Figure 1
Purification and chemical structure of SAGs. (A) SAGs were purified from strawberry leaves by bioassay-guided normal phase (Zorbax-NH2) chromatography by collecting the unique fraction with plant defense inducing activity (arrow) which was later fractioned by (B) Carbopac PA-1 anionic exchange phase chromatography. (C) Bacterial count in leaves of Arabidopsis plants treated with each numbered peak and subsequently inoculated with the pathogen Pseudomonas viridiflava was determined and expressed as logarithm of colony forming units per leaf fresh weight (log CFU/g FW). Water-treated and thereafter inoculated plants are shown as infection control (IC) and non-inoculated plants as Mock treatment (M). (*) Denote statistically significant value using the DGC test (p < 0.05). Experiments were repeated four times with eight plants assayed for each peak. (D) Peak eluted at 6.487 minutes was chemically identified as the trisaccharide (GalNAc-GalNAc-Glc), esterified to a mono-unsaturated 6–12 carbons length fatty acid (R).
