Fig. 3

Very low Si-conditioned powdery mildew resistance requires SA-pathway components EDS1, PAD4 and SID2. a Representative microscopic images showing growth of Gc UCSC1 at 5 dpi on leaves of Col-0 or pad4–1 plants grown in perlite supplemented with 0 mM (−Si) or 1.0 mM (+Si) Si. Fungal structures were stained blue by trypan blue, while production and accumulation of H₂O₂ by the host was visualized as reddish-brown stain (highlighted in the insets) upon reaction with 3,3-diaminobenzidine. Scale bars = 200 μm. b Representative Gc UCSC1-infected leaves of plants from the indicated genotypes grown in perlite supplemented with 0 mM (−Si) or 1.0 mM (+Si) Si. Pictures were taken at 10 dpi. c Quantification of spore production at 10 dpi in plants of the indicated genotypes in (b). d, e Total SA and JA levels in Gc UCSC1-infected leaves of wild-type Col-0 plants grown in perlite supplemented with 0 mM (−Si) or 1.0 mM (+Si) Si. Leaf samples were collected and analyzed at 0, 3 and 5 dpi. Error bar indicates SE based on 4 replicates, and asterisks denote significant difference (Student t-test, *P < 0.05)