Expression Profiling during Arabidopsis/Downy Mildew Interaction Reveals a Highly-Expressed Effector That Attenuates Responses to Salicylic Acid
Figure 5
Hpa suppresses PR1 expression induced by SA in infected cells.
(A) Expression pattern of 871 BTH-inducible genes reported by Wang et al. (2006) [48] after inoculation with Hpa Emoy2 and Waco9. The relative expression (in log2 ratios) is colored red for induction and green for repression as illustrated in the fold change color bars. (B) Expression of PR1 in Arabidopsis at 1, 3, and 5 dpi with Hpa Emoy2 and Waco9. The expression level was determined by qRT-PCR using specific primers for PR1 and indicated as relative fold induction compared to water-treated samples (mock). Expression of EF-1α was used to normalize the expression value in each sample. Data are means ± SDs from three biological replicates. (C) GUS staining in three-week-old Arabidopsis leaves containing PR1 promoter fused GUS (PR1::GUS) at 1 and 2 dpi with Hpa Emoy2 and at 6 dpi with Hpa Waco9. Lower images are magnified upper images. Black and red asterisks indicate Hpa-haustoriated and non-haustoriated mesophyll cells, respectively. cs, conidiospore. Scale bars = 40 µm. (D) GUS staining in Hpa-infected PR1::GUS lines 8 hours after treatment with SA (200 µM). The leaves at 4 dpi with Hpa Waco9 or spraying water (mock) were infiltrated with SA or water (mock). Red arrows indicate Hpa-haustoriated cells. Scale bars = 100 µm.