Msr介导的NAC转录因子亚砜化调节参与调控香蕉果实采后衰老的机制研究

植物中转录因子的调控主要涉及磷酸化、泛素化、SUMO化、甲基化、乙酰化等，目前并无亚砜化[甲硫氨酸(Met)残基可逆性氧化]调控的报道。甲硫氨酸亚砜还原酶（Msr）能修复被氧化的蛋白质Met残基，在延缓生物体衰老和响应氧化胁迫中发挥重要作用。我们前期的研究发现，香蕉果实中与成熟衰老相关的转录因子MaNAC42可能为MaMsrB2的目标蛋白。本项目以香蕉果实为材料，拟从NAC转录因子亚砜化修饰对衰老相关基因表达调控的角度，研究果实采后成熟衰老的机理及调控机制。主要内容包括：分析香蕉果实采后衰老特性；解析香蕉MaMsrB2对MaNAC42的氧化还原调控机制；鉴别香蕉果实中MaNAC42的靶标基因；验证MaMsrB2介导的MaNAC42氧化还原调节参与调控香蕉采后衰老相关基因的转录。研究结果对于深入揭示采后水果衰老机理具有重要意义，将为研发保鲜技术以延长果实贮运期和降低采后损耗提供理论依据。

Study on the regulation of transcription factors in plants involves phosphorylation, ubiquitination, SUMO, methylation and acetylation. However, little information on regulation of transcription factor sulfoxidation (reversible oxidation of methionine residues) is available. Methionine sulfoxide reductase (Msr) plays an important role in delaying aging and resistance to oxidative stress by repairing the oxidized methionine resides in proteins. Our previous study showed that MaNAC42, a senescence-related transcription factor in banana fruit, possibly was the target of MaMsrB2. In this project, the mechanism of fruit ripening and senescence were studied from the perspective of the regulation of sulfoxidation of NAC transcription factor on the expression of senescence-related genes. The following issues will be studied: the senescence characteristics of postharvest banana fruit; the redox regulatory mechanism of MaNAC42 transcription factor by MaMsrB2; Identification of the target genes of MaNAC42; the involvement of MaMsrB2-mediated redox modification of MaNAC42 in regulating the expression of senescence-related genes. The results of the project have important significance for revealing the mechanism of postharvest fruit senescence and will provide a theoretical basis for prolonging fruit storage and transportation period and reducing postharvest losses, and thereby improving fruit industry economy benefit.