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An emerging soybean disease observed in Cuba was investigated in view of the possibility that a phytoplasma could be involved in its aetiology. Thirty-five soybean plants showing symptoms of stunting, chlorosis, crinkle and aborted seed pods were collected in Las Tunas and Holguin provinces during 2013, and analysed by nested-PCR with primers targeting the 16S ribosomal DNA (16S rDNA). Phytoplasmas were detected in 83% of symptomatic soybean plants. Conventional and virtual RFLP analyses of 16S rDNA sequences revealed the presence of strains of 'Candidatus Phytoplasma asteris' (16SrI group). Phytoplasmas belonging to ribosomal subgroup 16SrI-B and two putative new ribosomal subgroups 16SrI-W and 16SrI-Y were identified. Phylogenetic analysis corroborated the RFLP analyses, in which the Cuban strains formed a clade with representative sequences of the 16SrI group. 16SrI-B was the most prevalent subgroup (45% of positive samples) and mixed infections of different subgroups were observed (10% of the positive samples). The partial 16S rDNA sequences of three strains showed 99% nucleotide identity to several GenBank sequences of group 16SrI phytoplasmas, including a phytoplasma associated with a soybean disease in Brazil. This is the first report of a phytoplasma belonging to the 16SrI subgroup occurring in soybean in Cuba. [ABSTRACT FROM AUTHOR]

We report the complete nucleotide sequences of geminiviruses of the genus Begomovirus infecting soybean ( Glycine max) in central Brazil. Samples obtained from soybean plants collected at Santo Antonio de Goiás, Goiás State, showing typical symptoms of viral infection, were analyzed. Infection was confirmed by PCR-based amplification of a DNA-A fragment with universal begomovirus primers. Total DNA from infected plants was then subjected to rolling-circle amplification (RCA), and 2.6-kb molecules were cloned into plasmid vectors. Sequencing of the three DNA-A and two DNA-B clones thus obtained confirmed infection by three distinct begomoviruses: bean golden mosaic virus, Sida micrantha mosaic virus and okra mottle virus, the last of which was reported recently to be a novel virus infecting okra plants in Brazil. Begomovirus infection of soybean plants has been reported sporadically in Brazil and has generally not been considered to be of economic relevance. [ABSTRACT FROM AUTHOR]

Beach bean ( Canavalia rosea) plants showing mosaic symptoms were found at Massaguaçú beach, Caraguatatuba, Brazil. A potyvirus was found to be responsible for the symptoms, based on transmission assays and electron microscopy. A positive reaction in ELISA was obtained against cowpea aphid-borne mosaic (CABMV) antisera. Viral identity was confirmed by RT-PCR using specific primers to amplify part of the NIb and the entire CP coding region of the genome and the 3′NTR. Comparison of the amplified sequences with that of CABMV showed a nucleotide sequence identity of 97% for the CP coding region. Thus, the potyvirus from beach bean should be considered a CABMV isolate, referred to as CABMV-Cr. [ABSTRACT FROM AUTHOR]

Lettuce mottle virus (LeMoV) and dandelion yellow mosaic virus (DaYMV) infect lettuce in South America and Europe, respectively. LeMoV and DaYMV possess isometric particles, occur at low concentrations in plants and have narrow host ranges. Partial genome sequences of both viruses were obtained using purified viral preparations and universal primers for members of the family Sequiviridae. DaYMV and LeMoV sequences were analyzed and showed identity with other members of the family. Universal primers that detect both viruses and specific primers for LeMoV and DaYMV were designed and used in RT-PCR-based diagnostic assays. These results provide the first molecular data on the LeMoV and DaYMV genomes and suggest that LeMoV is a member of the genus Sequivirus, probably distinct from DaYMV. [ABSTRACT FROM AUTHOR]

Summary. Tomato-infecting begomoviruses have been reported throughout Brazil since the introduction of the B biotype of Bemisia tabaci. Here, we report a large scale survey on the distribution and genetic diversity of tomato-infecting begomoviruses. Tomato samples with typical begomovirus symptoms were collected in seven different states, comprising the major tomato growing areas of the country. Viruses were detected by polymerase chain reaction (PCR) using universal primers for the genus Begomovirus. PCR-amplified fragments were cloned and sequenced. Based on sequence comparisons and phylogenetic analyses, at least seven previously undescribed species of begomoviruses were found. Four of the new viruses were found exclusively in the Southeastern states, two exclusively in the Northeastern states, and one was found in both regions. Sequence comparisons reveal strong evidence of recombination among the Brazilian begomoviruses. Together, the results indicate the existence of a high degree of pre-existing genetic diversity among tomato-infecting begomoviruses in Brazil and suggest that these viruses have emerged after being transferred from natural hosts to tomatoes, due to the introduction into Brazil of a novel polyfagous biotype of the whitefly vector. [ABSTRACT FROM AUTHOR]