleaf whitefly. In this paper, we investigate some biological aspects of B. tabaci biotype B confined on 14 genotypes of cowpea. We evaluated the incubation period, egg viability, duration of nymphal stages, total duration of the juvenile phase, instar mortality and total mortality of the immature stage. The genotype MNC 99-541 F21 exhibited antibiosis against the whitefly, prolonging the lifecycle of the insect. The genotypes Canapu, BRS-Urubuquara and TE97-304 G-4 also exhibited antibiosis, causing high nymphal mortality. These results may help in breeding programmes to develop cowpea lines with resistance to B. tabaci biotype B.

Genetic mechanisms underlying apimaysin and maysin synthesis and corn earworm antibiosis in maize (Zea mays L.).

Lee, E A; Byrne, P F; McMullen, M D; Snook, M E; Wiseman, B R; Widstrom, N W; Coe, E H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1998 EN
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C-glycosyl flavones in maize silks confer resistance (i.e., antibiosis) to corn earworm (Helicoverpa zea [Boddie]) larvae and are distinguished by their B-ring substitutions, with maysin and apimaysin being the di- and monohydroxy B-ring forms, respectively. Herein, we examine the genetic mechanisms underlying the synthesis of maysin and apimaysin and the corresponding effects on corn earworm larval growth. Using an F2 population, we found a quantitative trait locus (QTL), rem1, which accounted for 55.3% of the phenotypic variance for maysin, and a QTL, pr1, which explained 64.7% of the phenotypic variance for apimaysin. The maysin QTL did not affect apimaysin synthesis, and the apimaysin QTL did not affect maysin synthesis, suggesting that the synthesis of these closely related compounds occurs independently. The two QTLs, rem1 and pr1, were involved in a significant epistatic interaction for total flavones, suggesting that a ceiling exists governing the total possible amount of C-glycosyl flavone. The maysin and apimaysin QTLs were significant QTLs for corn earworm antibiosis, accounting for 14. 1% (rem1) and 14.7% (pr1) of the phenotypic variation. An additional QTL, represented by umc85 on the short arm of chromosome 6, affected antibiosis (R2 = 15.2%)...

Antibiosis to the Southern Chinch Bug by St. Augustinegrass Accessions

Reinert, James A.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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Twenty-six accessions of St. Augustinegrass, Stenotaphrum secundalum (Walt.) Kuntze, were evaluated under laboratory conditions for resistance to Blissus insularis Barber. ‘Floratam’, FA-46, 64, 73, 80, 87, 121, 131, 145, 217, and 243 when compared to common St. Augustinegrass exhibited significant antibiosis (P<0.05) to the caged adult southern chinch bug populations within 4–7 days. Floratam produced significantly more antibiosis (P<0.05) than any other selection when evaluated at 4 and 5 days but by the 7-day evaluation FA-46, 73, 87, 121, and 131 were not significantly different from Floratam. Significant (P<0.05) antibiosis to the 5th instars also was shown for 8 of the accessions including Floratam. A similar difference was also shown in the percentage of confined nymphs which survived but failed to molt to adults within 7 days for Floratam and FA-46, 131, and 173. Unlike Floratam which is very coarse-textured, the resistant selections FA-80, 121, 131, 145, and 243 are fine-textured. Like Floratam all 5 of these are relatively fast-growing, although FA-243 is the most vigorous accession.

St. Augustinegrass Antibiosis to Southern Chinch Bug (Hemiptera: Lygaeidae) and to St. Augustine Decline Strain of Panicum Mosaic Virus

Crocker, Robert L.; Toler, Robert W.; Beard, James B.; Engelke, M. C.; Kubica-Breier, Janina S.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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Antibiosis to Texas populations of southern chinch bug, Blissus insularis Barber, was tested in 38 selected cultivars and experimental lines of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze. High levels of resistance were measured in the experimental lines PI-410357, New Zealand-2, Mutant-5, TXSA-8202 (=Mutant-6), TXSA- 8218 (=Mutant-8), and the cultivar ’Floralawn.’ Although some B. insularis in Florida reportedly have overcome resistance by ’Floratam,’ we encountered no evidence of such a phenomenon. FA-243 was susceptible and FA-82 was slower acting than ‘Floratam.’ Both lines have been reported to be highly resistant to Florida B. insularis. Experimental lines DALSA-8208, DALSA-8216, and DALSA-8401 demonstrated moderate levels of antibiosis. The cultivars ‘Raleigh’ and ‘Seville’ and several experimental lines were susceptible. Bioassays of the grasses for resistance to the St. Augustine decline strain of the Panicum mosaic virus (PMV-SAD) indicated that all were resistant to the virus except FA-82, ‘Texas Common,’ TXSA-8262, DALSA-8203, DALSA-8207, DALSA-8209, DALSA-8210, DALSA-8212, DALSA-8217, DALSA-8403, and WT-1.

Antibiosis Effects of Wild Dry Bean Accessions on the Mexican Bean Weevil and the Bean Weevil (Coleoptera: Bruchidae)

Cardona, Cesar; Posso, Carmen E.; Kornegay, Julia; Valor, Jose; Serrano, Miguel
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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High levels of antibiosis resistance to the Mexican bean weevil (MBW), Zabrotes subfasciatus (Boheman), and the bean weevil (BW), Acanthoscelides obtectus (Say), in wild dry bean, Phaseolus vulgaris L., accessions were caused primarily by high mortality of late first instars and, to a lesser extent, by high mortality of early second instars, coupled with a significant prolongation of the duration of the first instar. Antibiosis had a significant effect on the fecundity of F, females reared on resistant varieties. Seed integument did not appear to act as a barrier for larvae of the bean weevil. Rearing of both insects on “artificial” seeds further demonstrated that factors responsible for resistance are present in the cotyledons.

Conditioning Host Plant Affects Antixenosis and Antibiosis to Russian Wheat Aphid (Homoptera: Aphididae)

Robinson, J.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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The effects of conditioning host on antixenosis and antibiosis of test hosts to Diuraphis noxia (Mordvilko) were studied. Three methods of measuring antixenosis were compared and found to be approximately equally effective. Apterous D. noxia reared on a resistant barley, Hordeum vulgare L., showed no preference between four barleys; but oats, Avena sativa L., were less preferred. D. noxia reared on wheat, Triticum aestivum L., generally showed no preference between four barleys and wheat. There was no difference between two clones of D. noxia in the antixenosis and antibiosis of two barleys (one resistant and the other susceptible to D. noxia), wheat, and oats. Conditioning host influenced antixenosis as evidenced by a significant interaction between the effects of conditioning host and test host. D. noxia conditioned on the barleys and wheat showed no preference for these genotypes, but oats were less preferred. D. noxia conditioned on oats showed an increased preference for oats relative to the two barleys and wheat compared with aphids conditioned on the two barleys and wheat. Conditioning host influenced antibiosis as evidenced by a significant interaction between the effects of conditioning host and test host. D. noxia conditioned on one of the barleys contained more embryos than expected when tested on oats. However...

Comparison of Silk Maysin, Antibiosis to Corn Earworm Larvae (Lepidoptera: Noctuidae), and Silk Browning in Crosses of Dent x Sweet Corn

Guo, B. Z.; Widstrom, N. W.; Wiseman, B. R.; Snook, M. E.; Lynch, R. E.; Plaisted, D.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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Sweet corn is one of the highest ranking vegetable crops in the United States in terms of both market value and total acreage; it also ranks among the top vegetable crops in terms of pesticide usage. Ear damage caused by insects is the most significant concern to producers. An estimated 25–40 insecticide applications may be made in a single season to control ear-feeding insects. Plant resistance is an alternative strategy to alleviate environmental concern when pesticides are used. In this study we investigated the feasibility of transferring antibiosis to corn earworm, Helicoverpa zea (Boddie), from dent corn with high silk maysin to sweet corn. Relationships among silk maysin concentration, antibiosis to corn earworm, and silk browning in their F2 segregating populations were determined. Lyophilized high maysin silks bioassays produced low larval weights, thus providing evidence that damage to sweet corn by corn earworm could be reduced by increasing silk maysin concentration. Simple correlation coefficients indicated a highly significant negative association between silk maysin concentrations and 8-d corn earworm larval weights (r ≈ −0.80, P < 0.0001). Silk browning was also closely associated with silk maysin concentrations and antibiosis. Diets containing mid-dark silks reduced larval weights by 68% compared with larval weights (588 mg) on the bean diet control. Maysin analyses and dry-silk bioassays also revealed that if maysin is present in F2 plants from sweet corn kernels...

Feeding Behavior of Russian Wheat Aphid (Hemiptera: Aphididae) Biotype 2 in Response to Wheat Genotypes Exhibiting Antibiosis and Tolerance Resistance

Lazzari, Sonia; Starkey, Sharon; Reese, John; Ray-Chandler, Andrea; McCubrey, Raymond; Michael Smith, C.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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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 chlorosis and leaf rolling, and all test genotypes expressed some degree of chlorosis and leaf rolling, except Dn7, which was not damaged. Both Dn7 and Dnx expressed antibiosis effects, significantly reducing the numbers of aphids on plants and the intrinsic rate of aphid increase. Dn6 plants seemed to contain tolerance, exhibiting tolerance index measurements for leaf and root dry weight and plant height that were significantly lower than those of the susceptible Dn0 plants. Principal component analyses indicated that antibiosis and leaf rolling data explained 80% of the variance among genotypes. Electronic penetration graph analysis demonstrated contrasting results between RWA1 and RWA2 phloem sieve element phase feeding events...

Wheat Antixenosis, Antibiosis, and Tolerance to Infestation by Delphacodes kuscheli (Hemiptera: Delphacidae), a Vector of "Mal de Rio Cuarto" in Argentina

Brentassi, M. E.; Corrales, C.; Snape, J. W.; Dixon, A.F.G.; Castro, A. M.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
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“Mal de Río Cuarto,” is the most important virus disease of corn, Zea mays L., in Argentina. It is caused by the Mal de Río Cuarto virus (family Reoviridae, genus Fijivirus. MRCV), which is a persistent virus transmitted by Delphacodes kuscheli (Fennah 1955) (Hemiptera: Delphacidae). Because corn is not a natural host of D. kuscheli, it has little protection from this pest. In contrast, wheat, Triticum aestivum L., is one of the main hosts of this vector and a reservoir of MRCV. The aim of this work was to identify genes involved in antixenosis, antibiosis, and tolerance of infestation by D. kuscheli in wheat, which might be used to reduce the population level of this vector on corn. A set of recombinant dihaploid (RDH) lines for chromosome 6A derived from the F1 cross between ‘Chinese Spring’ (CS) × ‘Chinese Spring (Synthetic 6A)’ (S6A) substitution line, was used for mapping. The S6A parental line is resistant to the MRCV vector. Antixenosis, antibiosis, and tolerance were evaluated using conventional tests in controlled environmental conditions. Most of the RDH and S6A showed higher levels of antixenosis against D. kuscheli than the parental line CS. The RDH lines showed highly significant antibiosis in terms of the duration of first...

Does anaerobic bacterial antibiosis decrease fungal diversity in oral necrobacillosis disease?

Antiabong, J.; Boardman, W.; Adetutu, E.; Brown, M.; Ball, A.
Fonte: W B Saunders Co Ltd Publicador: W B Saunders Co Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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Oral necrobacillosis (ON) is a model polymicrobial disease that affects macropods in captivity and livestock. Several studies in humans and animals have focused mainly on the bacterial etiology of this disease with little or no information on the role/association of fungi with ON. Using a Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) assay and statistical analysis of the fungal community structure in healthy and disease groups, a reduction in the species diversity and drastic reduction (>1000 fold) in the fungal population in wallabies with ON was observed. Furthermore, an in vitro assay revealed a potential anaerobic-bacteria antibiosis mechanism in the observed decrease in fungal population in ON and a synergistic bacterial-fungal interaction in wallabies with healthy oral status. This study contributes to our knowledge of the fungal community structure associated with ON and forms the basis for an investigation at an epidemiological scale in order to exploit the clinical potentials of these findings.; John F. Antiabong, Wayne Boardman, Eric M. Adetutu, Melissa H. Brown, Andrew S. Ball

Evaluation of a choice-test method to assess resistance of melon to Aphis gossypii Glover (Homoptera: Aphididae) by comparison with conventional antibiosis and antixenosis trials

Martín, B.; Fereres, Alberto
Fonte: Japanese Society of Applied Entomology and Zoology Publicador: Japanese Society of Applied Entomology and Zoology
Tipo: Artículo Formato: 82094 bytes; application/pdf
ENG
Relevância na Pesquisa
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The Vat gene of melon confers resistance to Aphis gossypii through both antixenotic and antibiotic mechanisms. This article reports several experiments carried out to detect this gene in melon lines from a melon breeding program. These included antixenosis, antibiosis and virus transmission trials. Results showed that, for Vat detection, antibiosis trials were not as discriminating as antixenosis trials. The antixenosis trials discriminated more clearly between resistant and susceptible lines after 72 h than after 24 h. We additionally developed a rapid and simple choice-test method to assess antixenotic effect. This test discriminated rapidly and effectively between resistant and susceptible lines. The aphids showed significant rejection of resistant lines after only 1.5 h of exposure. Thus compared to the conventional antixenosis trials this test has several advantages, including rapidity, ease of use, and non-destructiveness (allowing replicate testing of a single plant, or subsequent obtention of seed).; Peer reviewed

Mechanisms of Oryza sativa (Poaceae) resistance to Tagosodes orizicolus (Homoptera: Delphacidae) under greenhouse condition in Venezuela

González,Alex; Labrín,Natalia; Álvarez,Rosa M.; Jayaro,Yorman; Gamboa,Carlos; Reyes,Edicta; Barrientos,Venancio
Fonte: Revista de Biología Tropical Publicador: Revista de Biología Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2012 EN
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Tagosodes orizicolus is one of the main plagues of rice in tropical America causing two types of damages, the direct one, feeding and oviposition effect, and an indirect one, by the transmission of the “Rice hoja blanca virus”. During 2006-2007 we carried out research under greenhouse conditions at Fundación Danac, Venezuela, in order to determine the mechanisms of antixenosis, antibiosis and tolerance to T. orizicolus, which could be acting in commercial varieties and advanced lines of the rice genetic breeding programs of INIA and Fundación Danac. The method of free feeding was used for the antixenosis evaluation, whereas the method of forced feeding was used for antibiosis evaluation (effect on survival and oviposition). Additionally, we used the indirect method based on biomass depression to estimate the tolerance. Some of the evaluated traits included: grade of damage, number of insects settling on rice plants, percentage of sogata mortality at the mature state, number of eggs in the leaf midrib and an index of tolerance. The results showed that rice genotypes possess different combinations of resistance mechanisms, as well as different grades of reactions. The susceptible control ‘Bluebonnet 50’ was consistently susceptible across experiments and the resistant control ‘Makalioka’ had high antixenosis and high antibiosis based on survival and oviposition. The rest of the genotypes presented lower or higher degrees of antixenosis and antibiosis for survival and viposition. The genotype ‘FD0241-M-17-6-1-1-1-1’ was identified with possible tolerance to the direct damage of sogata.