NAC转录因子调控救心菜采后叶绿素降解的机制研究

Sedum aizoon L. is a new popular special vegetable with high nutritional value and health benefits. However, harvested Sedum aizoon L. is highly vulnerable to chlorisis during storage at room temperature, leading to serious quality and economic losses. In model plants, it was reported that NAC transcription factors play important roles in chlorophyll degradation. The regulation mechanism of chlorophyll degradation may be different from model plants, for the reason that harvested Sedum aizoon L. cannot absorb nutrition from environments. Nowadays, the mechanism of NAC transcription factors regulating chlorophyll degradation of harvested Sedum aizoon L is still largely unknown. In the present study, RNA-Seq was applied to screen related key enzyme genes and NAC transcription factors involved in chlorophyll degradation in Sedum aizoon L. The functional mode of NAC transcription factors regulating chlorophyll degradation key enzyme genes will be confirmed through DNA-protein, protein-protein interaction techniques, and tobacco transient expression system, to elucidate the mechanism of chlorophyll degradation at molecular level. These results will provide a theoretical basis for chlorophyll degradation regulation of harvested Sedum aizoon L. Moreover, the chlorophyll degradation mechanism will facilitate better understanding for postharvest preservation technology of other green vegetables.

救心菜（Sedum aizoon L.）是一种近年兴起的特色蔬菜，具有丰富营养和保健功效，深受人们青睐。但采后救心菜在常温条件下，易衰老褪绿导致品质下降，严重影响其商品价值。已有研究表明，NAC转录因子在模式植物叶片叶绿素降解中发挥重要作用。采后救心菜无外源营养物质供应，叶绿素降解调控机制可能与模式植物不同，目前NAC转录因子在采后救心菜叶绿素降解过程中的调控机制仍不明确。本项目拟以救心菜为试材，基于RNA-Seq转录组测序，筛选并鉴定采后救心菜叶绿素降解关键酶基因和NAC转录因子，通过DNA-蛋白质互作和蛋白质-蛋白质互作技术，以及烟草瞬时表达体系等手段，明确NAC转录因子对叶绿素降解关键酶基因的作用模式，从分子生物学角度阐明救心菜采后叶绿素降解的转录调控机制。研究结果将为调控救心菜采后叶绿素降解，延长贮藏保鲜期提供理论基础，也可为其他绿色蔬菜的叶绿素降解机理及采后调控技术提供借鉴。

救心菜是一种近年兴起的特色蔬菜，具有丰富营养和保健功效，深受人们青睐。但采后救心菜在常温条件下，易衰老褪绿导致品质下降，严重影响其商品价值。已有研究表明，NAC转录因子在模式植物叶片叶绿素降解中发挥重要作用。采后救心菜无外源营养物质供应，叶绿素降解调控机制可能与模式植物不同，目前NAC转录因子在采后救心菜叶绿素降解过程中的调控机制仍不明确。项目以救心菜为试材，研究了肉桂精油和褪黑素在处理在救心菜保鲜护绿上的作用。基于RNA-Seq转录组测序，筛选了采后救心菜差异表达的23个叶绿素降解关键酶基因和9个NAC转录因子。通过DNA-蛋白质互作和蛋白质-蛋白质互作技术，明确了CdNAC3和CdMIKC对叶绿素降解关键酶基因CdNYC和CdPAO的调控作用，从分子生物学角度阐明救心菜采后叶绿素降解的转录调控机制。研究结果为调控救心菜采后叶绿素降解，延长贮藏保鲜期提供理论基础。