Figure 2: Functional VdIsc1 or PsIsc1 is required for full V. dahliae virulence.
(a) Disease symptoms on cotton plants were scored at 15 dpi with the indicated strains. The disease grade is depicted in Supplementary Fig. 3. The total number of infected plants is indicated above each column (**P<0.01; t-test). V991 represents the WT V. dahliae isolate; Δ1-12 (V991ΔVdIsc1-12) and Δ1-18 (V991ΔVdIsc1-18) represent two strains in which VdIsc1 was deleted; Δ1-12VdIsc1, Δ1-12VdIsc1A3, Δ1-12PsIsc1 and Δ1-12PsIsc1A3 represent, respectively, Δ1-12 complemented with VdIsc1, with a VdIsc1 mutant encoding three key amino acid substitutions (D26A, K100A and C133A), with PsIsc1 and with a PsIsc1 mutant encoding comparable substitutions (D25A, K90A and C124A; Supplementary Fig. 2). All complementing constructs used the Aspergillus nidulans trpC promoter. (b) Free SA and SAG levels in cotton roots at 14 dpi. (c) Relative levels of cotton PR1 transcripts measured using qRT–PCR at 12 hpi. Expression was normalized against the constitutively expressed cotton gene Histone3. In b and c, the data represent the mean±s.d.; **P<0.01 (Dunnett’s test) between WT and each transgenic line. (d) Disease symptoms of the Arabidopsis WT and NahG-transformed plants. The disease grades are described in the Methods. The total number of infected plants is shown above each column (**P<0.01; t-test).
