Caracterização de um isolado de Bean rugose mosaic virus e busca por fontes de resistência em Phaseolus vulgaris
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2017-03-31
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Universidade Federal de Goiás
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Abstract: In 2013, common bean plants of the cultivar Pérola were found in an experimental field belonging to Embrapa Arroz e Feijão Lat. 16 ° 28 '00 "(S); Long. 49 ° 17 '00 "(W); (GO) presenting leaf distortion, mosaic and blistering. The sample analysis by electron microscopy detected the presence of typical Comovirus genus viral particles, thus, the identification of the virus species through sequencing became essential and the search for control alternatives, due to the damage potential of Bean rugose mosaic virus (BRMV) to bean production fields. Therefore, the present work had as objectives: (1) the molecular characterization of BRMV-GO, an isolate from common bean and (2) the search for bean accessions resistant to this viral species. For germplasm selection, 172 accessions were analyzed by means of mechanical inoculation and visualization of symptoms at 5, 21 and 30 days after inoculation. The range of hosts was analyzed by inoculation of 15 typical indicator species. Soya plants (Cv. Savana, Cv. Cristalina, Cv. Doko and Cv. Conquista) and pea (Cv. Mikado and Cv. Triofin) were also analyzed for reactions to BRMV-GO. Leaves of the infected plants were used for detection of BRMV-GO through RT-PCR. Of the 172 analyzed accessions, 168 behaved as susceptible, 3 accessions: BGF0011750 (cv. Mulatinho), BGF0000880 (cv. Rico 23) and BGF0001083 (cv Rico 23) reacted to BRMV-GO with vein and petioles necrosis followed by death; 1 access, BGF0003174 cv. IPA5047, showed a hypersensitivity reaction. The two species of the indicator Chenopodium amaranticolor and C. quinoa reacted with local necrotic lesions and no systemic infection confirmed by RT-PCR. Soybean plants reacted as susceptible and all pea plants showed tip burning. For molecular characterization, complete genome sequencing was performed by Sanger method using the primer walking strategy, the 5 'and 3' ends were obtained by RACE method. Genome sizes were 5906 nucleotides with a 1856 amino acid polyprotein for RNA 1 and 3688 nucleotides with a polypeptide of 1096 amino acids for RNA 2. The nucleotide identity between BRMV-GO and BRMV-Paraná isolates was 92.7% for RNA 1 and 90.5% for RNA 2. The highest percentage of identity obtained by amino acids sequence
alignment of the polymerase (RdRp) and the capsid protein (CP) was 63% (RdRp) and 66% (CPs) with Bean pod mottle virus (BPMV), however, the ICTV delimits 80% (RdRp) and 75% (CP) identity to be part of the Comovirus genus, however, these results agree with the results obtained in another work with a Paraná isolate, corroborating that BRMV is a distinct species among this genus. Phylogenetic analysis of regions RdRp and CPs showed that BRMV-GO and BRMV-Paraná do not have significant differences and revealed higher indexes of identity with BPMV, both for RNA 1 and RNA 2. The complete sequences of RNA 1 and RNA 2 were deposited on Genbank under accession numbers KY622124, KY622125, respectively.
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CÂNDIDA, D. V. Caracterização de um isolado de Bean rugose mosaic virus e busca por fontes de resistência em Phaseolus vulgaris. 2017. 76 f. Tese (Doutorado em Agronomia) - Universidade Federal de Goiás, Goiânia,
2017.