Search

Brevipalpus yothersi egg morphology Details of external eggs morphology could be followed under SEM. Transverse streaks in the outer layer of the eggs called carenas (Rodrigues and Machado 1999) (Figure 2a) and a fold-like structure in the equatorial region of the egg (Figure 2b). An external globular structure were observed in studies by Rodrigues and Machado (1999). However, it was observed only in eggs with a more advanced development time but morphologically different from the one found in our study. Eggshells frequently broke during fixation in Carnoy’s solution, allowing for observation of the internal structure of eggs. Additionally, channels similar to small perforations were seen extending between the shell and intermediate lamella (Figure 3). These channels may be associated with the respiratory tract of the embryo. Such structures were also observed by Dittrich (1971) in studies with T. urticae, and they have been shown to give mites protection against desiccation and gas exchange., Published as part of Sinico, Thaís Elise, Nunes, Maria Andréia, Kitajima, Elliot Watanabe, Cunha, Bruna Aparecida & Novelli, Valdenice Moreira, 2022, Notes on the embryological development of the Brevipalpus yothersi (Acari: Tenuipalpidae), pp. 113-119 in Acarologia 62 (1) on page 116, DOI: 10.24349/0gr3-3a6b, http://zenodo.org/record/7160131, {"references":["Rodrigues J. C. V., Machado M. A. 1999. Notes on a probable respiratory apparatus in eggs of Brevipalpus phoenicis (Acari: Tenuipalpidae). Int. J. Acarol., 25: 231 - 234. https: // doi. org / 10.1080 / 01647959908684157","Dittrich V. 1971. Electron-microscopic studies of the respiratory mechanism of spider mite eggs. Ann. Entomol. Soc. Am., 64: 1134 - 1143. https: // doi. org / 10.1093 / aesa / 64.5.1134"]}

Citrus leprosis (CL) is a viral disease currently affecting citrus orchards in Latin America. It causes a non-systemic infection that produces necrotic and chlorotic spots in leaves, stems and fruits, reducing citrus crop yield and leading to the death of younger trees. Viruses causing CL are assigned to two genera: Cilevirus [bipartite ss(+) RNA] and Dichorhavirus [bipartite ss(-) RNA]. Prevalent CL in orchards from Mexico to Argentina is the cytoplasmic type of the disease (CL-C) produced by the cilevirus citrus leprosis virus C (CiLV-C). CiLV-C population is genetically subdivided into two clades, which have a contrasted geographic distribution. While viruses from one clade seem to be confined to commercial areas in the State of São Paulo, Brazil, those from the other occur all over the continent. In Colombia, CL-C is also caused by another cilevirus, CiLV-C2, whose genome shares only 55% nucleotide identity with CiLV-C. Nuclear types of leprosis (CL-N), caused by dichorhaviruses, seem to have severely affected citrus orchards in Florida, USA, a century ago, and have been recently characterized in Brazil, Mexico and Colombia. While in the two latter countries citrus strains of orchid fleck virus (OFV-citrus) occur in commercial orchards, in Brazil, citrus leprosis virus N (CiLV-N) and citrus chlorotic spot virus (CiCSV) are the causal agents for CL-N so far, which are restricted to small non-commercial areas. Both, CiLV-N and CiCSV, display a relatively distant phylogenetic relationship with OFV (< 65% nucleotide sequence identity). All viruses causing CL are persistently transmitted by false spider mites of the genus Brevipalpus, but with distinguishing features for cilevirus and dichorhavirus. A large spectrum of citrus commercial species and hybrids are prone to CL infection, and the apparent symptoms, at least in sweet oranges infected by CiLV-C, seem to be the outcome of a hypersensitive-like response. Studies based on molecular epidemiology and omics approaches are providing the necessary insights to generate more effective and safer control strategies of CL.

Citrus leprosis (CL) is a viral disease currently affecting citrus orchards in Latin America. It causes a non-systemic infection that produces necrotic and chlorotic spots in leaves, stems and fruits, reducing citrus crop yield and leading to the death of younger trees. Viruses causing CL are assigned to two genera: Cilevirus [bipartite ss(+) RNA] and Dichorhavirus [bipartite ss(-) RNA]. Prevalent CL in orchards from Mexico to Argentina is the cytoplasmic type of the disease (CL-C) produced by the cilevirus citrus leprosis virus C (CiLV-C). CiLV-C population is genetically subdivided into two clades, which have a contrasted geographic distribution. While viruses from one clade seem to be confined to commercial areas in the State of São Paulo, Brazil, those from the other occur all over the continent. In Colombia, CL-C is also caused by another cilevirus, CiLV-C2, whose genome shares only 55% nucleotide identity with CiLV-C. Nuclear types of leprosis (CL-N), caused by dichorhaviruses, seem to have severely affected citrus orchards in Florida, USA, a century ago, and have been recently characterized in Brazil, Mexico and Colombia. While in the two latter countries citrus strains of orchid fleck virus (OFV-citrus) occur in commercial orchards, in Brazil, citrus leprosis virus N (CiLV-N) and citrus chlorotic spot virus (CiCSV) are the causal agents for CL-N so far, which are restricted to small non-commercial areas. Both, CiLV-N and CiCSV, display a relatively distant phylogenetic relationship with OFV (< 65% nucleotide sequence identity). All viruses causing CL are persistently transmitted by false spider mites of the genus Brevipalpus, but with distinguishing features for cilevirus and dichorhavirus. A large spectrum of citrus commercial species and hybrids are prone to CL infection, and the apparent symptoms, at least in sweet oranges infected by CiLV-C, seem to be the outcome of a hypersensitive-like response. Studies based on molecular epidemiology and omics approaches are providing the necessary insights to generate more effective and safer control strategies of CL.

O gênero botânico Clerodendrum pertence à família Lamiaceae e compreende várias espécies ornamentais, Manchas cloróticas e necróticas em folhas de coração-sangrento foram observadas pela primeira vez em um jardim de Piracicaba, SP, associadas à infestação com Brevipalpus phoenicis (Acari: Tenuipalpidae). Exames de secções de tecidos das lesões foliares ao microscópio eletrônico revelaram ocorrência de efeitos citopáticos do tipo nuclear e concluiu-se que os sintomas eram causados por um vírus transmitido por Brevipalpus (VTB), o qual foi designado de mancha clorótica de Clerodendrum (Clerodendrum Chlorotic Spot Virus- ClCSV). O ClCSV é transmitido mecanicamente de coração-sangrento para coração-sangrento. Em ensaios preliminares foi transmitido por B. phoenicis e mecanicamente para várias outras plantas, além da ocorrência de sua disseminação natural por este ácaro para outras espécies. Visando complementar a caracterização do ClCSV foram feitos estudos sobre alterações anatômicas em folhas de plantas infectadas pelo ClCSV. Foram examinadas secções histológicas de folhas sadias e infectadas pelo ClCSV de C. x speciosum e de outras hospedeiras como Hibiscus schizopetalus, Salvia leucantha, Malvaviscus arboreus e Annona muricata. Constatou-se que o ClCSV causa alterações celulares semelhantes nas diferentes hospedeiras e os sintomas causados por este vírus são similares aos causados por outros vírus transmitidos por Brevipalpus como o vírus da leprose dos citros citoplasmático (Citrus Lepros Virus Cytoplasmic- CiLV-C) e nuclear (Citrus Leprosis Virus Nuclear- CiLV-N), mancha anular do cafeeiro (Coffee Ringspot Virus- CoRSV), mancha anular de Solanum violaefolium (Solanum violaefolium Ringspot Virus- SvRSV) e "Orchid Fleck Vírus" (OFV), representadas por hipertrofia e hiperplasia frequentemente acompanhadas de necrose nos tecidos do parênquima paliçádico e lacunoso. The botanical genus Clerodendrum belongs to the family Lamiaceae and includes several ornamental species. Necrotic and chlorotic spots on leaves of bleeding heart were observed for the first time in a residential garden from Piracicaba Municipality, São Paulo State, Brazil, associated with an infestation by the flat mite Brevipalpus phoenicis (Acari: Tenuipalpidae). Tissue section analysis of the leaf lesions under transmission electron microscope showed characteristic cytopathic effects of the nuclear type, indicating that the symptoms were caused by a Brevipalpus-transmitted virus (BTV), named Clerodendrum Chlorotic Spot Virus (ClCSV). This virus was shown to be transmitted mechanically and by B. phoenicis to several plant species. In order to complete ClCSV characterization, anatomical changes in the leaf lesions of ClCSV-infected leaves were evaluated. Histological sections of healthy, control leaves and leaf lesions of ClCSV-infected plants of C. x speciosum, Hibiscus schizopetalus, Salvia leucantha, Malvaviscus arboreus and Annona muricata were analyzed. ClCSV infection resulted in similar tissue alterations caused by other BTV as Citrus Leprosies Virus Cytoplasmic (CiLV-C) and Nuclear (CiLV-N), Coffee Ringspot Virus (CoRSV), Solanum violaefolium Ringspot Virus (SvRSV) and Orchid Fleck Virus (OFV). Such symptoms consisted of hypertrophy and hyperplasia frequently followed by necrosis in palisade and spongy parenchyma tissues.

The first cases of ornamental plants found infected by Brevipalpus transmitted viruses (BTV) were described in the 1990's from the region of Piracicaba, State of São Paulo, Brazil; subsequent cases were from other regions in the country and other American countries. Currently, 37 ornamental plant species (for the sake of simplicity, orchids being considered as a single species), belonging to 18 families of dicotyledons, have been reported hosting BTV. Because of the non systemic type of infection of these viruses, the localized diseases they cause are unimportant usually, but they have the potential to cause economic losses if severe outbreaks of Brevipalpus mite populations occur. Some ornamentals may serve as reservoirs to BTV known to cause serious damage to food crops as Citrus leprosis virus- cytoplasmic type (CiLV-C), passion fruit green spot virus (PFGSV) and Coffee ringspot virus (CoRSV). Os primeiros casos de plantas ornamentais encontradas naturalmente infetadas por vírus transmitidos por Brevipalpus (Acari: Tenuipalpidae) (VTB) foram registrados nos anos 1990 na região de Piracicaba, Estado de São Paulo, e ocorrências subseqüentes foram observadas em várias outras regiões do país e de outros países das Américas. Atualmente acham-se relatadas 37 espécies de ornamentais (para efeito de simplificação, orquídeas foram consideradas como única espécie) pertencentes a 18 famílias botânicas. Pelo fato de causarem apenas infecções localizadas, geralmente nas folhas, VTB em ornamentais não causam preocupações aos produtores, mas potencialmente podem causar perdas econômicas se ocorrerem explosões populacionais do ácaro vetor. Plantas ornamentais podem servir de reservatório de VTB de importância econômica como os vírus da leprose dos citros-tipo citoplasmático (CiLV-C), da mancha verde do maracujá (PFGSV) e da mancha anular do cafeeiro (CoRSV).

Chlorotic spots have been observed in plants of Clerodendrum x speciosum growing in residential gardens and parks in Piracicaba, SP, Brazil. Thin sections of diseased tissues revealed characteristic cytopathic effects of the nuclear type of the Brevipalpus (Acari: Tenuipalpidae) mite-transmitted viruses (BTrV). Brevipalpus mites, identified as B. phoenicis, infesting symptomatic C. x speciosum plants transmitted the pathogen to healthy C. x speciosum and to C. thomsonae, Gomphrena globosa, Hibiscus cannabinus, H. coccineus, H. schizopetalus, Salvia leucantha, Spathiphyllum wallasi and Tetragonia expansa causing chlorotic spots on their leaves. Mechanical inoculation using leaf extracts from infected C. x speciosum resulted in chlorotic spots on inoculated C. x speciosum, Chenopodium quinoa, C. amaranticolor, G. globosa, H. cannabinus, H. coccineus and T. expansa leaves. C. amaranticolor and C. quinoa kept at 28 - 30°C became systemically infected. The same cytopathic effects caused by the nuclear type of BTrV were seen in tissues from all infected test plants by electron microscopy. The virus was purified from systemically infected leaves of C. amaranticolor and C. quinoa. A polyclonal antiserum obtained from an immunized rabbit presented a strong reaction with the homologous antigen in ELISA tests. The results suggest that this chlorotic spot disease of C. x speciosum is caused by a new species of the nuclear type of BTrV, tentatively named Clerodendrum chlorotic spot virus (ClCSV). Manchas cloróticas e necróticas foram observadas em folhas de várias plantas de coração-sangrento (Clerodendrum x speciosum) cultivadas em parques e jardins em Piracicaba, SP, associadas à infestação pelo ácaro tenuipalpídeo Brevipalpus phoenicis. Exames preliminares de secções de tecido das manchas cloróticas ao microscópio eletrônico revelaram a ocorrência de efeitos citopáticos característicos dos induzidos pelos vírus do tipo nuclear, transmitido por ácaros Brevipalpus (VTB). Brevipalpus phoenicis coletados de C. x speciosum sintomático e transferidos para plantas sadias de C. x speciosum reproduziram as lesões. O ácaro também transmitiu o patógeno para C. thomsonae, Gomphrena globosa, Hibiscus cannabinus, H. coccineus, H. schizopetalus, Salvia leucantha, Spathiphyllum wallasi e Tetragonia expansa, as quais exibiram manchas cloróticas e/ou necróticas. O vírus também foi transmitido mecanicamente para Chenopodium amaranticolor, C. quinoa, G. globosa, H. cannabinus, H. coccineus e T. expansa, além de C. x speciosum. Plantas de C. amaranticolor e C. quinoa mantidas a 28 - 30ºC desenvolveram infecção sistêmica. Em todos os tecidos sintomáticos das plantas-teste inoculadas, examinados ao microscópio eletrônico, foram encontrados efeitos citopáticos do tipo nuclear causado por VTB. O vírus foi purificado a partir de folhas com infecção sistêmica de C. amaranticolor e C. quinoa. Injeções de preparações purificadas em coelho geraram um anti-soro policlonal que reagiu especificamente com o antígeno homólogo em teste de ELISA. As evidências obtidas indicam que as manchas cloróticas do Clerodendrum estão associadas a um VTB do tipo nuclear, tentativamente denominado de vírus da mancha clorótica do Clerodendrum (Clerodendrum chlorotic spot virus- ClCSV).