Development of a promoter-luciferase-based high-throughput system to monitor jasmonate-mediated defense gene expression

Abstract

Defense gene expression systems of higher plants responsible for protection against pathogen attack are predominantly regulated by salicylic acid (SA)and jasmonic acid (JA)-mediated pathways, and control the expression of many downstream defense response genes. To monitor the regulated gene expression of SA-mediated signaling pathways, we previously described an assay system based on the bioluminescence of seedlings transformed with a promoter-luciferase fusion gene. Here, to develop a system suitable for JA-mediated gene expression monitoring, we compared the expression patterns of Arabidopsis gene promoters obtained from the plant defensin 1.2 (PDF1.2) and vegetative storage protein 1 (VSP1) genes in response to treatment with chemicals. Although both promoters responded well to treatment with JA in 3-week-old plants, only the VSP1 promoter exhibited marked and prolonged luciferase expression in response to JA treatment in 6-dayold seedlings. The use of transgenic Arabidopsis seedlings harboring the VSP1-luciferase reporter gene construct enables multiwell plates to be used for conducting high-throughput assays for the screening of chemicals that are involved in JAmediated signaling pathways in Arabidopsis.