Plant-derived natural compounds hold significant potential for crop protection. To fully harness these resources, it is imperative to gain a comprehensive understanding of the genetic background of crops. This knowledge is crucial for the effective optimization and regulation of biosynthetic pathways within plants, thereby enabling the modulation of plant responses to environmental challenges. Alkaloids represent one of the most diverse classes of chemical compounds, prevalent throughout the plant kingdom and serving various functions. Notably, these functions include protective properties and toxic side effects. The toxicity of alkaloids influences plant interactions with herbivores, pathogens, and other organisms, contributing to a continuous co-evolutionary arms race. For instance, insects have developed a range of strategies—such as physiological adaptations, excretion systems, enzymatic detoxification, bacterial symbiosis, and sequestration—to tolerate or detoxify these compounds, which in turn drives further evolution of plant defensive metabolites. Gramine is a tryptophan-derived alkaloid found in various plants, such as barley and lupins, which provides protection against herbivorous insects, as well as fungal and bacterial infections. To assess its abundance and distribution across plant species and tissues for both food safety and research purposes, robust and cost-effective chromatography techniques are required. Consequently, a novel RP-UPLC-FLD method was developed and validated to detect gramine and its precursors. This analytical capability, combined with barley pan-genomic data, enabled more extensive investigations into gramine biosynthesis, particularly in identifying the candidate gene responsible for previously unresolved steps in the pathway, specifically the conversion of tryptophan into AMI. The analysis led to the identification of a gene encoding cytochrome P450 monooxygenase CYP76M57, subsequently named AMI synthase (AMIS).
Sara Leite Dias (Wed,) studied this question.