Citrus leaf blotch virus in Cuba: first report and partial molecular characterization

Abstract

Citrus leaf blotch virus (CLBV) infection has been detected in citrus cultivars from several countries including the USA, Spain, Italy, Japan and New Zealand. To investigate whether CLBV is present in Cuba, a survey was conducted in seven commercial citrus fields of the country during 2007-2013. In all, 1940 trees were inspected and samples of two symptomatic and 18 asymptomatic sources were tested by biological indexing and molecular techniques for virus detection. Bark patches from the two symptomatic Nagami and Round kumquat sources induced chlorotic blotching and vein clearing in Dweet tangor, and only for the Round kumquat inoculums, stem pitting in Etrog citron. RT-PCR assays using specific primers to amplify fragments of polymerase (RdRp), movement (MP) and coat protein (CP) genes of CLBVyielded amplicons with the expected sizes using RNA from both sources as a template. Viral RNA was further detected by a non-radioactive dot-blot hybridization assay using a mixture of specific probes derived from a Spanish isolate of CLBV. Sequences from RdRp, MP, and CP amplicons showed identical nucleotide identities for the two Cuban isolates, and higher than 95.9 % with isolates from Spain, New Zealand and the USA.