Genetic Screening System for Identifying Rice Immune Regulators Using Bioluminescence-Based Defense Gene Reporter

Overview

This solution offers a high-throughput genetic screening platform designed to identify key regulators of rice pattern-triggered immunity (PTI). Built on a transgenic rice line carrying a luciferase reporter driven by the chitin-responsive defense gene promoter OsPBZ1, the system enables researchers to visualize and quantify defense gene activation in real time using bioluminescence. When treated with chitin—a microbe-associated molecular pattern (MAMP)—the reporter produces a strong luminescent signal, whereas untreated plants show negligible activity. By applying this reporter line within an ethyl methanesulfonate (EMS)-mutagenized population, mutants with altered defense signaling can be rapidly identified and subsequently evaluated for resistance to rice blast disease.

The platform addresses a critical need in agricultural biotechnology: the efficient discovery of immune regulators that can be leveraged to develop disease-resistant rice varieties. By coupling a sensitive luminescent readout with pathogen resistance phenotyping, the system streamlines the path from gene discovery to functional characterization.

Technical specifications

Core components:

• pOsPBZ1::LUC transgenic rice line expressing luciferase under the control of the chitin-inducible defense gene promoter OsPBZ1
• EMS-mutagenized M2 seedling population derived from the transgenic reporter line
• Chitin treatment protocol (12-hour immersion) to trigger defense gene expression and bioluminescence
• Bioluminescence imaging and quantification to identify mutants with altered OsPBZ1 activation
• Downstream rice blast resistance assays to confirm functional relevance of candidate mutants
• Map-based cloning pipeline for identifying causal mutations in immunity-altered mutants

Key features:

• Sensitive luminescent reporter enables non-destructive, real-time monitoring of PTI signaling
• Scalable genetic screen suitable for large mutant populations
• Direct linkage between altered defense gene expression and pathogen resistance phenotypes
• Applicable to functional characterization of novel immune regulators in rice

Technology readiness level

The system has been experimentally validated: pOsPBZ1::LUC activity is clearly detected in transgenic rice seedling leaves following chitin treatment, while water-treated controls show negligible signal, confirming the specificity and reliability of the reporter. The platform is currently positioned for expanded use as a genetic screening tool, with future validation focused on screening EMS-mutagenized M2 populations for altered bioluminescence, confirming rice blast resistance phenotypes in selected mutants, and employing map-based cloning to identify and characterize key components of rice PTI signaling regulation.