Symptoms of Cauliflower Mosaic Virus Infection in Arabidopsis thaliana and Turnip

The type of symptoms of cauliflower mosaic virus (CaMV) infection observed in Arabidopsis thaliana and turnip depend on host species and viral isolate. Inflorescences of infected A. thaliana plants were chlorotic, often in sectors that also involved axillary shoots, cauline leaves, and siliques. Infection also affected silique and seed morphology and, in some shoots, the ability of seeds to germinate and the sensitivity of seeds to bleach. Isolate NY8153 and isolates derived from CM4-184 caused stunting of rosette leaves, while isolate CM4-184 did not. CaMV nucleic acid was detected in seed coats but not in embryos of seeds from infected plants. The symptoms on turnip leaves (chlorotic spotting, chlorotic mottling, fine vein clearing, necrotic spotting, coarse vein clearing, stunting, rugosity, senescence, and pale greenness) depended on the age of the leaf at infection and on the viral isolate used. Symptoms occurred in left-right and tip-to-base sectors. The observations suggest that viral infection, to cause symptoms, acts primarily on differentiating cells.