Decrement of catalase mRNA level after salicylic acid treatment

Using the barley catalase cDNA as a probe, the effects of salicylic acid (SA) on catalase activity and gene expression have bene studied. The data indicated that higher than 3.0 mmol/I, SA inhibited catalase activity to a large extent and Northern blot analysis demonstrated that the decrease in catalase activity coincided with a decrease in its mRNA level. The important role of SA in plant systemic acquired resistance (SAR) and its possible mechanism are discussed.