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First Report of Cotton Leafroll Dwarf Virus Infecting Cacao ( Theobroma cacao ) Trees in Brazil
2022; American Phytopathological Society; Volume: 107; Issue: 4 Linguagem: Inglês
10.1094/pdis-07-22-1570-pdn
ISSN1943-7692
AutoresRoberto Ramos‐Sobrinho, Mayra Machado de Medeiros Ferro, Gaus Silvestre de Andrade Lima, Tatsuya Nagata,
Tópico(s)Plant Disease Resistance and Genetics
ResumoHomePlant DiseaseVol. 107, No. 4First Report of Cotton Leafroll Dwarf Virus Infecting Cacao (Theobroma cacao) Trees in Brazil PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Cotton Leafroll Dwarf Virus Infecting Cacao (Theobroma cacao) Trees in BrazilR. Ramos-Sobrinho, M. M. M. Ferro, G. S. A. Lima, and T. NagataR. Ramos-Sobrinhohttps://orcid.org/0000-0002-7280-3916Setor de Fitossanidade, Campus de Engenharias e Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL 57100-000, Brazil, M. M. M. FerroSetor de Fitossanidade, Campus de Engenharias e Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL 57100-000, Brazil, G. S. A. LimaSetor de Fitossanidade, Campus de Engenharias e Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL 57100-000, Brazil, and T. Nagata†Corresponding author: T. Nagata; E-mail Address: [email protected]https://orcid.org/0000-0002-7114-017XDepartamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, BrazilAffiliationsAuthors and Affiliations R. Ramos-Sobrinho1 M. M. M. Ferro1 G. S. A. Lima1 T. Nagata2 † 1Setor de Fitossanidade, Campus de Engenharias e Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL 57100-000, Brazil 2Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil Published Online:29 Mar 2023https://doi.org/10.1094/PDIS-07-22-1570-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleCotton leafroll dwarf virus (CLRDV; genus Polerovirus, family Solemoviridae) is often reported affecting cotton plants (Gossypium spp., family Malvaceae) and several weed species (Ramos-Sobrinho et al. 2021; Sedhain et al. 2021). During a 2022 survey, cacao (Theobroma cacao L.) trees exhibiting virus-like symptoms such as leaf mosaic, vein clearing, and yellow spot were observed in the south part of the state of Bahia, northeastern Brazil. Leaf samples were randomly collected from symptomatic plants (n = 30) in an affected area of ∼30 ha. Total RNA from pooled cacao samples was subjected to Illumina HiSeq 2,500 sequencing as previously described (Keith et al. 2021), and partial sequences of CLRDV and other virus-specific sequence contigs were de novo assembled according to Ramos-Sobrinho et al. (2021). To further investigate the presence of CLRDV in cacao leaves, total RNA was individually extracted using a modified silica protocol (Rott and Jelkmann 2001) and used as template for cDNA synthesis with random hexamers using the SuperScript IV First-Strand Synthesis System (Invitrogen, CA, U.S.A.) following the manufacturer's protocol. Detection of CLRDV was carried out by reverse transcription (RT)-PCR with the primers PL4F and o3-R, which amplify the open reading frame 3 (ORF3) encoding the capsid protein (Corrêa et al. 2005). Expected size amplicons (∼0.6 kb) were observed from 16 out of 30 symptomatic plants, indicating ∼53% of the trees were infected by CLRDV. Since 14 symptomatic plants tested negative for CLRDV, the symptoms observed here could also be caused by other viral groups or abiotic stress. To confirm the detection of CLRDV, the first half (∼3.5 kb) of the viral genome was amplified from two representative samples using the primers P20F and P22R (Avelar et al. 2020). The RT-PCR products were gel-purified using the Wizard SV Gel and PCR Clean-Up System (Promega, WI, U.S.A.) and Sanger sequenced. The RNA Illumina sequencing from pooled samples (n = 30) yielded 34,610,572 million trimmed reads. Two contigs of 868 and 839 nucleotides (nt) and sharing high nt identity with CLRDV isolates were assembled from 6,903 to 10,271 reads, at a coverage depth of 795 and 1,224×, respectively. Together, these contigs represent ∼29% of the complete viral genome and included part of the 5′-untraslated region, ORF0, and the second half of ORF1-ORF2. Additional CLRDV-like contigs were observed across the viral genome, but they were not considered for further analyses due to the poor sequence quality. The Illumina- and Sanger-derived ORF0 and partial ORF1-ORF2 sequences shared >97% nt identity, suggesting they were congruent. Pairwise sequence comparisons for ORF0, encoding the gene silencing suppressor P0, indicated the cacao-associated isolates shared 99.7 and 99.2% nt and amino acid (aa) identity with each other, respectively. The ORF0 nt sequences showed 91.9 to 93.8 and 90.7 to 93.6% identity, while the aa sequences shared 85.8 to 88.5 and 86.2 to 90.0% similarity, with CLRDV isolates previously reported in South America and the United States, respectively. The ∼3.5-kb nt sequences of cacao-infecting CLRDV isolates shared 92.9 to 95.8% identity with CLRDV genomes deposited in GenBank. The Bayesian phylogenetic tree reconstructed based on ORF0 nt sequences showed the new sequences were more closely related to CLRDV-atypical isolates (GenBank nos. KF359946, KF359947, KF906260, and KF906261). Together, these results suggest the new ORF0 sequences belong to CLRDV and were deposited in GenBank (ON954058 to ON954059). To our knowledge, this is the first report of CLRDV infecting cacao plants, expanding the range of malvaceous hosts of this polerovirus. CLRDV is largely known for causing yield losses in cotton, but additional studies are needed to determine whether CLRDV infection harms cacao production.The author(s) declare no conflict of interest.References:Avelar, S., et al. 2020. Plant Dis. 104:780. https://doi.org/10.1094/PDIS-06-19-1316-RELink, ISI, Google ScholarCorrêa, R. L., et al. 2005. Arch. Virol. 150:1357. https://doi.org/10.1007/s00705-004-0475-8Crossref, ISI, Google ScholarKeith, C. V., et al. 2021. Front. Agron. 3:774863. https://doi.org/10.3389/fagro.2021.774863Crossref, Google ScholarRamos-Sobrinho, R., et al. 2021. Viruses 13:2230. https://doi.org/10.3390/v13112230Crossref, ISI, Google ScholarRott, M. E., and Jelkmann, W. 2001. Eur. J. Plant Pathol. 107:411. https://doi.org/10.1023/a:1011264400482Crossref, ISI, Google ScholarSedhain, N. P., et al. 2021. Crop Prot. 144:105604. https://doi.org/10.1016/j.cropro.2021.105604Crossref, ISI, Google ScholarFunding: Funding was provided by a research fellowship from the National Council for Scientific and Technological Development (CNPq).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 107, No. 4 April 2023SubscribeISSN:0191-2917e-ISSN:1943-7692 Download Cover Image Metrics Article History Issue Date: 27 Apr 2023Published: 29 Mar 2023First Look: 23 Sep 2022Accepted: 21 Sep 2022 Page: 1251 Information© 2023 The American Phytopathological SocietyFundingNational Council for Scientific and Technological DevelopmentKeywordsetiologypathogen detectiontropical plantsviruses and viroidsThe author(s) declare no conflict of interest.PDF download
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