龙眼果实采后衰老过程中的能量转运与调控机制

Longan (Dimocarpus longan Lour.) is a main subtropical fruit in southern China. However, longan fruit deteriorate rapidly after harvest, which is the key limination factor of storage and fresh-keeping of postharvest longan fruit. Adenine nucleotide translocator (ANT) plays key roles in energy synthesis and energy supply in cells. Our previous studies suggest that postharvest senescence of longan fruit is associated with energy deficit. However, the occurrence mechanism of energy deficiency is still unclear. Moreover, the role of ANT on energy deficiency of postharvest longan fruit has not been reported. . In this project, energy status in longan fruit, the characteristics of transcriptional expression of ANT gene, mechanisms of ANT transcriptional regulation and the expression characteristics of of ANT protein will be studied to explore the characteristics and mechanisms of the expression of ANT gene during postharvest senescence process of longan fruit. In addition, bongkrekic acid (BKA), the ANT inhibitor, will be applied to identify the effects of inhibition of ANT on energy status and storage quality in longan fruit, and further verified the effect of the inhibition of ANT on energy deficiency . . The results of this project are expected to obtain a new theoretical basis for the energy deficit mechanisms in the process of postharvest senescence of longan fruit.

龙眼是中国南方主要的亚热带水果之一，但果实采后极易衰老变质，是限制采后龙眼果实贮藏保鲜的关键因素。腺苷酸转运蛋白（ANT）在细胞内能量合成和供给中起关键作用。我们前期的研究认为，采后龙眼果实衰老与能量亏缺密切相关，但采后龙眼果实能量亏缺发生的机理尚不清楚，有关ANT在龙眼果实采后能量亏缺发生中的作用机制未见报道。本项目拟从龙眼果实采后衰老过程中的能量特性、ANT基因的转录表达特性、ANT基因的转录调控、ANT蛋白的表达特性等方面，研究龙眼果实采后衰老过程中ANT的表达与调控机制；同时研究外源ANT抑制剂（米酵菌酸）对采后龙眼果实组织能量水平和贮藏品质的影响，来进一步证实ANT功能抑制在采后龙眼果实能量亏缺发生中的作用。研究成果可望在阐明龙眼果实采后衰老过程中能量亏缺发生的可能机制方面获得新的理论依据。

龙眼（Dimocarpus longan Lour.）是名优热带亚热带水果之一，但采后极易衰老劣变，极大地限制了其远距离运输和长期贮藏保鲜。近年研究表明，能量亏缺是导致采后果实衰老发生的重要因素。线粒体内膜上腺苷酸转运蛋白（adenine nucleotide translocator，ANT）所介导的能量物质转运在细胞能量合成和供给过程中起关键作用。ANT蛋白家族包括ATP/ADP转运蛋白(ATP/ADP carrier, AAC)、ATP/AMP转运蛋白（ATP/AMP transporter, ADNT）。有关能量转运在龙眼果实采后能量亏缺发生中的作用机制未见报道。.本项目以ANT为研究对象，从龙眼果实采后衰老过程中ANT基因的转录表达特性、ANT基因的转录调控因子的筛选、鉴定及其作用机制、ANT在蛋白水平的表达特性等多层次，深入研究龙眼采后衰老过程中的能量转运与调控机制；同时采用外源施加ANT作用抑制剂米酵菌酸（bongkrekic acid，BKA）研究ANT功能受抑制对于龙眼果实能量水平及果实品质的影响。.本项目研究结果表明，能量转运作用受抑制（BKA处理）可降低龙眼果皮能量水平，增加龙眼果皮细胞膜透性和果皮褐变指数，降低龙眼果实商品率，说明能量转运对维持采后龙眼细胞能量水平起重要作用。此外，DlAAC1、DlAAC4、DlAAC5、DlAAC7、DlADNT1和DlADNT2基因可能在龙眼果实采后衰老过程中对能量转运起主要作用。转录因子DlILR3、DlNAC和DlMYB可能参与调控DlADNT1基因的转录表达。有关DLANTs基因从转录水平到蛋白水平的表达调控及修饰需要进一步深入研究。本项目从能量转运的角度探究在龙眼果实采后衰老过程中的能量亏缺及其调控机制，为进一步调控龙眼果实采后衰老提供科学依据和理论指导。