Light-triggered catalase like nanozyme mitigates frost damage of winter oilseed rape via carbon dot-mediated membrane homeostasis and metabolic reprogramming

Abstract

Winter oilseed rape is a vital industrial crop, primarily cultivated for the production of vegetable oil, biodiesel, and industrial lubricants. Mitigation of frost damage in winter oilseed rape is critical for ensuring stable yields and quality. To address this challenge, we engineered a multifunctional light-triggered catalase like nanozyme (denoted as YTzymes) integrating catalase-like activity with yellow-light emission, specifically designed to counteract frost-induced adversity in winter oilseed rape. The dual-action mechanism of YTzymes underpins its efficacy:1) Intrinsic catalase-like activity directly scavenges excess reactive oxygen species (ROS) that accumulate rapidly in plant cells under frost stress, thereby alleviating oxidative damage to crop cells; 2) Yellow light emission from the nanozyme triggers targeted metabolic reprogramming, modulating linoleic acid metabolism (a key component of membrane lipids) to maintain integrity of cell membranes, while simultaneously enhancing the tricarboxylic acid (TCA) cycle flux to boost energy supply and redox homeostasis. Foliar application of 600 mg/L YTzymes solution significantly promoted frost recovery in winter oilseed rape. Compared to untreated frost-stressed plants, the dry weight of shoots and roots in the nanozyme-treated group increased by 21.56% and 11.15%, respectively, accompanied by improved cell membrane integrity. Meanwhile, the reduction of Ca 2 + concentration and increment of K + concentration could further reduce the osmotic pressure of the cell, reducing the cell dehydration in freezing conditions. This light-triggered nanozyme approach offers an efficient solution to mitigate frost damage, thereby contributing to the development of sustainable crop production under changing climate conditions.