NO介导褪黑素调控采后荔枝果实抗冷性的机制研究

冷害是制约冷敏型果实低温贮运的主要因素。新型植物激素-褪黑素具有提高果实抗冷性的重要作用；胁迫环境或外源诱导物激发产生的NO是植物抗逆反应的原初信号分子之一。然而，人们目前对NO是否介导褪黑素调控果实抗冷性及其作用机制尚缺乏足够认识。本项目以荔枝果实为研究对象，通过褪黑素、褪黑素结合NO猝灭剂或合成抑制剂等处理方法，综合植物生理生化、细胞生物学和分子生物学等学科方法，利用激光共聚焦显微镜、透射电镜、基因克隆、qRT-PCR和修饰蛋白质组学等技术手段，研究冷藏过程中及冷藏后果实内源褪黑素与NO含量的动态变化、NO的生成途径，分析NO积累差异与抗冷相关生理代谢及冷适应相关转录因子基因表达的关系，鉴定与抗冷相关的S-亚硝基化蛋白并分析NO信号调控网络，明确NO在褪黑素诱导荔枝果实抗冷性中的作用及相关调控机制。研究结果可加深人们对果实冷害机制的认识，也为更有效地利用新型水果抗冷保鲜剂提供理论依据。

Chilling injury (CI) is a main factor restraining the low- temperature storage and transportation of cold-sensitive fruit. Melatonin, as a new plant hormone, has been shown to play an important role in enhancing cold tolerance of fruit. Nitric oxide (NO) generation stimulated by environmental factor or inducers has been considered as an original signal molecule to confer high protection against abiotic and biotic stress in plants. However, it is far from clear whether melatonin-regulated cold tolerance in fruit might depend on NO and its mechanism of action. By using harvested litchis as object in this proposed project, fruit will be treated with exogenous melatonin, NO scavenger /synthetic inhibitors and their combinations. What we propose in this project is to use multidisciplinary approaches including plant physio-chemistry, cell biology and molecular biology in the combination with multiple technologies involving in laser confocal scanning microscopy (LSCM), transmission electron microscope (TEM), gene clone, real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) and modified proteomics. Our proposed investigations cover the following three important aspect: namely, 1) the dynamic change of endogenous melatonin and NO as well as the synthetic pathway of NO, 2) the relationship among the differential accumulation of NO, cold tolerance-related physiological metabolism and transcription factor genes expression, 3) identification of S-nitrosylated proteins associated with chilling tolerance while analyzing the regulating networks of NO signaling in litchi fruit during cold storage and removal to ambient condition. It is believed that these planned investigations can eventually provide the highly desired results in finding the effects and regulated mechanism of NO related to melatonin-induced chilling tolerance. Furthermore, these results would greatly help to deepen the understanding of the CI mechanism in fruit and serve a theoretical evidence for application of novel preservative in postharvest production.