Resposta de defesa de plantas cítricas a colonização de Brevipalpus yothersi (Acari: Tenuipalpidae) e infecção por citrus leprosis virus c (CiLV-C)
Carregando...
Arquivos
Data
2021-09-27
Autores
Kapp, Ana Beatriz Piai
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A citricultura é um dos setores mais importantes do agronegócio brasileiro. Contudo, é afetada por diversos problemas fitossanitários que aumentam seus custos de produção. Entre eles está a leprose dos citros, causada pelo citrus leprosis virus C (CiLV-C), e transmitida por Brevipalpus yothersi Baker (Acari: Tenuipalpidae). O manejo da leprose é realizado principalmente por meio do controle do ácaro vetor, sendo de extrema importância a compreensão acerca de seu patossistema. Diante isto, os objetivos deste trabalho foram elucidar respostas de colonização de B. yothersi em citros sob infestação primária com ácaros virulíferos e avirulíferos, verificar o comportamento desses indivíduos mediante a presença de lesões naturais (leprose) e artificiais (mistura de gesso) nas plantas, e associá-lo aos mecanismos de defesa vegetal durante a interação entre planta, ácaro e vírus. Para tanto, foi estabelecido um experimento em casa de vegetação sobre mudas cítricas, composto por três tratamentos que contavam com plantas sem a primeira infestação de ácaros (controle), plantas com a primeira infestação de ácaros avirulíferos e plantas com a primeira infestação de ácaros virulíferos, cada um com quinze repetições. Após trinta dias, foram coletadas amostras para avaliação dos genes marcadores das vias de ácido salicílico (PR1) e ácido jasmônico (PR4). Dez dias após a coleta, foi adicionada uma mistura de gesso para mimetização de lesões no controle e no tratamento com ácaros avirulíferos, e transferidos ácaros avirulíferos para todos os tratamentos. Uma nova coleta foi realizada após trinta e cinco dias, e seguiu-se a contagem de todas as fases do ácaro. Como resultados, foram obtidos que a primeira infestação com ácaros e tanto a presença de lesões de leprose, quanto a mistura de gesso favoreceram o crescimento populacional de B. yothersi após a segunda infestação, independentemente da presença de CiLV-C. Além disso, foi demonstrado que B. yothersi induz a via de ácido jasmônico nas plantas ao se alimentar, enquanto o CiLV-C a reprime, e induz a via de ácido salicílico como forma de beneficiar o ácaro vetor. Deste modo, esclarecemos valiosos aspectos acerca da interação entre C. sinensis, B. yothersi e CiLV-C, que constituem o patossistema da leprose dos citros.
Citriculture is one of the most lucrative sectors of Brazilian agribusiness. However, it is affected by several phytosanitary problems that increase its production costs. Between them is citrus leprosis, caused by citrus leprosis virus (CiLV-C), and transmitted by Brevipalpus yothersi Baker (Acari: Tenuipalpidae). The leprosis management is performed mainly through the vector mite control, and understanding its pathosystem is extremely important. Thus, the objectives of this study were to elucidate colonization responses of B. yothersi in citrus under primary infestation with viruliferous and aviruliferous mites, to verify the behavior of these individuals through the presence of natural (leprosis) and artificial (gypsum mixture) lesions in the plants, and associate it with plant defense mechanisms during the interaction between plant, mite, and virus. Therefore, an experiment was established in a greenhouse on citrus seedlings, consisting of three treatments that had plants without the primary infestation of mites (control), plants with the primary infestation of aviruliferous mites, and plants with the primary infestation of viruliferous mites, each one with fifteen repetitions. After thirty days, samples were collected to evaluate the marker genes of the salicylic acid (PR1) and jasmonic acid (PR4) pathways. Ten days after collection, a gypsum mixture was added to mimic lesions in the control treatment and aviruliferous treatment, and aviruliferous mites were transferred to all treatments. After thirty-five days, the leaves were collected again, and the counting of all mite stages was performed. As a result, the primary infestation with mites and the presence of leprosis lesions and gypsum mixture favored the population growth of B. yothersi after the second infestation, regardless of the presence of CiLV-C. Furthermore, it was shown that B. yothersi induces the jasmonic acid pathway in plants when feeding, while CiLV-C represses it, and induces the salicylic acid pathway to benefit the vector mite. In this way, we clarify valuable aspects about the interaction between C. sinensis, B. yothersi and CiLV-C, which constitute the pathosystem of citrus leprosis.
Citriculture is one of the most lucrative sectors of Brazilian agribusiness. However, it is affected by several phytosanitary problems that increase its production costs. Between them is citrus leprosis, caused by citrus leprosis virus (CiLV-C), and transmitted by Brevipalpus yothersi Baker (Acari: Tenuipalpidae). The leprosis management is performed mainly through the vector mite control, and understanding its pathosystem is extremely important. Thus, the objectives of this study were to elucidate colonization responses of B. yothersi in citrus under primary infestation with viruliferous and aviruliferous mites, to verify the behavior of these individuals through the presence of natural (leprosis) and artificial (gypsum mixture) lesions in the plants, and associate it with plant defense mechanisms during the interaction between plant, mite, and virus. Therefore, an experiment was established in a greenhouse on citrus seedlings, consisting of three treatments that had plants without the primary infestation of mites (control), plants with the primary infestation of aviruliferous mites, and plants with the primary infestation of viruliferous mites, each one with fifteen repetitions. After thirty days, samples were collected to evaluate the marker genes of the salicylic acid (PR1) and jasmonic acid (PR4) pathways. Ten days after collection, a gypsum mixture was added to mimic lesions in the control treatment and aviruliferous treatment, and aviruliferous mites were transferred to all treatments. After thirty-five days, the leaves were collected again, and the counting of all mite stages was performed. As a result, the primary infestation with mites and the presence of leprosis lesions and gypsum mixture favored the population growth of B. yothersi after the second infestation, regardless of the presence of CiLV-C. Furthermore, it was shown that B. yothersi induces the jasmonic acid pathway in plants when feeding, while CiLV-C represses it, and induces the salicylic acid pathway to benefit the vector mite. In this way, we clarify valuable aspects about the interaction between C. sinensis, B. yothersi and CiLV-C, which constitute the pathosystem of citrus leprosis.
Descrição
Palavras-chave
Ácaro de plantas, Brevipalpus yothersi, CiLV-C, Citrus sinensis, Laranja doenças e pragas