BENZOTHIADIAZOLE INDUCES DISEASE RESISTANCE IN ARABIDOPSIS BY ACTIVATION OF THE SYSTEMIC ACQUIRED-RESISTANCE SIGNAL-TRANSDUCTION PATHWAY

Benzothiadiazole (BTH) is a novel chemical activator of disease resist ance in tobacco, wheat and other important agricultural plants. In thi s report, it is shown that BTH works by activating SAR in Arabidopsis thaliana. BTH-treated plants were resistant to infection by turnip cri nkle virus, Pseudomonas syringae pv 'tomato' DC3000 and Peronospora pa rasitica. Chemical treatment induced accumulation of mRNAs from the SA R-associated genes, PR-1, PR-2 and PR-5. BTH treatment induced both PR -1 mRNA accumulation and resistance against P. parasitica in the ethyl ene response mutants, etr1 and ein2, and in the methyl jasmonate-insen sitive mutant, jar1, suggesting that BTH action is independent of thes e plant hormones. BTH treatment also induced both PR-1 mRNA accumulati on and P. parasitica resistance in transgenic Arabidopsis plants expre ssing the nahG gene, suggesting that BTH action does not require salic ylic acid accumulation. However, because BTH-treatment failed to induc e either PR-1 mRNA accumulation or P. parasitica resistance in the non inducible immunity mutant, nim1, it appears that BTH activates the SAR signal transduction pathway.