Identification and molecular characterization of Carnation mottle virus Brazilian isolates from carnation

Abstract

Carnation mottle virus (CarMV), associated with carnation plants showing or not symptoms, was identified by host range, serology and molecular analysis of the coat protein gene. Seven samples were assayed by biological and serological tests. Two of them, one from São Paulo and another from Minas Gerais states, Brazil, which presented higher absorbance values in DAS-ELISA, were selected for molecular studies. Foliar samples were submitted to total RNA extraction, RT-PCR with specific primers, and amplicons obtained were sequenced. Phylogenetic analyses were carried out using the PAUP program after determining the nucleotide substitution model. The identity percentages between Brazilian sequences were 99%. When sequences of CP carnation isolates from other countries were compared, the identity ranged from 96-99%. CarMV isolates from São Paulo and Minas Gerais states are the first sequences obtained in Brazil, and analysis showed that they belong to the PK group and showed only two amino acids changes at positions 61 and 260. The virus presents a high genetic stability and it is readily mechanically transmitted from infected to healthy plants. This is the first report of CarMV in Minas Gerais state, of CP nucleotide sequences from Brazilian CarMV isolates, as well as molecular phylogenetic analysis in Brazil.