Arabidopsis mutants that suppress the phenotype induced by transgene-mediated expression of cauliflower mosaic virus (CaMV) gene VI are less susceptible to CaMV-infection and show reduced ethylene sensitivity.

Protein P6 is the main symptom determinant of cauliflower mosaic virus (CaMV), and transgene-mediated expression in Arabidopsis induces a symptom-like phenotype in the absence of infection. Seeds of a P6-transgenic line, A7, were mutagenized by gamma-irradiation and M2 seedlings were screened for mutants that suppressed the phenotype of chlorosis and stunting. We identified four mutants that were larger and less chlorotic than the A7 parent but which contained an intact and transcriptionally active transgene.

Mutations that delay flowering in Arabidopsis de-couple symptom response from cauliflower mosaic virus accumulation during infection.

summary The development of disease symptoms in plants infected with a compatible virus involves complex signalling interactions between host and viral gene products. Photoperiod is an important influence on the transition from vegetative growth to flowering. Symptoms in wild-type Arabidopsis plants grown under long days were much less severe than in plants grown under short days, although under long days, the levels of replicating virus were 1.