The effect of growth temperature, on big-vein symptom and serological detection of Mirafiori lettuce virus and Lettuce big-vein virus in lettuce

From lettuce (Lactuca sativa) leaves with big-vein symptoms, two viruses associated with lettuce big-vein, Mirafiori lettuce virus (MiLV) and Lettuce big-vein virus (LBW), were isolated. To make clear which virus is really associated with big-vein symptoms expression, the effect of the growth temperature for lettuce, on the serological detection of the two viruses and symptom expression was analyzed. At 27 deg C, LBW was detected in the leaves, but neither the big-vein symptoms nor MiLV were observed. When the growth temperature was decreased to 18 deg C, big-vein symptoms appeared and MiLV was detected in the leaves.