Luciferase-mediated assay to detect the PAMP-triggered gene expression in transgenic <i>Nicotiana benthamiana</i>

Luciferase is one of the bioluminescence-producing agents, which was widely used as a reporter enzyme for constructing bioassay systems to study gene expression with high accuracy and within a broad dynamic spectrum. Perception of pathogen associated molecular patterns (PAMPs) in plants often lead to significant transcriptional changes. The transcriptional changes of defense-related genes are often used as a marker to assay PAMP-triggered plant immune response. In this study, we showed that the marker gene <i>CYP71D20</i> was rapidly activated in <i>Nicotiana benthamiana</i> upon treatment with the bacterial PAMP flg22 and the Phytophthora elicitin INF1. In addition, we generated transgenic <i>N. benthamiana</i> using the luciferase as a reporter gene to analyze <i>CYP71D20</i> gene expression upon PAMP treatment. The transgenic line carrying the luciferase gene driven by <i>CYP71D20</i> promoter was treated with the bacterial PAMP flg22 or Phytophthora elicitin INF1. Transcriptional activation of <i>CYP71D20</i> was measured by monitoring the luciferase activity. The results showed that the LUC activity was increased after treatment with different PAMPs, indicating that the <i>CYP71D20</i>-promotor luciferase assay can be used to study the PAMP-triggered gene expression in <i>N. benthamiana</i>.