Resumen El Xantosoma riedelianum, también llamado “mangarito” en Brasil, es una planta alimenticia no convencional (PANC) de la familia Araceae, nativa de América tropical. Se tomaron muestras de hojas de X. riedelianum con sintomas de mosaico, moteado y aclaramiento de venas en el municipio de Monte Alegre (Estado de São Paulo). Se realizó observaciones bajo un microscopio electrónico de transmisión, transmisión mecánica a plantas indicadoras, análisis serológicos (DAS-ELISA) y de RT-PCR indicando que los síntomas podrían estar relacionados con la presencia del virus de mosaico dasheen (DsMV, Potyvirus). Este es el primer reporte de DsMV en X. riedelianum en Brasil.

Abstract Xantosoma riedelianum, also called “mangarito” in Brazil, is an unconventional food plant (UFP) of the Araceae family native to tropical America. Foliar samples of the X. riedelianum showing mosaic, mottle and vein clearing symptoms were collected in the municipality of Monte Alegre (São Paulo State). Transmission electron microscope observations, mechanical transmission to experimental plants, serological (DAS-ELISA) and RT-PCR analyzes indicated that the symptoms could be associated with the presence of dasheen mosaic virus (DsMV, Potyvirus). This is the first report of DsMV in X. riedelianum in Brazil.

RESUMO 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.

ABSTRACT 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.

Resumo: Esta publicação consiste em uma listagem de espécies de plantas, em ordem alfabética de seus nomes científicos, e dos vírus que foram encontrados naturalmente infetando-as em território brasileiro, com alguns comentários. O preparo de tal lista foi basedo nas publicações sobre vírus de plantas e as doenças que eles causam, colecionadas pelo autor de 1926 a 2018. Os vírus listados incluem aqueles já oficialmente reconhecidos pelo International Committee on Taxonomy of Viruses (ICTV), constantes do “Master Species List 2018”. Também estão incluídos vírus já caracterizados, aguardando oficialização pelo ICTV, e outros casos de possíveis viroses, cujo agente causal ainda não se acha adequadamente caracterizado. A listagem inclui 345 espécies de plantas, pertencentes a 74 famílias, que foram encontradas naturalmente infetadas por diferentes vírus. Fabáceas e Asteráceas foram as famílias que tiveram mais espécies infetadas por vírus, respectivamente 49 e 36. Até 2018, 213 espécies de vírus e 6 de viróides, pertencentes a 57 gêneros e 22 famílias e 6 ordens, oficialmente reconhecidas pelo ICTV, acham-se descritas no Brasil. Os gêneros Begomovirus e Potyvirus têm mais espécies representadas, com 45 e 42 respectivamente. Além das espécies identificadas e aceitas pelo ICTV, foram incluídas na lista 59 possíveis espécies que ainda aguardam oficialização, 113 vírus identificados a nível de gênero, quatro possíveis vírus isométricos e onze presumíveis viroses, de agentes etiológicos não confirmados. Foi incluída também uma lista reversa, com catalogação dos vírus e viróides descritos no Brasdil e suas respectivas plantas hospedeiras.

Abstract: A list of plant species, in alphabetical order by their scientific name, and the viruses found naturally infecting them in Brazilian territory, with some comments, was prepared . The production of such a list was based on a yearly catalog of publications on plant viruses collected by the author, from 1926 to 2018. Listed species of viruses were those recognized by the International Committee on Taxonomy of Viruses (ICTV), but also those characterized and still waiting official recognition, were included. Several cases of putative viral diseases were listed for historical reasons expecting to raise interest for their clarification. This list includes 345 plants species belonging to 74 families naturally infected by plant viruses in Brazil. Fabaceae and Asteraceae had most virus-infected species, respectively 49 and 36. Until 2018, a total of 213 plant virus and 6 viroid species belonging to 57 genera and 22 families and 6 orders, officially recognized by ICTV, were found naturally infecting these plants. Begomovirus and Potyvirus genera have most representatives, with 45 and 42 species, respectively. There are 59 characterized plant viruses, up to species level, described in Brazil waiting for the inclusion in the ICTV Master Species List. One hundred and thirteen viruses were identified up to genus level but still uncharacterized, while four putative isometric viruses and eleven presumptive viral diseases (“unidentified”) are included in the list. A reverse catalog, listing viruses and the plant species in which they were found is also included.

Citrus leprosis (CL) is a serious threat to the citrus industry, especially for sweet oranges. For a long time, Citrus spp. were considered the only susceptible hosts. However, other plant species were also found either experimentally or naturally to be susceptible to Citrus leprosis virus C (CiLV-C). To assess the experimental host range of CiLV-C, a large number of plant species were inoculated with Brevipalpus phoenicis, viruliferous to CiLV-C, under experimental conditions. Out of the 140 tested species (43 families), 59 species (24 families) developed localized chlorotic and/or necrotic lesions upon inoculation of leaves with viruliferous mites, and 40 species (18 families) of them yielded positive results for CiLV-C detection in at least one of the following assays: ELISA, RT-PCR, transmission electron microscopy and immunfluorescence. For those that developed lesions and yielded negative results in CiLV-C detection assays, the results may be attributed to the small number of lesions and their necrotic state with very little viral material. The fact that a considerable number of plant species are susceptible to the virus after mite inoculation brings up implications for the epidemiology, quarantine and evolution of the citrus leprosis pathosystem.

Sesame (Sesamum indicum L.) production in Paraguay has been severely affected by infection with Cowpea aphid-borne mosaic virus (CABMV), which causes a disease known locally as ka'are. Because very little is known about the epidemiology of this disease, a survey was performed in fields surrounding affected sesame plantations to identify CABMV-infected plants that may be acting as sources of inoculum. Samples from 48 plant species (symptomatic or asymptomatic, mostly spontaneous and a few cultivated) belonging to 17 families were evaluated by biological and serological assays. In a few select cases, confirmation of the infection was achieved by RT-PCR. The following species were found to be naturally infected by CABMV: Amaranthus hybridus, Arachis hypogaea, Crotalaria incana, Crotalaria juncea, Crotalaria spectabilis, and Vigna unguiculata. The absence of resistant/tolerant sesame cultivars along with the ineffectiveness of disease control through the chemical control of aphid vectors indicates that the only alternative available for disease management at present is the elimination and/or reduction of the sources of inoculum immediately before starting new plantations.

Citrus leprosis (CL) was first described in South America in the 1920's. It is considered similar to a disease first observed back to 1860 in Florida. It is a destructive disease characterized by localized lesions on the leaves, fruits and stems, which may lead to the death of the affected plant if left untreated. Around 1940, CL was demonstrated to be transmitted by Brevipalpus mites in Argentina. Because little information exists on the status of CL pathosystem in Argentina and Paraguay, a survey was made in several citrus growing areas of these countries from 2009 to 2011, to evaluate its presence and relevance as well as the identification of the virus and the mite vector. CL was found in most of the sweet orange and/or mandarin orchards in Paraguay (Departamentos de Boquerón, Concepción, San Pedro, Cordillera, Alto Paraná, Itapúa) and Argentina (Provincias de Misiones, Corrientes, Entre Ríos). Incidence was usually low. The causal virus was identified as Citrus leprosis virus C (CiLV-C) by RT-PCR, electron microscopy and immunofluorescence. In all the visited regions in Paraguay and the region of Montecarlo, Argentina, the mites collected in plants infected by CiLV-C were identified as B. phoenicis.

This work reports the in vitro expression of Citrus leprosis virus C (CiLV-C) putative coat protein (p29) and the production of a polyclonal antibody to be used as a tool for serological diagnosis of citrus leprosis. The ORF2/RNA1, corresponding to p29, was cloned in pET28a and transformed into Escherichia coli cells (BL21). Expression of p29 was induced in vitro and the protein was purified and used for immunization of rabbits to produce the polyclonal antibody. The anti p29 serum was shown to be highly specific to CiLV-C detection by immunological methods (Western blot, PTA-ELISA, tissue blot and in situ immunolocalization), without cross reaction with healthy citrus plants or other cytoplasmic and nuclear viruses transmitted by Brevipalpus mites. These results demonstrate that the antibody against CiLV-C p29 protein is highly specific for CiLV-C detection. In situ immunogold labeling assays on thin sections of sweet orange leaf cells infected by CiLV-C demonstrated that short, bacilliform particles present within cisternae of the endoplasmic reticulum were specifically labeled, confirming their viral nature. The dense cytoplasmic viroplasm was also heavily labeled indicating that it represents a site of p29 accumulation.

Citrus leprosis, caused by Citrus leprosis virus C (CiLV-C), is currently considered the most important viral disease in the Brazilian citrus industry due to the high costs required for the chemical control of its vector, the mite Brevipalpus phoenicis. The pathogen induces a non-systemic infection and the disease is characterized by the appearance of localized lesions on citrus leaves, stems and fruits, premature fruit and leaf drop and dieback of stems. Attempts were made to promote in vitro expression of the putative cell-to-cell movement protein of CiLV-C in Escherichia coli and to produce a specific polyclonal antibody against this protein as a tool to investigate the virus-plant-vector relationship. The antibody reacted strongly with the homologous protein expressed in vitro by ELISA, but poorly with the native protein present in leaf lesion extracts from sweet orange caused by CiLV-C. Reactions from old lesions were more intense than those from young lesions. Western blot and in situ immunolocalization assays failed to detect the native protein. These results suggest low expression of the movement protein (MP) in host tissues. Moreover, it is possible that the conformation of the protein expressed in vitro and used to produce the antibody differs from that of the native MP, hindering a full recognition of the latter.

Fungi are disease-causing agents in plants and affect crops of economic importance. One control method is to induce resistance in the host by using biological control with hypovirulent phytopathogenic fungi. Here, we report the detection of a mycovirus in a strain of Colletotrichum gloeosporioides causing anthracnose of cashew tree. The strain C. gloeosporioides URM 4903 was isolated from a cashew tree (Anacardium occidentale) in Igarassu, PE, Brazil. After nucleic acid extraction and electrophoresis, the band corresponding to a possible double-stranded RNA (dsRNA) was purified by cellulose column chromatography. Nine extrachromosomal bands were obtained. Enzymatic digestion with DNAse I and Nuclease S1 had no effect on these bands, indicating their dsRNA nature. Transmission electron microscopic examination of extracts from this strain showed the presence of isometric particles (30-35 nm in diameter). These data strongly suggest the infection of this C. gloeosporioides strain by a dsRNA mycovirus. Once the hypovirulence of this strain is confirmed, the strain may be used for the biological control of cashew anthracnose.

Fitoplasmas foram encontrados em vinca (Catharanthus roseus), uma planta tropical herbácea. Plantas exibindo sintomas de virescência, filodia e variegação foram coletadas nos estados de Minas Gerais e São Paulo. O fitoplasma foi transmitido por enxertia a partir de uma planta de vinca infectada para plantas sadias da mesma espécie, e por Cuscuta sp. para uma planta sadia de citrus. Isolados de fitoplasma encontrados em plantas de vinca no Brasil tiveram a região 16S rDNA sequenciada e foram classificados no grupo 16SrIX, subgrupo A, pertencente a espécie 'Candidatus P. phoenicium'.

Periwinkle (Catharanthus roseus), a tropical perennial plant, was found to be infected by a phytoplasma. Plants exhibiting virescence, phyllody and variegation symptoms were collected in the states of Minas Gerais and São Paulo, Brazil. The phytoplasma was transmitted by grafting from an infected periwinkle plant to healthy plants and by dodder to a citrus plant. Phytoplasma isolates from periwinkle plants from Brazil had the 16S rDNA gene sequenced and were classified in the 16SrIX group, subgroup A, belonging to the 'Candidatus P. phoenicium' species.

Em 2005 houve um relato da presença da leprose dos citros no Estado de Chiapas, ao sul do México, baseado em sintomatologia. Subsequentemente a doença foi constatada em pomares de laranjeiras doces no Estado de Tabasco, nas localidades de Huimanguillo e Cunduacan. Amostras de folhas com lesões lepróticas de laranjeiras Valencia ou Hamlin foram coletadas e posteriormente examinadas ao microscópio eletrônico e submetidas a ensaios de detecção molecular por RT-PCR usando primers específicos. Estudos ultraestruturais revelaram alterações citopatológicas típicas causadas pelo CiLV-C (partículas baciliformes curtas no lúmen do retículo endoplasmático e a presença de viroplasmas vacuolados e elétron-densos no citoplasma) e hipertrofia em algumas células do parênquima lacunoso. Ensaios de RT-PCR resultaram na amplificação, na maioria das amostras de folhas dessecadas, de fragmento de DNA de tamanho esperado. Ácaros Brevipalpus coletados nos pomares foram identificados como B. phoenicis. Ensaios de transmissão com este ácaro confirmaram seu papel como vetor do CiLV-C para laranja doce, mas não houve transmissão para limão, limão Volkameriana, citrange C35 e citrange Carrizo. Todos estes dados considerados em conjunto confirmam que CiLV-C está presente em Tabasco, México e que a leprose dos citros descrita em Chiapas é causada pelo CiLV-C.

Citrus leprosis was detected in sweet oranges in Chiapas, Mexico, in 2005 based on symptoms. The disease was soon after observed in sweet orange orchards at Huimanguillo and Cunduacan, state of Tabasco. Leaf samples of leprosis-affected Valencia or Hamlin sweet oranges were collected and subjected to ultrastructural examination and molecular detection of CiLV-C by RT-PCR. Cytopathic effects typical of CiLV-C infection as presence of short, baciliform particles in the endoplasmic reticulum cisternae and electron dense, vacuolated viroplasma in the cytoplasm, as well as hypertrophy of some spongy parenchyma cells were observed in the tissues of the leaf lesions. RT-PCR using specific primers for CiLV-C produced DNA fragments of the expected size. Brevipalpus mites were present in these orchards and identified as B. phoenicis, the known vector for CiLV-C. Transmission tests with these mites confirmed their role as leprosis vectors to sweet orange but not to lemon, Volkamerian lemon, C35 citrange and Carrizo citrange. These data confirm the presence of CiLV-C in Tabasco, Mexico and that the citrus leprosis found in Chiapas was caused by CiLV-C.

A doença leprose dos citros tem etiologia viral sendo o citrus leprosis virus seu agente etiológico. Demonstrou-se que há dois vírus distintos que causam sintomas de leprose em ci-tros: citoplasmático (CiLV-C) e o nuclear (CiLV-N). O objetivo desse estudo foi comparar as diferenças morfo-anatômicas nas lesões causadas por CiLV-C e por CiLV-N em laranjeira doce (Citrus sinensis (L.) Osbeck) 'Pêra'. As lesões foliares e dos frutos foram coletadas em Piracicaba/SP (tipo citoplas-mático) e em Monte Alegre do Sul/SP e Amparo/SP (tipo nuclear). As lesões foram fotografadas e em seguida fixadas em solução Karnovsky, desidratadas em série etílica, incluídas em historesina e secionadas em micrótomo rotativo. As lâminas foram coradas, analisadas e fotografadas. As lesões foliares e do fruto causadas pelos dois vírus eram morfologicamente distintas. Somente a lesão causada por CiLV-N apresentou três regiões bem definidas. Em ambas as lesões ocorreu acúmulo de substâncias lipídicas nas áreas necrosadas que se achavam envoltas por células com conteúdo protéico amorfo ou em gotas. Somente as lesões da folha e do fruto causadas pelo CiLV-N exibiram ductos traumáticos gomosos nos feixes vasculares.

The leprosis disease shows a viral etiology and the citrus leprosis virus is considered its etiologic agent. The disease may show two types of cytopatologic symptom caused by two virus: nuclear (CiLV-N) and cytoplasmic (CiLV-C) types. The aim of this study was to compare the morpho-anatomical differences in the lesions caused by leprosis virus-cytoplasmic and nuclear types in Citrus sinensis (L.) Osbeck 'Pêra'. Leaf and fruit lesions were collected in Piracicaba/São Paulo (cytoplasmic type) and Monte Alegre do Sul/São Paulo and Amparo/São Paulo (nuclear type). The lesions were photographed and then fixed in Karnovsky solution, dehydrated in a graded ethylic series, embedded in hydroxy-ethyl methacrylate resin (Leica Historesin), sectioned (5 μm thick), stained and mounted in synthetic resin. The digital images were acquired in a microscope with digital video camera. Leaf and fruit lesions caused by the two viruses were morphologically distinct. Only the lesion caused by CiLV-N virus presented three well-defined regions. In both lesions there was the accumulation of lipidic substances in necrotic areas that were surrounded by cells with amorphous or droplets protein. Only leaf and fruit lesions caused by CiLV-N virus exhibited traumatic gum ducts in the vascular bundles.

Foi feito um levantamento no estado do Amazonas, na região da capital Manaus, na base de exploração de petróleo de Urucu (700 km a sudoeste de Manaus) e em Presidente Figueiredo (100 km ao norte de Manaus) à procura de vírus transmitidos por ácaros Brevipalpus (VTrB) em diferentes espécies de plantas. Foram coletadas 33 espécies de plantas caracterizadas por lesões localizadas em folhas (manchas cloróticas, manchas anelares, manchas verdes em folhas senescentes) e pela presença de ácaros Brevipalpus (os quais foram coletados para identificação e avaliação de sua diversidade) em plantas cultivadas, ornamentais e silvestres. Fragmentos das lesões foram fixados no local e processados para microscopia eletrônica ultraestrutural e examinados em Piracicaba, SP. Foram constatados treze casos positivos de detecção de efeitos citopáticos do tipo citoplasmático ou nuclear de VTrB nas plantas coletadas em Manaus. Três deles parecem representar casos anteriormente descritos de VTrB em Hibiscus rosa sinensis, H. syriacus e Clerodendrum x speciosum. Presumíveis VTrB do tipo nuclear foram constatados em mancha clorótica em Piper callosum (Piperaceae), mancha clorótica anelar em Monstera deliciosa (Araceae), mancha clorótica em Ruellia chartacea (Acanthaceae), manchas cloróticas em Bidens sp. (Asteraceae), mancha verde em Allamanda chatartica (Apocynaceae), mancha clorótica em Gardenia sp. (Rubiaceae), mancha verde em Mussaenda erythrophylla (Rubiacea) e do tipo citoplasmático em mancha clorótica em Clerodendrum speciosissimum (Lamiaceae) e mancha anular em Arundina graminifolia (Orchidaceae). Todas estas plantas achavam-se naturalmente infestadas por Brevipalpus phoenicis.

A survey of Brevipalpus-transmitted plant viruses (BTrV) was carried out in the cities of Manaus and Presidente Figueiredo, and in the oil exploratory base of Urucu, Amazonas State, Central Amazon Basin, Brazil. The main characteristics considered during the survey were the occurrence of localized symptoms (chlorotic or brown spots, ringspots, green spots in senescent leaves) similar to those previously described for BTrV and infestation by Brevipalpus mites. For the evaluation of the infection by putative BTrV, small fragments of the leaf lesions were fixed in loco and later processed for ultrastructural electron microscopy at Piracicaba, SP. Thirteen plant hosts of presumed BTrV were found. Three of them probably represent previously described BTrV infecting Hibiscus rosa sinensis, H. syriacus and Clerodendrum x speciosum. For the first time we report cases of infection by putative BTrV of nuclear type in chlorotic spot in Piper callosum (Piperaceae), chlorotic ringspot in Monstera deliciosa (Araceae), chlorotic spot in Ruellia chartacea (Acanthaceae), chlorotic spot in Bidens sp. (Asteraceae), green spot in Allamanda chatartica (Apocynaceae), chlorotic spot in Gardenia sp. (Rubiaceae), chlorotic ringspot and green spot in Mussaenda erythrophylla. (Rubiaceae) and of cytoplasmic type in Clerodendrum speciosissimum (Lamiaceaae) and ringspots in Arundina graminifolia (Orchidaceae). All these plants were infested by Brevipalpu. phoenicis.

Os viróides são os menores fitopatógenos conhecidos, sendo constituídos de uma molécula de RNA fita simples, circular, com forte estrutura secundária. Possuem genomas que variam entre 246 e 401 nucleotídeos e, por não traduzirem proteínas próprias, são totalmente dependentes da célula hospedeira para sua replicação. São classificados em duas famílias e sete gêneros. O Citrus exocortis viroid (CEVd) pertence ao gênero Pospiviroid, enquanto o Hop stunt viroid (HSVd) é o único membro do gênero Hostuviroid, ambos pertencentes à família Pospiviroidae. Estes patógenos apresentam ampla distribuição mundial e infectam um grande número de hospedeiras. No Brasil, isolados do CEVd e do HSVd foram detectados em citros e videiras. Com o objetivo de caracterizar e estudar a variabilidade genética destes viróides, promoveu-se extração de RNA total de folhas de videira Vitis vinifera 'Cabernet Sauvignon' e V. labrusca 'Niagara Rosada' provenientes de Bento Gonçalves, RS, e RT-PCR com oligonucleotídeos específicos para os cinco viróides já descritos em videira [HSVd, CEVd, Grapevine yellow speckle viroid 1 (GYSVd-1), Grapevine yellow speckle viroid 2 (GYSVd-2) e Australian grapevine viroid (AGVd)]. Amostras de folhas de Citrus medica infectadas pelo CEVd provenientes de São Paulo também foram analisadas. Os fragmentos de DNA amplificados foram eluídos, clonados e seqüenciados. As análises das seqüências revelaram que as amostras de videira estavam duplamente infectadas com o CEVd e HSVd. As análises filogenéticas mostraram que os clones de HSVd de videira aqui caracterizados agruparam-se com outros variantes de videira, formando um grupo separado de um segundo formado por variantes de citros. Já os clones de CEVd de videira agruparam-se com isolados de citros e videira.

Viroids, non-protein-coding small (246-401 nt) circular single-stranded RNAs with autonomous replication, are currently classified into two families. Within the family Pospiviroidae, Citrus exocortis viroid (CEVd) belongs to the genus Pospiviroid while Hop stunt viroid (HSVd) is the single member of the genus Hostuviroid. These pathogens are distributed worldwide and infect a large number of hosts. In Brazil, isolates of CEVd and HSVd have been detected in both citrus and grapevine. To characterize and study the genetic variability of these viroids, total RNA from leaves of grapevine Vitis vinifera 'Cabernet Sauvignon' and V. labrusca 'Niagara Rosada' from Bento Gonçalves, RS, was used as a template for RT-PCR amplification with specific primers for the five viroids described infecting grapevines [HSVd, CEVd, Grapevine yellow speckle viroid 1 (GYSVd-1), Grapevine yellow speckle viroid 2 (GYSVd-2) and Australian grapevine viroid (AGVd)]. Leaf samples of Citrus medica infected with CEVd from São Paulo were also analyzed. The resulting products were separated by agarose gel electrophoresis and DNA fragments of the expected size were eluted, cloned and sequenced. The grapevine samples analyzed were doubly infected by CEVd and HSVd. A phylogenetic analysis showed that the Brazilian grapevine HSVd variants clustered with other grapevine HSVd variants, forming a specific group separated from citrus variants, whereas the Brazilian CEVd variants clustered with other citrus and grapevine variants.