Figure 2. Powdery mildew resistance by impairment of PMR4 is conserved between Arabidopsis and tomato.

(A and B), Leaf of T2 plant 4–5 (A) carrying a RNAi::SlPMR4 silencing construct (+) and of T2 plant 4–4 (B) without silencing construct (−) at the age of 5 weeks and 8 days post O. neolycopersici inoculation. (C), Relative SlPMR4 transcript levels in untransformed Moneymaker (MM) plants and progeny of 3 independent T1 plants transformed with a silencing construct specifically targeting SlPMR4 (family 2, 3 and 4). T2 progenies harbouring a silencing construct (RNAi::SlPMR4 (+)) showed significantly lower transcript levels compared to untransformed Moneymaker plants and progenies not harbouring a silencing construct (−) as indicated by asterisks. (D), Quantification of fungal growth of lines mentioned in (C). SlPMR4 silenced plants show significantly less fungal growth compared to non-silenced plants as indicated by asterisks, demonstrating that SlPMR4 is a functional ortholog of PMR4. (E and F), Relative plant height and stem diameter of 12 week old plants respectively. A slight reduction (although significant as indicated by asterisks) in plant height was observed for progenies carrying a RNAi::SlPMR4 construct of families 2 and 3, but not 4. Stem diameters were somewhat lower among T1 progenies of all 3 families, but differences were not statistically significant. For C, D, E and F, data indicate the mean of 3 or more biological replicates with error bars representing the standard error. Number of asterisks indicate degree of significance (**p<0.01; ***p<0.001).