Enhancement of health-promoting and plant-protecting secondary metabolites by postharvest conditioning with hormetic doses of abiotic stresses

我们的长期目标是开发采收后调节技术，以保持新鲜水果和蔬菜的质量，并使用适合采收后阶段应用的激效或有益剂量的非生物胁迫，增强促进健康和保护植物的次生代谢物。考虑到植物产生次生代谢物作为对抗压力的武器，有可能通过将植物暴露在控制剂量的压力源中，很好地调整反应，以实现增强所需植物化学物质和产品可接受性之间的平衡。我们在短期和中期的工作将集中在了解应激源与新鲜农产品次生代谢物产生之间的联系，以及了解应激诱导的代谢途径的改变。下一步，研究将涉及：(1)确定在选定的新鲜农产品中有效诱导或增强目标（或期望的）次生代谢物的促生非生物胁迫；(2)表征所选择的致热应力产生的信号成分及其在应力组织中的合成能力；(3)胁迫下作物产生所需植物化学物质途径的初级代谢物和次级代谢物及其组合的分析；(4)阐明应激组织中信号组分、合成能力状态与次生代谢产物之间的关系；(5)评价原发性和继发性代谢途径的改变。研究将用胡萝卜根、西兰花和番茄果实进行。从本研究中获得的知识将为开发采后调节方案提供工具，通过知情选择激效胁迫或组合胁迫来实现所需次生代谢物的增强生产。富含植物化学物质的新鲜果蔬被认为是一类新的功能性食品。保存具有增强健康效益和抗病特性的新鲜作物不仅有助于生鲜农产品行业减少采后损失，而且有助于确保人口更健康。

Our long-term goal is to develop post-harvest conditioning technologies to preserve the quality of fresh fruits and vegetables with enhancement in health-promoting and plant-protecting secondary metabolites using hormetic or beneficial doses of abiotic stresses that are suitable for application in the postharvest phase. Given that plants produce secondary metabolites as weapons to combat stresses, it is possible that the response can well be tuned to achieve a balance between enhancement of desirable phytochemicals and acceptability of the produce by exposing them to controlled doses of the stressors. Our efforts in the short- to medium-term will be focused on gaining an understanding of the connections between hormetic stressors and secondary metabolite production in fresh produce, and an understanding of the stress-induced alterations in the metabolic pathways. Going forward, the research would involve: (1) the identification of hormetic abiotic stresses that are effective in inducing or enhancing targeted (or desired) secondary metabolites in selected fresh produce; (2) the characterization of the selected hormetic stresses for their generation of signal components and the consequent synthetic capacity in the stressed tissues; (3) the profiling of primary metabolites, and secondary metabolites of the pathways that produce the desired phytochemicals in the crops exposed to the stresses and their combinations; (4) the elucidation of the relationships between signal components, synthetic capacity status, and secondary metabolites in the stressed tissues; and (5) the evaluation of alterations in the primary, and the secondary metabolic pathways. Studies will be performed with carrot root, broccoli and tomato fruit. The knowledge gained from this research will provide the tools to develop postharvest conditioning protocols by informed selection of hormetic stresses or a combination of stresses to achieve enhanced production of desired secondary metabolites. Phytochemical-enriched fresh fruits and vegetables are considered as a new class of functional foods. Preservation of fresh crops with enhanced attributes of health benefits and disease resistance will not only help the fresh produce industry to reduce postharvest losses, but also help them to ensure a healthier population.