Researchers at Leibniz University Hannover have identified a key gene pair in barley that drives the production of gramine, a toxic alkaloid found in one of the world’s most widely cultivated grains. The discovery appears in the science journal Science.
Gramine serves as a chemical defense, deterring herbivorous insects and grazing animals while also suppressing the growth of neighboring plants. Although scientists have pursued this line of inquiry for years, the exact gene responsible for gramine synthesis remained elusive until now.
Genetic analysis revealed a two-gene cluster in barley that governs the biosynthesis process in the grain: HvNMT and HvAMIS. It is the second gene in this pair that was found to trigger toxin formation in the kernels.
Lead researcher Dr. John D’Auria commented that AMIS is an oxidase enzyme performing an unusual latent oxidative rearrangement of tryptophan. This finding prompts a reevaluation of previous biosynthetic models and opens new avenues for understanding how barley builds gramine.
Scientist teams suggest that with this breakthrough, it may be possible to synthesize pure gramine in controlled settings and to develop toxin-free, genetically modified barley varieties tailored for applications in the medical sector.
In related work, earlier studies have highlighted that a significant portion of the U.S. population is exposed to a toxin that has not been extensively studied, underscoring the importance of continued research into plant-derived compounds and their impacts across different sectors. The new findings emphasize how precise genetic insights can guide safer crop development and potential medical applications, while also informing risk assessments and regulatory considerations for toxin production in grains (Science).”