The green peach aphid (GPA; Myzus persicae Sülzer) is a damaging pest that has a broad host range that includes plants in the Brassicaceae, Solanaceae, Cucurbitaceae, and Rosaceae families. It also vectors several important viral diseases. However, how plants perceive GPA to limit infestation is poorly understood. This study demonstrates an important role for the HOMOLOG OF RPW8 4 (HR4), which encodes a protein that contains the RESISTANCE TO POWDERY MILDEW 8 (RPW8) motif that is found in some intracellular receptor proteins that are involved in defense against pathogens. In the accession Moscow of Arabidopsis thaliana, a Brassicaceae family plant, located at the RPW8 locus on chromosome 3 are RPW8.1 and RPW8.2, which confer resistance against a broad spectrum of powdery mildew pathogens. In comparison, in the powdery mildew-susceptible accession Columbia (Col-0), RPW8.1 and RPW8.2 are replaced by the homologous HR4Col-0. HR4Col-0, but not its homologs, was found to be involved in limiting GPA infestation. The presence of HR4Col-0 adversely impacted GPA fecundity, feeding from the phloem, and host selection. Transcriptomic analysis revealed that HR4Col-0 influences biological processes such as response to chitin, amino acid metabolism, and lipid metabolism. The resistance-enhancement ability of HR4Col-0 towards GPA infestation could be transferred to the Arabidopsis accession Wassilewskija and the oil-seed crop Camelina sativa, both of which naturally lack HR4. These findings position HR4Col-0 as a promising candidate for enhancing resistance to the GPA in plants other than Arabidopsis. This research significantly advances our understanding of plant immune mechanisms against an important agricultural pest.

Orientador: Arlindo Leal Boiça Júnior / Banca: Francisco Jorge Cividanes / Banca: José Djair Vendramim / Resumo: 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, contando o número de indivíduos se alimentando por genótipo, e quantificando ao término do experimento a área foliar consumida por genótipo. Para os testes de não-preferência para oviposição, avaliou-se o número de ovos por cm2 de folha. Os genótipos IAC Caiapó, IAC Runner 886, IAC 125, IAC 5 e IAC 147 apresentaram características de resistência por serem menos preferidos para alimentação de A. gemmatalis, sendo IAC 147 menos preferido nos testes de não-preferência para alimentação com e sem chance de escolha, e não-preferência para oviposição sem chance de escolha. No teste de antibiose além dos genótipos de amendoim, utilizouse o genótipo de soja BR 16, como padrão de suscetibilidade...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aimed to evaluate possible resistance sources of peanuts genotypes for no feeding preference, no oviposition preference and antibiosis tests, in evaluations of biological parameters of adult and larvae phases of Anticarsia gemmatalis, and as secondary objective to confirm the importance of multivariate statistical for interpretation of data in antibiosis tests. Experiments were realized under controlled conditions (temperature: 26 ± 2ºC, R.H. 60 ± 10% and photophase of 12 hours) in the Laboratory of Plant Resistance to Insects, pertaining to Department of Fitossanidade - Faculdade de Ciências Agrárias e Veterinárias, Campus de Jaboticabal/SP. The genotypes used were: IAC 5; IAC 8112; IAC 22 and IAC Tatu st of upright growth habit, and IAC 147; IAC 125; IAC Caiapó and IAC Runner 886 of runner growth habit. In the no-preference feeding tests, larvae's of 3º ínstar were utilized, being the evaluations done to: 3; 5; 10; 15; 30; 60; 120; 360 and 480 minutes after liberation, counting the numbers of individuals feeding per genotype and quantifying in experiment finish the leaf area consumed per genotype. For the no-preference oviposition tests, the number of eggs per cm2 of leaf were evaluated. The genotypes IAC Caiapó, IAC Runner 886, IAC 125, IAC 5 e IAC 147 demonstrated resistance characteristics, presenting low preference to feeding of A. gemmatalis, especially IAC 147 that presented low preference in choice and no choice feeding tests, and no choice oviposition test. For the antibiosis test, beyond the peanuts genotypes the soybean genotype BR 16 was included as susceptibility parameter, being evaluated the biological parameters: leaf consumption, weight of larvae in 4º instar and pupa with 24h, larval and pupal period and adult's longevity. After, were done leaves analysis iv nutritional of genotypes, and verified that quality nutrition not influenced the selection ...(Complete abstract, click electronic access below) / Mestre