Proteomic Approaches to Study the Mode of Action of Safeners for Chloroacetamide Herbicides in Triticum Tauschii

Abstract

Safener cloquintocet-mexyl completely protected the shoot from herbicide injury, while the root was protected to about 70% of control. Thirty-one safener-induced and 15 herbicide-regulated proteins were identified in three different tissues of Triticum tauschii seedlings with proteomic methods. These proteins were classified into 3 major categories based on protein expression patterns and further categorized into functional groups. The largest functional category of safener-responsive proteins belongs to xenobiotic detoxification and metabolism (Phases I, II and IV). The major category of herbicide regulated-proteins belongs to stress and defense response, including peroxidase, pathogenesis-related proteins. Results indicate that safeners protect Triticum tauschii seedlings from herbicide injury by coordinately inducing enzymes and proteins involved in an entire herbicide detoxification pathway (Phase I-Phase IV) mainly in the coleoptile and root and therefore protect new leaves from herbicide injury. These results also suggest that herbicides and safeners may trigger different signaling pathways involving different plant hormones; the two signaling pathways may antagonize each other leading to rapid herbicide metabolism, detoxification, and prevention of herbicide toxicity.