Echinochloa phyllopogon is a major weed of rice in California. This species has evolved resistance to multiple herbicides within a water seeded, continuously-flooded, monocropped and heavily herbicide-dependent rice system. Use of enzyme inhibitors, enzyme activity assays, and metabolomics suggested resistance to multiple herbicides resulted from enhanced herbicide metabolism via inducible P450s, GSTs, and glycosyl transferases. Resistant plants also exhibit insensitivity to ethylene stimulation by quinclorac, enhanced detoxification of cyanide from ethylene biosynthesis, and mitigate paraquat-induced photooxidative stress. Candidate gene transcription assays suggest resistance could relate to adaptive stress tolerance. Use of synergistic herbicide combinations, different herbicide mechanisms of action, alternation of dry and water seeding methods, and use of stale seedbed techniques in combination with no-till are resistance mitigation attempts. New diversification options are needed to sustain a system compromised by herbicide-resistance evolution to multiple herbicides in major weeds.

Multifactorial herbicide resistance in <i>Echinochloa phyllopogon</i> of California rice fields

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Multifactorial herbicide resistance in Echinochloa phyllopogon of California rice fields