Studies on Antagonistic Interaction between Environmental Stress Response and Systemic Acquired Resistance in Arabidopsis

Abstract

Systemic acquired resistance (SAR) is one of plant defense systems. To investigate the influences of environmental stress on SAR induction, we analyzed the effects of abscisic acid (ABA) on SAR. In this study, we used 1,2-benzisothiazole-3(2H)-one 1,1-dioxide (BIT) and benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) for SAR induction, which activate upstream and downstream of SA in SAR signaling pathway, respectively. ABA treatment suppressed SAR induced either by BIT or BTH in Arabidopsis. The environmental stress such as salinity, drought and ABA suppressed the expression of PR-1 gene. On the other hand, the expression of some of ABA-biosynthesis or ABA-responsive genes were down-regulated by treatment with BIT or BTH. These data suggest that there should be some crosstalks between the ABA-mediated signaling and SAR signaling.