Table 1. Elicitation of SIS by P. syringae, COR, and MeJA
Infecting strain or chemical treatment in lower leaves Dose Host plant Sample size, n Enhanced (+) or diminished (-) Psm growth, log cfu/cm2
Psm ES4326 108 cfu/ml WT 122 (+) 0.69 ± 0.07***
Psm ES4326 (avrRpt2) 108 cfu/ml WT 120 (-) 0.45 ± 0.07***
Pst DC3000 108 cfu/ml WT 120 (+) 0.62 ± 0.14***
Pst DC3000 (avrRpt2) 108 cfu/ml WT 126 (-) 0.45 ± 0.13*
Psm ES4326 cfa6::Kmr 108 cfu/ml WT 123 (+) 0.15 ± 0.07 (ns)
Psm ES4326 cfa6::Kmr (avrRpt2) 108 cfu/ml WT 120 (-) 1.12 ± 0.08***
Psm ES4326 108 cfu/ml coi1-1 64 (+) 0.22 ± 0.19 (ns)
Psm ES4326 (avrRpt2) 108 cfu/ml coi1-1 47 (-) 0.42 ± 0.18*
Psm ES4326 108 cfu/ml npr1-1 36 (+) 0.49 ± 0.14*
Psm ES4326 108 cfu/ml nahG 62 (+) 0.12 ± 0.13 (ns)
COR 10 μM WT 96 (+) 0.41 ± 0.09*
COR 1 μM WT 96 (+) 0.57 ± 0.14**
COR 10-1 μM WT 95 (+) 0.58 ± 0.10***
COR 10-2 μM WT 96 (+) 0.81 ± 0.14***
COR 10-3 μM WT 94 (+) 0.40 ± 0.10**
COR 10-4 μM WT 95 (+) 0.13 ± 0.12 (ns)
MeJA 103 μM WT 72 (+) 0.53 ± 0.12**
MeJA 102 μM WT 72 (+) 0.62 ± 0.14***
MeJA 10 μM WT 72 (+) 0.74 ± 0.11***
MeJA 1 μM WT 71 (+) 0.53 ± 0.11**
MeJA 10-1 μM WT 72 (+) 0.51 ± 0.14**
MeJA 10-2 μM WT 72 (+) 0.24 ± 0.12 (ns)
CMA 1 μM WT 84 (-) 0.22 ± 0.13 (ns)
CFA 1 μM WT 87 (+) 0.06 ± 0.12 (ns)
  • Dose refers to the density of the bacterial suspension or the molarity of the solution that was infiltrated into Arabidopsis leaves to prime defense signaling (see Materials and Methods).

  • Enhanced or diminished growth of a secondary infection of Psm ES4326 in previously primed plants (e.g. with Psm ES4326 cfa6::Kmr) compared with plants primed with 10mM MgSO4. All experiments consisted of at least three independent trials. Data presented represent pooled values from all trials and no treatment × trial interaction was significant. (+) indicates plants exhibiting SIS; (-) indicates plants exhibiting SAR; *, P < 0.05; **, P < 0.01; ***, P < 0.001 (ANOVA with Bonferroni correction). ns, not significant.