UC Riverside

A formidable challenge in the genomic era is the assignment of structure and function to unknown genes in model organisms. Forward chemical genetics seeks to discover and characterize pathways through the identification of novel phenotypes induced by organic small molecules and subsequent isolation of their target gene(s). Downstream

genetic and biochemical strategies to dissect the action of bioactive molecules are often hampered by weak target-ligand interactions, low target abundance, genetic factors, and synthetic inaccessibility of analogs. We present a synthetic scaffold that simultaneously permits fluorescence detection and photoaffinity labeling (diazirine) in a combinatorial library of thousands of drug-like small molecules synthesized through click chemistry. Using this library, we identified several bioactives that alter seedling growth of the model plant Arabidopsis thaliana and generated candidate ethyl methanesulfonate-induced resistant mutants for downstream simple sequence length polymorphism marker-assisted mapping and single nucleotide polymorphism identification by Illumina next-generation DNA sequencing. Our proof-of-principle study will facilitate target identification of novel bioactives and accelerate chemical genetics discoveries.