An Arabidopsis thaliana mutant with virus-inducible phenotype.

The role of host factors in plant viral diseases is not well understood. To study this important aspect of plant-pathogen interaction, we identified an Arabidopsis thaliana mutant, designated vid1 (virus-inducible dwarf), with altered responses to viral infection. Specifically, vid1 resembled the wild-type plants when healthy but developed a severely dwarfed phenotype with a loss of apical dominance following infection by a tobamovirus. Genetic segregation showed that the vid1 phenotype is caused by a recessive mutation in a single gene. Since systemic viral infection is thought to interfere with the host plant intercellular transport, we propose that the vid1 mutation affects this transport process. Combination of the mutation and viral infection may disrupt transport of developmental regulators, such as hormones, causing formation of the vid1 phenotype. Indeed, the effect of vid1 mutation was repressed by exogenous application of a plant hormone auxin. Potentially, the vid1 mutant will help characterize the mechanism of virus-plant interaction and formation of plant viral disease symptoms. Copyright 1998 Academic Press.