Comparative infection progress analysis of Lettuce big-vein virus and Mirafiori lettuce virus in lettuce crops by developed molecular diagnosis techniques

Navarro, J. A.. Botella. F., Maruhenda, A.. Sastre. P.. Sanchez-Pina, M. A.. and Pallas, V. 2004. Comparative infection progress, analysis of Lettuce big-vein virus and Mirafiori lettuce vints in lettuce crops by developed molecular diagnosis techniques. Phytopathology 94:470-477. Nonisotopic molecular clot blot hybridization technique and multiplex reverse transcription-polymerase chain reaction assay for the specific detection of lettuce big-vein virus (LBVV) and Mirafiori lettuce virus (MiLV) in lettuce tissue were developed. Both procedures were suitable for the specific detection of both Viruses in it range of naturally infected lettuce plants front various Spanish production areas and seven different cultivars. The study of the distribution of both viruses in the plant revealed that the hi.-hest concentration of LBVV and MiLV Occurred in roots and old leaves. respectively. LBVV infection progress in a lettuce production area was faster than that observed for MiLV. In spite of different rates of virus infection progress, Most lettuce plants became infected with both viruses about 100 clays posttransplant. The appearance of both viruses in lettuce crops was preceded by a peak in the concentration of resting spores and zoosporangia of the fungus vector Olpidium brassicae in lettuce roots. brassicue in lettuce roots.