Figure 7.

Effects of Phi treatment on gene expression, protein accumulation, and phosphorylation of MPK4 in response to Hpa. A, MPK4 expression. B, Accumulation and phosphorylation state of MPK4 protein. Plants were treated and inoculated as described in the legend of Figure 3. Samples were harvested at 0, 8, and 10 hpi. Two aliquots of leaf tissues were used for the quantification of MPK4 transcripts by qRT-PCR as for PR1 transcripts in the legend of Figure 4. Another aliquot of leaf tissues was used for protein extraction and SDS-PAGE. A polyclonal α-MPK4 antibody was used for the immunodetection of MPK4 protein. α-Phospho-p44/42 ERK antibody was used to check the phosphorylation state of MPK4. A leaf protein extract of the mpk4 mutant was used as a negative control for MPK4. The experiment was repeated three times with similar results. The asterisk indicates data that are significantly different between Phi and MES treatments (Mann-Whitney test; P < 0.05).