ISHS Acta Horticulturae 657: XIX International Symposium on Virus and Virus-like Diseases of Temperate Fruit Crops - Fruit Tree Diseases
IDENTIFICATION OF CITRUS TRISTEZA VIRUS STRAINS IN LOUISIANA AND ALABAMA |
| Authors: | R. Valverde, A. Landry, M. Nesbitt, P. Lotrakul, W. Dozier, R. Ebel |
| Keywords: | PCR, dsRNA, ELISA, monoclonal antibody, Citrus spp., coat protein, Satsumas |
| DOI: | 10.17660/ActaHortic.2004.657.92 |
| Abstract:
Samples from citrus trees (sweet orange, Satsuma, Meyer lemon, kumquat, and grape fruit) from dooryard and commercial orchards in South Louisiana and South Alabama were collected and tested for the presence of Citrus tristeza virus (CTV) using the enzyme-linked inmunosorbent assay (ELISA) with a broad spectrum antiserum. Positive samples were tested again by ELISA using monoclonal antiserum MCA-13, which reacts with decline inducing (DI) strains of CTV. In Louisiana, 159 samples were positive of 881 tested. Of those 159 positive trees, 28 were also positive with antiserum MCA-13. With the exception of one sweet orange, all other DI isolates were found in Meyer lemon. Similarly in Alabama 17 of 75 trees tested were positive and most DI isolates were detected on Meyer lemon. Four DI isolates were selected for reverse transcriptase-polymerase chain reaction (RT-PCR) using primers that amplified the entire coat protein gene. RT-PCR products were sequenced and compared with corresponding sequences of CTV strains in the GenBank. Scions from these four isolates were grafted, using the micro-budding method, to sour orange, Mexican lime, Madame Vinous sweet orange, and Duncan grapefruit. Symptoms were recorded during a year period. Only stunting and chlorosis symptoms were observed in all grafted citrus species. There was no evidence of stem pitting on indicator hosts. Sequence comparisons of the coat protein gene suggest that DI isolates found in Louisiana are similar to CTV strains reported in Florida. | |
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