Abstract
C6-aldehydes can induce defense genes and induce accumulation of antifungal substances in Arabidopsis. In order to elucidate the signaling pathway induced by C6-aldehydes, we compared the responses of mutants deficient in the phytohormone signaling pathways; i.e. jar1-1, etr1-1, npr1-1, or pad2-1. When compared with the wild type (WT) plant, inductions of the defense genes in response to C6-aldehydes were significantly repressed in jar1-1 and pad2-1, but not in etr1-1 nor in npr1-1. After C6-aldehyde treatment, significant accumulations of camalexin could be observed with WT and npr1-1, but only partial accumulation could be observed with etr1-1, and jar1-1. pad2-1 showed little accumulation of camalexin after the treatment. The treatment could also enhance resistance of etr1-1, jar1-1 and npr1-1 against Botrytis cinerea, but failed to enhance the resistance with pad2-1. Thus, it was suggested that ETR1-, JAR1- and PAD2-dependent signalings were activated by C6-aldehyde treatment, but NPR1-dependent signaling was not.
