Salicylic acid accumulation in transgenic Brassica rapa transformed with a gene encoding bacterial isochorismate synthase

The accumulation of salicylic acid (SA) in Brassica rapa ssp. oleifera transformed with a bacterial isochorismate synthase (ICS) gene was examined in the old and young leaves of the primary transformants through high performance liquid chromatography analysis. The level of SA and SA glucoside (SAG) in the transformed plants varied between the individual plants but the SA contents of the leaves in all transgenic plants were increased significantly in comparison to the control plants. Increased SA levels were accompanied by increased accumulation of the SAG. This finding suggests that the ICS gene was expressed and functional in inducing SA biosynthesis in B. rapa. The primary transformed plants showed a normal phenotype, but the flowering plants produced less seeds.