Resumo

In January 2022 and April 2024, plants of Handroanthus heptaphyllus, designated HP22 and HP24, respectively, exhibiing symptoms of mosaic, leaf blistering, and ring spots were observed in the municipality of Piracicaba, São Paulo state, Brazil. Molecular analysis of plant HP22 revealed the presence of cucumber mosaic virus (CMV, genus Cucumovirus), and phylogenetic analysis classified it into subgroup IA. Additionally, CMV was identified using a plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) in both plants (HP22 and HP24). The virus of HP22 plant was mechanically transmitted to Handroanthus albus, H. heptaphyllus, H. impetiginosus, Tabebuia heptaphylla, and T. roseoalba plants, a transmission that PTA-ELISA confirmed. Furthermore, transmission was observed from Aphis gossypii to H. heptaphyllus and T. heptaphylla plants. Despite the absence of discernible symptoms, the presence of CMV was confirmed through PTA-ELISA. To the best of our knowledge, this represents the first report on the occurrence of CMV in H. heptaphyllus worldwide.

Resumo

Symptoms of severe vein clearing, leaf rolling, and blistering were observed in cassava plants in southwestern Bahia State, Brazil. The plants were collected, vegetatively propagated, and kept in a greenhouse. Leaf samples tested positive for begomovirus infection by Polymerase chain reaction (PCR). Complete nucleotide sequences of DNA-A and DNA-B of isolate PSLDV-Man04 revealed 99.89 % and 96.2 % identity, respectively, with the bipartite begomovirus passionfruit severe leaf distortion virus (PSLDV) genome. This PSLDV isolate was experimentally transmitted to two and four of the five cassava plants and ten passion fruit plants, respectively, inoculated with Bemisia tabaci Middle East-Asia Minor 1 (MEAM1). This is the first report of the natural infection of cassava plants by the PSLDV begomovirus in Brazil.(AU)

Resumo

Zinnia sp. and hairy beggartick (Bidens pilosa) plants exhibiting symptoms of possible virus infection were found in the municipality of Santa Bárbara d'Oeste, São Paulo State, Brazil. Flexuous filamentous particles and cytoplasmatic inclusions typical of potyvirus infection were observed by transmission electron microscopy, respectively, in leaf extracts and cells of symptomatic leaves. Infection of both plants with bidens mottle virus (BiMoV) was confirmed by RT-PCR using potyvirus universal primers, followed by nucleotide sequencing of the amplicons. The nearly complete genome sequence of the Brazilian isolate, named BiMoV-BR, is 9700 nucleotides long and shares 95.6 % identity with the corresponding nucleotide sequence of a BiMoV isolate from the United States. BiMoV-BR was mechanically transmitted and caused systemic infection on plants of Zinnia sp., hairy beggarstick, sunflower (Helianthus annuus), and lettuce (Lactuca sativa). Myzus persicae transmitted the virus to Zinnia sp. plants with efficacy of 8 % and 42 %, using one and ten aphids per plant, respectively. This is the first detection of BiMoV in Brazil. Further studies are necessary to evaluate the distribution of this potyvirus in the country.

Resumo

Sunflower (Helianthus annuus) plants showing symptoms of chlorosis, mosaic, chlorotic ringspot, and necrosis on younger leaves were found in a small experimental plot in Piracicaba, in the state of São Paulo, Brazil. Preliminary examinations by transmission electron microscopy of symptomatic leaf tissue revealed flexuous filamentous particles 13-15 nm wide and 700-750 nm long, and cytoplasmatic cylindrical inclusions typical of those found in plant cells infected by members of the Potyvirus genus. Total RNA extracted from symptomatic leaves and subjected to RT-PCR followed by partial nucleotide sequencing confirmed the presence of a potyvirus in the affected plants, which was identified as sunflower chlorotic mottle virus (SuCMoV), a member of the Sunflower chlorotic mottle virus (genus Potyvirus, family Potyviridae) species. Mechanical transmission assays with extracts of symptomatic sunflower leaves reproduced the original symptoms in sunflowers, mosaic symptoms in Zinnia elegans, and chlorotic local lesions in Chenopodium amaranticolor and C. quinoa. Sunflower and zinnia plants became infected after aphid transmission experiments with Myzus persicae. RT-PCR tests using specific primers for SuCMoV confirmed the presence of this virus in experimentally infected plants, meeting the criteria of Koch's postulate. This is the first report of SuCMoV infecting sunflower plants in Brazil.

Resumo

In the last decades, the high incidence of viruses transmitted by whiteflies has become a problem in the tomato fields, threatening, more recently, the potato crops. The present study carried out a survey of begomoviruses and criniviruses in tomato and potato crops, from 2015 to 2018, in the municipalities of Araucária, Campo do Tenente, Campo Largo, Contenda, Lapa, Faxinal, Morretes, Reserva, Castro, Palmeira and São Mateus do Sul, in Paraná State, Brazil. Total DNA and RNA from leaves were extracted and used as templates to detect, respectively, begomoviruses by PCR and criniviruses by RT-PCR. Out of 215 tomato samples, 14 from Faxinal were infected by crinivirus. The other tomato samples and 243 potato samples showed negative results for begomovirus and crinivirus. Results indicated a low incidence (6.5%) of crinivirus infecting tomato crops in Paraná State, and the nucleotide sequence of one amplified fragment shared 99.71% identity with tomato chlorotic virus (ToCV).

Nas últimas décadas, a alta incidência de vírus transmitidos por mosca-branca tornou-se um problema nos campos de tomateiros, ameaçando, mais recentemente, a cultura da batateira. O presente trabalho teve como objetivo realizar um levantamento de begomovírus e crinivírus em lavouras de tomateiro e batateira nos municípios de Araucária, Campo do Tenente, Campo Largo, Contenda, Lapa, Faxinal, Morretes, Reserva, Castro, Palmeira e São Mateus do Sul, no Estado do Paraná, Brasil, de 2015 à 2018. DNA e RNA totais de folhas foram extraídos e utilizados como molde para detectar begomovírus por PCR e crinivírus por RT-PCR. Das 215 amostras de tomateiros coletadas, 14 provenientes de Faxinal estavam infectadas por crinivírus. As demais amostras de tomateiro e as 243 amostras de batateira analisadas apresentaram resultados negativo para begomovírus e crinivírus. Os resultados indicaram baixa incidência (6,5%) de crinivírus infectando lavouras de tomateiros no Estado do Paraná e a sequência de nucleotídeos de um amplicon apresentou 99,71% de identidade com o crinivírus tomato chlorotic virus (ToCV).

Resumo

The habanero chilli pepper, Capsicum chinense is an important crop in the Amazon Basin, mainly grown by small-scale producers. Capsicum chinense plants in an experimental field in the northern Brazilian state of Amazonas were found exhibiting characteristic symptoms of viral infection. Leaf sap from symptomatic plants examined under a transmission electron microscope revealed the presence of elongated flexuous particles and isometric particles. Using molecular assays, the viruses were identified as pepper yellow mosaic virus (PepYMV) and cucumber mosaic virus (CMV). Aphids, identified as Aphis gossypii, were found colonizing the C. chinense plants in the field and may be the vector for both PepYMV and CMV. We report the first occurrence of these viruses infecting C. chinense in the state of Amazonas.

A pimenta-de-cheiro, Capsicum chinense é uma cultura importante na Bacia Amazônica, cultivada principalmente por pequenos produtores. Plantas de C. chinense em um campo experimental localizado no norte do estado brasileiro do Amazonas, foram encontradas apresentando sintomas característicos de infecção viral. Extratos de amostras de folhas sintomáticas examinados ao microscópio eletrônico de transmissão revelaram a presença de partículas alongadas e flexuosas e de partículas isométricas. Análises moleculares permitiram identificar a presença do pepper yellow mosaic virus (PepYMV) e do cucumber mosaic virus (CMV). Pulgões, identificados como Aphis gossypii foram encontrados colonizando pimenteiras-de-cheiro neste campo experimental e podem representar o provável vetor de PepYMV e CMV. Este trabalho relata a primeira ocorrência desses vírus infectando C. chinense no estado do Amazonas.

Resumo

Severe mosaic symptoms, accompanied by yellow spots, abnormally small leaves, fruit malformation and cracking, reduced plant growth, and high levels of whitefly (Bemisia tabaci MEAM1) infestation were observed in passionflower (Passiflora edulis) orchards in southwestern Bahia, Brazil. The aim of this work was to identify the species of begomovirus infecting the passionflowers, its prevalence in southwestern Bahia, and the spatial and temporal dynamics of the disease. Leaf samples from symptomatic plants collected at 57 orchards located in ten counties were evaluated by PCR for begomovirus infection. Complete nucleotide sequences of DNA-A for two isolates revealed 97 % identity with Passionfruit severe leaf distortion virus (PSLDV). The occurrence of PSLDV in 57 orchards was evaluated based on the presence of characteristic disease symptoms. Approximately 235,000 visually assessed plants exhibited symptoms characteristic of begomovirus infection. Epidemiological studies, conducted in two orchards in Dom Basílio County, showed that disease progress was relatively slow until 121 days after transplanting (DAT), but more rapid in the following 35 days, reaching 100 % infected plants by 156 DAT. The exponential model was fitted to the temporal dynamic of the disease for both areas. An aggregated pattern of diseased plants was predominant for almost all evaluations. It is possible that the primary and secondary spread of the pathogen occurred concurrently during the epidemic progression in both areas, especially late in the season. Containment measures to prevent the virus and the vector from spreading to other passionfruit producing areas in Brazil should be implemented.

Resumo

Zucchini yellow mosaic virus (ZYMV) causes substantial economic losses in cucurbit crops. Although ZYMV has been present in Brazil for more than 20 years, there is little information about the biological and molecular characteristics of the isolates found in the country. This study aimed to characterize the experimental hosts, pathotypes and genetic diversity of a collection of eleven Brazilian ZYMV isolates within the coat protein gene. For biological analysis, plant species from Amaranthaceae, Chenopodiaceae, Cucurbitaceae, Fabaceae, Solanaceae, and Pedaliaceae were mechanically inoculated and pathotypes were identified based on the reaction of a resistant Cucumis melo, accession PI414723. All of the cucurbit species/varieties and Sesamum indicum were systemically infected with all isolates. The nucleotide sequence variability of the coat protein gene ranged from 82 % to 99 % compared to the corresponding sequences of ZYMV isolates from different geographical locations. No recombination event was detected in the coat protein gene of the isolates.