Plant viruses transmitted by mites of the genus Brevipalpus are members of the genera Cilevirus, family Kitaviridae, or Dichorhavirus, family Rhabdoviridae. They produce non-systemic infections that typically display necrotic and/or chlorotic lesions around the inoculation loci. The cilevirus citrus leprosis virus C (CiLV-C) causes citrus leprosis, rated as one of the most destructive diseases affecting this crop in the Americas. CiLV-C is vectored in a persistent manner by the flat mite Brevipalpus yothersi. Upon the ingestion of viral particles with the content of the infected plant cell, virions must pass through the midgut epithelium and the anterior podocephalic gland of the mites. Following the duct from this gland, virions reach the salivary canal before their inoculation into a new plant cell through the stylet canal. It is still unclear whether CiLV-C multiplies in mite cells and what mechanisms contribute to its movement through mite tissues. In this study, based on direct observation of histological sections from viruliferous mites using the transmission electron microscope, we posit the hypothesis of the paracellular movement of CiLV-C in mites which may involve the manipulation of septate junctions. We detail the presence of viral particles aligned in the intercellular spaces between cells and the gastrovascular system of Brevipalpus mites. Accordingly, we propose putative genes that could control either active or passive paracellular circulation of viral particles inside the mites.

Citrus leprosis (CL) is one of the most devastating viral diseases of orchards, and industries correspondingly invest highly in the management and control of the virus vector. In Brazil, the disease is caused most predominantly by the citrus leprosis virus C (CiLV-C, Kitaviridae: Cilevirus), and also by citrus leprosis virus N (CiLV-N, Rhabdoviridae: Dichorhavirus). Both viruses are transmitted by false spider mites and at least three different species, Brevipalpus yothersi Baker, B. papayensis Baker, and B. phoenicis (Geijskes) sensu stricto, have been reported in citrus orchards. The main goal of this study was to evaluate the capacity of three Brevipalpus species to transmit citrus leprosis virus (cytoplasmic and nuclear types). The capacity of false spider mites to acquire the virus was accomplished using RT–PCR and the ability to inoculation the virus to host plants (common bean and sweet orange) was assessed via viral transmission assays. Common beans infested with B. yothersi and B. papayensis showed symptoms of CiLV-C in 87.5 and 17% of the plants assessed, respectively. In sweet orange, B. yothersi was exclusively able to inoculate CiLV-C, and around 83% of samples were symptomatic. Host plants infected with CiLV-N showed symptoms only when infested with B. phoenicis sensu stricto (s.s.). All the Brevipalpus species (Acari: Tenuipalpidae) were able to acquire both viruses (CiLV-C and CiLV-N), but not infect plants. These results suggest the existence of virus-vector specificity in the leprosis pathosystem, and this information will be critical for enhancing our further understanding of epidemiological features and disease management.

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É com muita satisfação que apresentamos o 17º Congresso de Iniciação Científica em Ciências Agrárias, Biológicas e Ambientais-17º CICAM. Com uma programação voltada a Inovação, procuramos selecionar temas que estimulassem o interesse dos jovens estudantes de iniciação científica e de pós-graduação por pesquisas nas áreas relacionadas a sanidades animal e vegetal, bem como em proteção ambiental. Além da importância desse conhecimento, nada melhor do que o tema "Nanotecnologia na agricultura/ambiente", para despertar o interesse dos participantes, dando início aos trabalhos do 17º CICAM. Contamos, ainda, com palestras ministradas por pesquisadores provenientes de renomadas Instituições de Pesquisa como, EMBRAPA, Institutos Biológico e Butantã, UFSCar, UNESP e USP e da empresa Sakata, que irão engrandecer o nosso evento com temas voltados para melhoramento genético convencional e por transgenia, vegetal e animal, visando ao controle de pragas e doenças; Produção de vacinas através do uso de vetores virais; Sequenciamento de terceira geração; Tratamento microbiológicos e oxidativos de resíduos industriais: Perspectivas e aplicações; Aplicação de ensaios com cultura de células em ambientes biorremediados; Internet of Things e a agricultura e, para fechar com chave de ouro, a palestra "Vida de cientista: os desafios de uma paixão pela natureza". No 17º CICAM, assim como em todas as outras edições, além dos 48 resumos aprovados pela Comissão Científica da revista O Biológico, teremos o prazer de receber alunos e pesquisadores de diversas instituições de ensino e pesquisa que, com certeza, contribuirão, não só com a divulgação de seus trabalhos, mas também com suas experiências. Contamos, portanto, com a valiosa participação de representantes do Centro

Mites of the Brevipalpus genus are economically important due to their role as vectors of plant viruses. Among them, B. yothersi is well studied because it is the recognized main vector of the citrus leprosis virus C (CiLV-C), the causal agent of citrus leprosis, which is one of the most damaging viral diseases in the citrus crops. However, studies of several aspects of the biology of B. yothersi are still scarce, including its embryology. We performed a descriptive embryonic development study of B. yothersi, utilizing light and scanning electron microscope to obtain biological information of this particular phytovirus vector. Distinct events were recorded, such as centering of the nucleus, mitotic divisions for primitive body formation and appendages, as well as the presence of channels inside the egg and their possible association with the respiratory tract. Here we provide the first notes about embryonic development of this important mite vector in the Americas.