Fig. 2.

Effects of increased and decreased endogenous TAA [ascorbic acid (AS) and dehydroascorbic acid (DHA)] on Turnip mosaic virus (TuMV) infection in turnip (Brassica rapa subsp. rapa) and Arabidopsis thaliana. (A) TAA content in the second true leaves of turnip cultivar CR Mochibana treated with water (mock) or 10mM l-galactose. The l-galactose solution was brushed onto turnip plants daily for 5 d before inoculation. (B) Number of TuMV strain TuR1-YFP infection sites on the second true leaves of CR Mochibana treated with water (mock) or 10mM l-galactose. (C) TAA content in A. thaliana ecotype Columbia (Col-0) and the T-DNA insertion mutant of the ascorbate oxidase (ao) gene (At5g21100). (D) Viral accumulation of TuMV strain TuR1-YFP in non-inoculated upper leaves of wild-type Col-0 and the ao mutant. Viral levels were determined by measuring the absorbance at 405nm on a microtiter plate in an ELISA. (E) TAA content in Col-0 and the vtc1 mutant. (F) Mean number of infection sites on four inoculated leaves of Col-0 and the vtc1 mutant 5 d after inoculation with TuMV strain TuR1-YFP. Viral inoculation was carried out after treatment with 40h darkness. Error bars indicate the SE for 3–6 biological replicates. Asterisks represent significant differences determined by Student’s t-test (*P≤0.05, **P≤0.01).