Fig. 4
Complementation of PH-1-Δosp24-1 and promoter analyses under different conditions. A Complementation of the PH-1-Δosp24-1 mutant strain with the osp24 gene residing within the TSI locus 1 (PH-1-Δosp24-osp24-1) restores full virulence. Photographs were taken at 14 dpi. Marked spikelets in each floral spike indicate the inoculation points. Bar graph shows no differences in the number of infected spikelets between PH-1 and PH-1-Δosp24-1-osp24 whilst the mutant strain shows reduced virulence. Visibly diseased spikelets were counted after 14 dpi and include the point of inoculation. Mock indicates plants inoculated with water. Error bars indicate SD. B Confocal images of strains expressing GFP under the control of different promoters. Strain expressing constitutive GFP (PtrpC-GFP-TtrpC) displayed fluorescence when Fg was grown in TB3 liquid medium as well as during wheat spike infection (lemma). Expression of GFP under the control of the trichodiene synthase promoter (PTri5-GFP-TtrpC) or an effector promoter (PFgeffector1-FgEffector1-GFP-TtrpC) only occurs during infection. The PH-1 strain was used as control to set confocal conditions. Images were taken at 3 dpi. C Relative expression of GFP for strains expressing GFP under the control of the promoters PTri5, PFgeffector1 and PtrpC during growth in TB3 and wheat spike infection. Data represent mean of three replicates. Error bars denote the 95% confidence interval. Statistically significant differences between PtrpC-GFP-TtrpC with PTri5-GFP-TtrpC and PFgeffector1-Fgeffector1-GFP-TtrpC were calculated using one-way ANOVA followed by Tukey post-hoc test (P < 0.05)