Evolution of herbicide resistance through co-option of an ethylene-associated nitrilase

In Echinochloa crus-galli, cyhalofop-butyl resistance evolved over decades and is driven mainly by co-option of EcNIT4A2, with a D317G substitution boosting detoxification.

• Why it matters: The work addresses how pre-existing functions are repurposed to create new adaptive traits on contemporary timescales, using herbicide resistance as a rapid-evolution model.
• What they did: Genetic mapping, transcriptomics, and transgenic tests identified EcNIT4A2 as the major resistance determinant; D317G increased herbicide-detoxifying activity, and simulations suggest improved substrate access.
• The result: A promoter structural variant strongly increased EcNIT4A2 expression, showing coding and regulatory changes together can optimize a conserved metabolic function under intense herbicide selection.

AI summary of the abstract · may contain errors · not medical advice · read the paper.