Monomethylhydrazine content is determined by altitude in Gyromitra antarctica: Implications for safe consumption

Several species of the genus Gyromitra-commonly known as "false morels"-are traditionally consumed in different parts of the world, despite their potential toxicity due to the presence of monomethylhydrazine, a volatile compound. In some taxa, monomethylhydrazine content has been linked to environmental factors such as elevation, potentially influencing toxicity levels. In southern South America, ethnomycological records indicate that Gyromitra species are collected and consumed by indigenous communities. However, their taxonomy and toxicological profile remain poorly understood. In this study, we examined the phylogenetic identity and hydrazine content of Gyromitra specimens collected across a Patagonian elevation gradient. Molecular analyses based on nuclear internal transcribed spacer, large subunit, and elongation factor-1 alpha sequences confirmed the identity of all specimens as G. antarctica. Hydrazine content was quantified in 82 fresh samples collected between 300 and 800 m above sea level, revealing a significant negative correlation between elevation and toxin concentration (ρ = -0.79, P < 0.001). Two boiling treatments -10 min without water exchange, and 2 × 5 min with water exchange-reduced hydrazine levels by 97% and 94%, respectively. However, residual toxins were detected in the boiling water of both treatments. These findings provide new insights into the taxonomy and elevation-dependent toxicity of Gyromitra in the Southern Hemisphere. They also underscore the risks associated with the consumption of wild false morels and highlight the importance of informed and adequate culinary practices to reduce toxicity.