FIGURE 6.

Weakened wheat defense response in TaTypA knock-down plants challenged by avirulent Pst race CYR23. Wheat leaves previously treated with recombinant BSMV:γ or BSMV:TaTypA were inoculated with race CYR23. (A) Typical leaves were examined at 24, 48 and 120 hpi. The infection sites were observed by epifluorescence. HMC, haustorial mother cell; SV, substomatal vesicle; NC, necrotic cell death; IH, primary hyphae; SH, secondary hyphae. All results were obtained from 50 infection sites. Bar, 20 μm. (B) Necrotic cell death was quantified as the area of autofluorescence. (C) Hyphal lengths are means of the average distance from the junction of the substomatal vesicle to the hyphal tip. (D) Hyphal branch values are means of average numbers of primary hyphae. (E) Expression of TaPR1 was assayed in TaTypA knock-down plants compared to controls. The data were normalized to the wheat TaEF-1a gene. Asterisks indicate a significant differences (P < 0.05) from BSMV:γ using the Tukey’s HSD test.