Lígia Maria Lembo Duarte

Effect of Potato virus X on total phenol and alkaloid contents in Datura stramonium leaves

The present paper reports results of the effect of Potato virus X (PVX) on the contents of total phenols and alkaloids in leaves of Datura stramonium. A significant decrease in the contents of phenols and alkaloids was observed in leaves inoculated with PVX (X-I). However, there was an increase in the percentage of phenols in leaves rubbed with phosphate buffer (C1-I) and in leaves from the nodes immediately above, possibly induced by mechanical injury. Gas chromatography/mass spectroscopy revealed amounts of scopolamine in samples submitted to all treatments, except X-I, in which the amount of this alkaloid was low. High amounts of an unidentified compound (molecular ion m/z 302 and a prominent peak at m/z 129) were noted in extracts from leaves X-I, C1-I and leaves from the nodes immediately above the leaves inoculated with PVX. It is suggested that the synthesis and accumulation of the unidentified compound is a result of stress from mechanical injury and virus inoculation.

A new Badnavirus species detected in Bougainvillea in Brazil

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.

Phylogenetic analysis of Tomato mosaic virus from Hemerocallis sp. and Impatiens hawkeri

The culture and commercialization of ornamental plants have considerably increased in the last years. To supply the commercial demand, several Hemerocallis and Impatiens varieties have been bred for appreciated qualities such as flowers with a diversity of shapes and colors. With the aim of characterizing the tobamovirus isolated from Hemerocallis sp. (tobamo-H) and Impatiens hawkeri (tobamo-I) from the USA and Sao Paulo, respectively, as well as to establish phylogenetic relationships between them and other Tobamovirus species, the viruses were submitted to RNA extraction, RT-PCR amplification, coat-protein gene sequencing and phylogenetic analyses. Comparison of tobamovirus homologous sequences yielded values superior to 98.5% of identity with Tomato mosaic virus (ToMV) isolates at the nucleotide level. In relation to tobamo-H, 100% of identity with ToMV from tomatoes from Australia and Peru was found. Based on maximum likelihood (ML) analysis it was suggested that tobamo-H and tobamo-I share a common ancestor with ToMV, Tobacco mosaic virus, Odontoglossum ringspot virus and Pepper mild mottle virus. The tree topology reconstructed under ML methodology shows a monophyletic group, supported by 100% of bootstrap, consisting of various ToMV isolates from different hosts, including some ornamentals, from different geographical locations. The results indicate that Hemerocallis sp. and I. hawkeri are infected by ToMV. This is the first report of the occurrence of this virus in ornamental species in Brazil.

Biological and molecular characterization of a putative new potexvirus infecting Senna occidentalis

In this work, we report the complete genome sequence of, production of polyclonal antibodies against, and development of biological assays for a putative new potexvirus, named senna mosaic virus (SenMV), found infecting Senna occidentalis in the state of São Paulo, Brazil. The complete genome sequence of SenMV comprises 6775 nucleotides excluding the poly(A) tail. The genome organization is similar to those of other potexviruses, with five open reading frames coding for RNA-dependent RNA polymerase (RdRp), the triple gene block (TGB 1, 2, and 3) proteins, and coat protein (CP). The virus was transmitted to S. occidentalis by mechanical inoculation and trimming scissors, but not by seeds.

First report of Tomato chlorotic spot virus on Mirabilis jalapa

Mosaic symptoms in Mirabilis jalapa plants from a public garden in the city of São Paulo, Brazil, were associated with the presence of Tomato chlorotic spot virus (TCSV-Mir-BR07). TCSV-Mir-BR07 was mechanically transmitted to healthy M. jalapa plants. Phylogenetic analysis revealed a monophyletic group formed by South American TCSV isolates separate to those from Central and North America. This is the first report of natural TCSV infection in M. jalapa.

Canna paniculata as natural host of canna yellow streak virus in Brazil

Canna yellow streak virus (CaYSV) was identified on Canna paniculata with foliar mosaic symptoms from Piracicaba municipality (São Paulo state, Brazil) by transmission electron microscopy, biological, serological and molecular assays. Pairwise analyses of nucleotide and amino acid sequences (potyvirus cylindrical inclusion region) with homologous sequences revealed the highest identity (88.6 and 97.8%) with CaYSV. This is the first detection of CaYSV in Brazil.

First report of Turnip mosaic virus on Tropaeolum majus in Brazil.

Tropaeolum majus (Tropaeolaceae), popularly known as garden nasturtium and often confused with Nasturtium officinale (Brassicaceae), is widely cultivated in southern and southeastern regions of Brazil as ornamental, medicinal and food plant. T. majus plants from Sao Paulo state showing symptoms of mosaic, blistering and leaf distortion were subjected to biological, serological and molecular tests for virus diagnosis. Inoculations on Chenopodium species induced local lesions and reproduced the original symptoms on T. majus. Naturally and experimentally infected T. majus reacted positively to an antiserum raised against a potyvirus group in DAS-ELISA and against a Turnip mosaic virus (TuMV) antiserum in indirect ELISA. Total RNA was extracted from infected T. majus leaf, and RT-PCR carried out using primers designed on the sequence of part of the cytoplasmic inclusion region of the potyviral genome (Ha et al., 2008), produced a fragment ca. 700 bp in size The fragment was directly sequenced (GenBank accession No. KJ635891) and its sequence (TuMV-TR02) was similar to that of TuMV isolates NDJ (AB093616) and Al (AB093598) with 78.8 and 92.1% nucleotide identity, respectively. Phylogenetic trees constructed with maximum parsimony, maximum likelihood and neighbor-joining algorithms using the PAUP program were similar. The TuMV-TR02 isolate formed a monophyletic group with isolates from Italy belonging to the basal-B group proposed by Oshima et al. (2002). This is the first report of TuMV on garden nasturtium in Brazil.

Hyacinth mosaic virus infecting Hyacinthus sp. plants in Brazil

Hyacinthus orientalis (Asparagaceae) is an ornamental plant that has been recently introduced into the Brazilian market from Europe. A plant showing leaf mottling was acquired at a flower market in the city of São Paulo and subjected to transmission, serological (ELISA) and molecular (RT-PCR, sequencing and phylogenetic analysis) detection assays to identify a possible causal agent of viral nature for the symptoms. The plant was ELISA positive with a potyvirus group antiserum. A fragment of the coat protein (CP) coding region was RT-PCR amplified and directly sequenced. The deduced amino acid sequence of the CP shares the highest identity (96%) with Hyacinth mosaic virus (HyaMV). The Brazilian hyacinth potyvirus isolate formed a monophyletic group with HyaMV isolates from Asparagaceae and Amaryllidaceae species. This is the first detection of HyaMV in Brazil, and infection is likely to be widespread because hyacinths multiply through bulbs, which accumulate viruses and facilitate their dissemination.

A new Potyvirus species in Cotyledon orbiculata in mixed infection with a Nucleorhabdovirus.

Several species and varieties of the family Crassulaceae have been introduced and cultivated for ornamental as well as medicinal purposes in Brazil, more prominently Cotyledon orbiculata (pig’s ear). This work reports the identification and characterization of viruses associated with foliar mosaic and distortion of C. orbiculata from the succulent plant collection of the garden of the University of Sao Paulo, Brazil. In situ analyses revealed enveloped bacilliform particles in the perinuclear space of infected C. orbiculata cells, and cytoplasmic cylindrical inclusions, typical of the family Potyviridae. Viruses were mechanically transmitted and separated by differential indicator hosts and aphid transmission (Myzus persicae). Chenopodium amaranticolor and Datura stramonium served as differential hosts for the potyvirus and the bacilliform virus, respectively. Positive serological reactions were obtained when leaf extracts from naturally infected C. orbiculata and experimental hosts were exposed to an antiserum to Sonchus yellow net virus (genus Nucleorhabdovirus). Identification of the potyvirus by RT-PCR, cloning into pGEM-T vector and sequencing generated a 1,752 nt fragment corresponding to part of the nuclear inclusion protein b (NIb), the complete coat protein (CP) and the untranslated region (UTR). Amino acid identities below 80% were observed, indicating that the potyvirus of C. orbiculata may be a new species for which the name Cotyledon virus Y (CotVY) is suggested.