In Brazil, at least eight begomoviruses including Tomato rugose mosaic virus (ToRMV) and Tomato yellow spot virus (ToYSV) infect tomatoes. ToYSV symptoms in tomato and Nicotiana benthamiana appear earlier and are more severe compared to those of ToRMV. We investigated the role of several factors in this differential adaptation. To analyze infection kinetics, a single leaf was inoculated and subsequently detached after different periods of time. Viral DNA accumulation was quantified in plants, viral replication was analyzed in protoplasts, and tissue tropism was determined by in situ hybridization. Results indicate that ToYSV establishes a systemic infection and reaches a higher concentration earlier than ToRMV in both hosts. ToRMV negatively interferes with ToYSV during the initial stages of infection, but once systemic infection is established this interference ceases. In N. benthamiana, ToYSV invades the mesophyll, while ToRMV is phloem-restricted. During dual infection in this host, ToYSV releases ToRMV from the phloem.

BackgroundBegomoviruses are dicot-infecting, whitefly-transmitted viruses with a genome comprised of one or two molecules of circular, single-stranded DNA. In Brazil, tomato-infecting begomoviruses have emerged as serious pathogens since the introduction of a new biotype of the insect vector in the mid-1990’s. Tomato rugose mosaic virus (ToRMV) and Tomato severe rugose virus (ToSRV) are often found in tomato fields. The complete sequence of the DNA-B components of ToSRV and ToRMV show an identity of 98.2%. Additionally, the high nucleotide identity (96.2%) between their common regions indicates that these two viruses may share the same DNA-B.MethodsTomato seedlings were biolistically inoculated with ToSRV (DNA-A and DNA-B) and ToRMV (DNA-A and DNA-B) infectious clones in every possible combination of single or mixed infection. Symptom expression was evaluated for up to 35 days post-inoculation (dpi). DNA was extracted at 28 dpi and the presence of each viral genomic component was examined by rolling circle amplification (RCA) followed by digestion, as well as by quantitative, real-time PCR. Sequence comparisons, recombination and phylogenetic analyzes were performed using EMBOSS needle, RDP program and maximum likelihood inference, respectively.ResultsSymptoms in tomato plants inoculated with the different combinations of ToRMV and ToSRV DNA-A and DNA-B components consisted of a typical mosaic in all combinations. Pseudorecombinants were formed in all possible combinations. When two DNA-A or two DNA-B components were inoculated simultaneously, the ToRMV components were detected preferentially in relation to the ToSRV components. The combination of minor changes in both the Rep protein and the CR may be involved in the preferential replication of ToRMV components. Recombination and phylogenetic analyzes support the exchange of genetic material between ToRMV and ToSRV.ConclusionsToRMV and ToSRV form viable pseudorecombinants in their natural host (Solanum lycopersicum) and share the same DNA-B. ToRMV DNA components are preferentially replicated over ToSRV components. These results indicate that the emergence of ToRMV involved both recombination and pseudorecombination, further highlighting the importance of these mechanisms in the emergence and adaptation of begomoviruses.

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Introdução: A cirurgia videolaparoscópica é um método cirúrgico minimamente invasivo do abdômen e seus órgãos internos, realizada através de uma câmera ligada através da parede abdominal por meio de pinças pelo cirurgião. As cirurgias mais comuns por laparoscopia são: bariátrica, ginecológica, tratamento de hérnias abdominais, entre outras. Objetivo: Mostrar as vantagens e desvantagens da cirurgia videolaparoscópica e estudar os avanços em relação a novas técnicas utilizadas na medicina em relação a cirurgia. Método: Trata-se de uma pesquisa descritiva do tipo revisão integrativa de literatura, que busca relatar os pontos positivos e negativos da cirurgia videolaparoscópica em relação a laparatomia. A pesquisa foi realizada por meio de bases de dados PubMed MEDLINE, Scientific Electronic Library Online (Scielo), Cochrane Library, Google Scholar, LILACS e Google acadêmico, durante os meses de julho e agosto de 2021. Dessa maneira, totalizaram-se 29 produções científicas para revisão integrativa da literatura. Resultados: Tendo em vista os procedimentos cirúrgicos envolvendo a laparoscopia e a laparotomia, é possível perceber maiores benefícios no primeiro procedimento, como uma alta hospitalar mais rápida pela incisão minimamente invasiva que esta permite. Conclusão: A videolaparoscopia é um procedimento moderno e menos invasivo, usado como alternativa para a laparotomia, possuindo vantagens como um menor tempo cirúrgico, redução de complicações e morbimortalidade e um melhor resultado estético da cicatrização, mas também desvantagens como lesão nos órgãos e vasos, herniação ou diminuição na capacidade residual pulmonar. Com isso, a laparotomia é mais necessária em pacientes com riscos cardíacos e pulmonares.