The circadian clock of diverse crops can be re-entrained postharvest
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Postharvest circadian rhythms enhance pest resistance and phytochemical cycling
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Defense glucosinolates accumulate with circadian rhythmicity in Arabidopsis
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An anticancer phytochemical, 4MSO, accumulates cyclically in re-entrained cabbage
Summary
The modular design of plants enables individual plant organs to manifest autonomous functions [1] and continue aspects of metabolism, such as respiration, even after separation from the parent plant [2]. Therefore, we hypothesized that harvested vegetables and fruits may retain capacity to perceive and respond to external stimuli. For example, the fitness advantage of plant circadian clock function is recognized [3, 4]; however, whether the clock continues to influence postharvest physiology is unclear. Here we demonstrate that the circadian clock of postharvest cabbage (Brassica oleracea) is entrainable by light-dark cycles and results in enhanced herbivore resistance. In addition, entrainment of Arabidopsis plants and postharvest cabbage causes cyclical accumulation of metabolites that function in plant defense; in edible crops, these metabolites also have potent anticancer properties [5]. Finally, we show that the phenomena of postharvest entrainment and enhanced herbivore resistance are widespread among diverse crops. Therefore, sustained clock entrainment of postharvest crops may be a simple mechanism to promote pest resistance and nutritional value of plant-derived food.