Table 1.

Screening for inhibitors of Dickeya zeae MS2 type III secretion system (T3SS) by Multifunctional Microplate Reader.

ID	Compound (0.2 mM)	Chemical structures	Average MFI ± SDa	DMSO%b
Phytohormone
IAA	Indole-3-acetic acid		11,608.67 ± 137.42	96.58
MeJA	Methyl Jasmonate		12,568.33 ± 248.82	104.56
SA	Salicylic acid		4,962.33 ± 77.69	41.28
GA3	Gibberellin A3		11,248.33 ± 178.20	93.58
t-Z	Trans-zeatin		11,491.33 ± 436.43	95.60
Other compounds
HA	Hydrocinnamic acid		8,073.00 ± 87.43	67.16
PHBA	p-Hydroxybenzoic acid		8,868.00 ± 62.07	73.77
OCA	o-Coumaric acid		11,441.33 ± 170.00	95.18
PCA	p-Coumaric acid		4,783.00 ± 168.59	39.79
2-CCA	2-Chlorocinnamic acid		11,108.33 ± 85.23	92.41
CA	Cinnamic alcohol		6,198.00 ± 355.33	51.56
AS	Acetosyringone		17,213.00 ± 217.44	143.20

Average MFI ± SD of dimethyl sulfoxide (DMSO) was 12,020.33 ± 226.40.

^aDickeya zeae MS2 cells carrying the green fluorescent protein (GFP) reporter pPhrpA were grown in LS5 supplemented with 0.2 mM compounds for 14 h. GFP mean fluorescence intensity (MFI) of bacterial cells was determined by Multifunctional Microplate Reader. Three replicates were used in each compound and three independent experiments were performed.

^bDMSO% represents the relative promoter activity of hrpA, calculated according to the formula: DMSO% = 100 × MFI_compound/MFI_DMSO.