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ARS Home » Research » Publications at this Location » Publication #237688
Title: First Report of Tomato Chlorosis Virus in Tomato in Costa Rica

Author
item CASTRO, R - SAN JOSE COSTA RICA
item HERNANDEZ, E - SAN JOSE COSTA RICA
item MORA, F - SAN JOSE COSTA RICA
item RAMIREZ, P - SAN JOSE COSTA RICA
item Hammond, Rosemarie

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2009
Publication Date: 9/1/2009
Citation: Castro, R.M., Hernandez, E., Mora, F., Ramirez, P., Hammond, R. 2009. First Report of Tomato Chlorosis Virus in Tomato in Costa Rica. Plant Disease. 93:970.

Interpretive Summary: In early 2007, severe yellowing and chlorosis were observed in field-grown tomatoes in Costa Rica. Symptoms resembled those caused by the whitefly-transmitted criniviruses, and large populations of whiteflies were observed in the fields and on symptom-bearing plants. Studies were conducted by an ARS scientist in Beltsville, Maryland and collaborators in Costa Rica to identify the causal agent(s) of the disease. Results of molecular analyses revealed that the crinivirus, Tomato chlorosis virus (ToCV), was associated with the disease in tomatoes. This is the first report of ToCV in Costa Rica. This information has been communicated to growers in Costa Rica and is being used to assess the incidence of the virus and the economic impact on tomato production. The results impact U.S. agriculture as the greenhouse whitefly which transmits ToCV is emerging as a serious threat to tomato production in North America.

Technical Abstract: In early 2007, severe yellowing and chlorosis symptoms were observed in field-grown and greenhouse tomato (Solanum lycopersicum L.) plants in Costa Rica. The symptoms resembled those of the genus Crinivirus (family Closteroviridae) and large populations of whiteflies were observed in the fields and on symptomatic plants, including the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). Total RNA was extracted from silica gel-dried tomato leaf tissue of 47 representative samples (all were from symptomatic plants) using TRI Reagent (Molecular Research Inc., Cincinnati, OH). Reverse transcription-polymerase chain reactions (RT-PCR) reactions were performed separately with each of the three primer sets using the Titan One-Tube RT-PCR kit (Roche Diagnostics Corp., Chicago IL). The specific primers used for detection of the criniviruses Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV), were primer pair ToCV-p22-F (5’-ATGGATCTCACTGGTTGCTTGC-3’) and ToCV-p22-R (5’-TTATATATCACTCCCAAAGAAA-3’), specific for the p22 gene of ToCV and primer pair TICV-CP-F (5’-ATGAGGTCTTTCACAGTGGA-3’) and TICV-CP-R (5’-TGTCACCTTCTTTTCTTCAAA-3’), specific for the coat protein gene of TICV(1), and the degenerate primer pair MA59 (TT(A/G)GA(T/G)TT(C/T)GGTACTAC(A/T)TTCAGTTRGAKTTYGGTACTACWTTCAG) and MA60 (AA(A/T)GTACC(T/G)CCACCAAA(A/G)TCGTAAWGTACCKCCACCAAARTCGT), amplifying the HSP70h gene of ToCV (2). Amplified DNA fragments (582 bp) were obtained from 9 samples using the ToCV-p22 specific primers and were cloned into the pCRII TOPO cloning vector (Invitrogen, Carlsbad, CA). Nucleotide sequence analysis of all purified PCR products verified their identity as variants of ToCV, sharing 99.5–100% sequence identity among themselves; one representative sequence was deposited at GenBank. The isolates shared 96% to 98% sequence identity with previously reported ToCV p22 sequences from Florida, Spain, Greece, and the United States. No PCR products were obtained using either the TiCV-specific primers, the degenerate primers, nor from healthy tomato tissue. The ToCV-positive samples were collected from a region around Cartago, Costa Rica, in the Central Valley. To our knowledge, this is the first report of ToCV in Costa Rica. The economic impact on tomato has not yet been determined. Studies are underway to determine the incidence of ToCV in Costa Rica field-grown and greenhouse tomatoes.