Fig. 3. MoSPAB1 promotes rice susceptibility by activating Bsr-d1.

a Pathogenicity of Guy11, the ΔMoSPAB1 mutant, and the complemented strain in rice leaves using punch inoculation. Photos (left panel) were taken and lesion lengths (right panel) were calculated. n = 9, 9, 7, and 9, respectively, showed in a. b H₂O₂ levels in rice after M. oryzae inoculation. n = 3 biologically independent samples. c Bsr-d1 expression levels in rice leaves after spraying inoculation. RNA samples were extracted from TP309 leaves 12, 24, 36, 48 and 96 hpi with Guy11, the ΔMospab1 mutant, and the complemented strain, individually. Mock was inoculated without M. oryzae. n = 3 biologically independent samples. d Rice blast susceptibility with heterologous MoSPAB1^ΔSP expression. n = 9, 10, and 12, respectively, showed in d. e Bsr-d1 and Perox3 expression levels in rice plants with heterologous MoSPAB1^ΔSP expression. n = 3 biologically independent samples. f Simultaneous binding of MoSPAB1^ΔSP and MYBS1 to the Bsr-d1 promoter in a DNA pull-down assay. A 1689-bp biotin-labeled Bsr-d1 promoter was co-incubated with His-MoSPAB1^ΔSP and GST-MYBS1. Increasing concentrations (1×, 5×) of MoSPAB1^ΔSP was respectively incubated with a fixed concentration of GST-MYBS1 (left panel), or vice versa (right panel). Intensity of the band was quantified and the ratio was shown below the lane. Similar results are obtained from two independent biological experiments. g Effects of MoSPAB1^ΔSP and MYBS1 on Bsr-d1:LUC reporter expression in a dual-luciferase reporter assay using rice protoplasts. n = 3 biologically independent samples. In (a, b, c, d, e–g) Data are mean ± SD. Different letters indicate significant differences at P < 0.05 (one-way ANOVA followed by two-sided least significant difference (LSD) test for multiple-comparisons). P-values are shown in the Source Data file. Source data are provided as a Source Data file.