Zoysia japonica , in Brazil, is commonly infected by Rhizoctonia solani ( R. solani ) in humid and cool weather conditions. Eight isolates of R. solani , previously identified as belonging to the AG2-2 LP anastomosis group, isolated from samples from large path symptoms, were collected from three counties in São Paulo state (Brazil) and investigated for the presence of mycoviruses. After detection of double-strand RNA (dsRNA) in all samples, RNA_Seq analysis of ribosomal RNA-depleted total RNA from in vitro cultivated mycelia was performed. Forty-seven partial or complete viral unique RNA dependent-RNA polymerase (RdRp) sequences were obtained with a high prevalence of positive sense ssRNA viruses. Sequences were sufficiently different from the first match in BLAST searches suggesting that they all qualify as possible new viral species, except for one sequence showing an almost complete match with Rhizoctonia solani dsRNA virus 2, an alphapartitivirus. Surprisingly four large contigs of putative viral RNA could not be assigned to any existing clade of viruses present in the databases, but no DNA was detected corresponding to these fragments confirming their viral replicative nature. This is the first report on the occurrence of mycoviruses in R. solani AG2-2 LP in South America.

Necrotic lesions surrounded by yellow areas on leaves followed by stem necrosis were observed on chrysanthemum plants cultivated in Atibaia, Sào Paulo State, Brazil. The host range, in vitro properties and particle morphology of the causal virus were typical of a Tospovirus. Serological studies demonstrated that the virus differed from tomato spotted wilt. tomato chlorotic spot, groundnut ringspot and inpatiens necrotic spot Tospoviruses. The virus isolate is thus possibly a representativeof a new serogroup of a new virus.

Badnavirus in Bougainvillea spectabilis showing virus-like symptoms was identified by the presence of bacilliform particles, measuring 125-130 ¥ 30-40 nm in leaf-dip preparations and by analysis of its putative open reading frame 3 sequence. The virus, tentatively named Bougainvillea bacilliform virus (BBV), had the highest identities (up to 60%) with Spiraea yellow leaf spot virus, Gooseberry vein banding associated virus, Taro bacilliform virus, and Citrus yellow mosaic virus. In phylogenetic analysis, BBV clustered with Badnavirus putative species. Attempts to transmit the virus to several hosts failed. This is the first report of a new Badnavirus detected in Bougainvillea.

Authentication of cell lines is of paramount importance to validate the results from their use in biomedical research. Although isoenzyme polymorphism is the standard method, molecular methods based on mitochondrial DNA (mtDNA) have been developed to replace it. The aim of this study was the improvement of our isoenzyme electrophoretic analysis and the validation of one molecular technique targeted at mtDNA for the authentication of our animal cell lines. The combined method of cellular lysing through osmotic shock, followed by freezing-thawing in N 2 to obtain isoenzyme extracts, and with 42 × 10 6 cells maintained the best efficiency. The superior electrophoretic conditions were PAGE run at 200 V. All cell lines had isoenzymatic mobility corresponding to their species to lactate dehydrogenase, malatedehydrogenase, and glucose-6-phosphate dehydrogenase isoenzymes, and could be distinguished from each other. Two molecular techniques based on mtDNA were tested, one on the cytochrome b gene and other on cytochrome c oxidase I subunit gene. Due to difficulties in distinguishing all cell lines using only one these techniques, we merged the primers of two methods in such a way that there was a sufficient differentiation of all DNA fragments. The sequencing of these PCR products was also performed to validate these data.

Petunia plants collected in SaÄ o Paulo City, Brazil, showing yellow mosaic, were naturally infected by a virus of the genus Tobamovirus identi®ed according to particle morphology and size, host range, physical properties and cytopathic eects. On the basis of serological properties, amino acid composition and nucleotide sequence of the coat protein gene, the virus isolate was identi®ed as a new strain of Tobacco mosaic virus (TMV-p). A conspicuous feature of this virus infection is the presence of virus-like particles within the mitochondrial matrix. The data from phylogenetic analysis indicate that TMV-p belongs to subgroup 1 of the genus Tobamovirus.

This retrospective study concerned 41 infectious bursal disease virus (IBDV) isolates obtained from Brazilian broiler and layers flocks by reverse transcription-polymerase chain reaction. Twenty-five of them were identified as very virulent (vv) by restriction enzyme analysis and by further nucleotide and phylogenetic analysis. All of them had the typical amino acid residues, and all clustered in a phylogenetic tree with the vvIBDV strains. Four amino acid substitutions, at positions D213N, G254D, S317R, and D323E, were common to 3 vv isolates, Br/03/DB, Br/03/CK, and Br/04/CR, and differed from other vv isolates and strains. These isolates came from the same locale, but were collected in different years, indicating that the vvIBDVs circulating on Brazilian farms are undergoing slight but continuous exchanges.

Petunia plants from a nursery in the State of Rio Grande do Sul, Brazil, showed pronounced vein banding and contained isometric particles with diameters of approximately 45 and 30 nm. The larger ones apparently represent a caulimovirus, while the smaller ones, which included both empty shells and full particles, were identified as those of a new tymovirus for which we propose the name Petunia vein banding virus (PetVBV). Originally, PetVBV was transmitted only with difficulty to healthy petunia plants. However, from an experimentally infected petu-nia, it was later readily transmitted also to Nicotiana benthamiana and Nicandra physalodes, but not to other species in the Solanaceae or other plant families. It produces cytopathic effects typical for tymovirus infections. Its coat protein shows approximately 65% amino acid sequence identity with those of Eggplant mosaic and Andean potato latent viruses, to which it is also serologically more closely related than to any other tymoviruses.

O mercado de flores e plantas ornamentais vem crescendo consideravelmente nos últimos anos, no Brasil. É importante destacar que, paralelamente ao crescimento das exportações, um aumento na importação de flores e plantas ornamentais vem sendo observado. Porém, apesar da introdução de novas espécies e variedades, são poucos os relatos de doenças causadas por vírus, possivelmente porque alguns induzem infecção latente, dificultando sua identificação. Assim, este trabalho teve como objetivo identificar biológica, sorológica e molecularmente o vírus presente em plantas de <I>Torenia</I> sp. assintomáticas, provenientes de região produtora do Estado de São Paulo. Além disso, uma medida de controle alternativo foi proposta. Verificou-se que o vírus isolado de torênia induziu, em hospedeiras experimentais, sintomas semelhantes aos causados por espécies do gênero Potexvirus. Este resultado foi confirmado por RT-PCR, utilizandose oligonucleotídeos específicos para <i>potexvirus</i>. Testes sorológicos, bem como análises das seqüências obtidas e filogenéticas foram fundamentais para a identificação do <i>Alternanthera mosaic virus</i> (AltMV), denominado de AltMV-T. Convém salientar que este vírus, assim como os potexvirus, de modo geral, são disseminados na cultura por instrumentos de poda e por contato. Visando um controle eficiente e de baixo custo, extrato foliar de <i>Mirabilis jalapa</i> foi pulverizado em plantas de <i>Chenopodium amaranticolor</i>, antes do corte das folhas com lâmina previamente imersa em inóculo viral. Verificou-se uma inibição da infecção causada pelo AltMV-T em 83%. Esse resultado viabiliza a utilização de extrato foliar de <I>M. jalapa</I>, antes dos procedimentos de desbaste das plantas, minimizando-se a disseminação do vírus pela cultura.