Fig. 5

Exogenous NAD(P)⁺-induced local immune responses and biological induction of SAR in several PTI mutants. a Exogenous NAD(P)⁺-induced local PR1 expression in the wild-type (WT), bak1-5, bkk1, bak1-5 bkk1, fls2 efr, and bik1 plants. Leaves of 4-week-old soil-grown plants were infiltrated with 0.2 mm NAD⁺, 0.4 mm NADP⁺ or H₂O. The infiltrated leaves were collected 20 hr later. Total RNA was extracted and subjected to qPCR analysis. Expression levels of PR1 were normalized against the constitutively expressed UBQ5. Data represent the mean ± SD of three biological replicates. Asterisks denote significant differences between the induction in the mutants and that in the wild type (*p < 0.05, **p < 0.01, ***p < 0.001; two-way ANOVA with Sidak’s test). Upper line: induction by NADP⁺; lower line: induction by NAD⁺. b Exogenous NAD(P)⁺-induced local resistance in the wild-type, bak1-5, bkk1, bak1-5 bkk1, fls2 efr, and bik1 plants. Leaves of 4-week-old soil-grown plants were infiltrated with 0.2 mm NAD⁺, 0.4 mm NADP⁺ or H₂O. Five hr later, the infiltrated leaves were inoculated with a Psm suspension (OD₆₀₀ = 0.001). Three d later, eight leaves were collected to examine the growth of the pathogen. Data represent the mean ± SD of eight biological replicates. Asterisks denote significant differences between the induction in the mutants and that in the wild type (*p < 0.05, **p < 0.01; two-way ANOVA with Sidak’s test). Upper line: induction by NADP⁺; lower line: induction by NAD⁺. c Expression of PR1 in the systemic leaves of the wild-type, bak1-5, bkk1, bak1-5 bkk1, fls2 efr, and bik1 plants with or without SAR induction. Three lower leaves on each 4-week-old soil-grown plant were infiltrated with 10 mm MgCl₂ or a Psm suspension (OD₆₀₀ = 0.002). Two d later, systemic leaves were collected for PR1 expression analysis by qPCR. Data represent the mean ± SD of three biological replicates. Asterisks denote significant differences between the induction in the mutants and that in the wild type (***p < 0.001; two-way ANOVA with Sidak’s test). d Biological induction of SAR in the wild-type, bak1-5, bkk1, bak1-5 bkk1, fls2 efr, and bik1 plants. Three lower leaves on each 4-week-old soil-grown plant were infiltrated with 10 mm MgCl₂ or a Psm suspension (OD₆₀₀ = 0.002). Two d later, two systemic leaves were challenge-inoculated with Psm (OD₆₀₀ = 0.001). Three d later, eight leaves were collected to examine the growth of the pathogen. Data represent the mean ± SD of eight biological replicates. Asterisks denote significant differences between the induction in the mutants and that in the wild type (***p < 0.001; two-way ANOVA with Sidak’s test). e, f Overlaps among the genes that were up- or downregulated f in the systemic leaves of the wild-type, bak1-5, and lecrk-VI.2-2 plants. Plants were treated as in c. Total RNA extracted from the systemic tissues was subjected to microarray analysis. Genes with an absolute fold change ≥ 2 and a q value ≤ 0.05 were compared with obtain overlapped genes among the wild-type, bak1-5, and lecrk-VI.2-2 plants