基于蛋白组学研究1-MCP对菜豆纤维化调控机理

Fresh common bean (Phaseolus vulgaris L.) are more appreciated by consumers due to its bright color, sensorial and nutritional characteristics. However, it is a problem that prone to dehydration, fibrosis and thinning during storage and transportation, which seriously affect its nutritional and commercial value. The pod cellulose content increased, cell wall thickening, leading to fibrosis, it has become important quality deterioration problems of fresh common bean during storage. Previous study found that 1-MCP coupled with modified atmosphere packaging stored at low-temperature can effectively control fresh bean postharvest fibrosis during low temperature, but there is no related report that the regulation mechanism of 1-MCP on postharvest fibrosis of fresh common bean, still need to further study. This project intends to start from the 1-MCP on physical and chemical basis of fresh bean postharvest fibrosis regulation, screened the key protein of fibrosis by isobaric tag for relative and absolute quantification (iTRAQ), then clear the main biological function, metabolic process and regulatory pathway of key fibrosis proteins by using Slim GO and KEGG bioinformatics means, to explore the regulation mechanism of 1-MCP treatment on postharvest fibrosis of fresh common bean, which will provide the theoretical foundation and practical significance for the 1-MCP treatment in the control of the preservative application technology of fresh beans vegetables in the postharvest circulation.

鲜食菜豆因其色泽嫩绿、营养丰富深受欢迎，但贮运过程中极易出现失水、纤维化、果肉变薄等劣变问题，严重影响其食用和商业价值。贮藏期间豆荚纤维素含量增加，细胞壁增厚，引起其纤维化，采后纤维化已成为贮藏期间鲜食菜豆品质劣变的重要问题。课题组前期研究发现1-MCP熏蒸结合自发气调包装低温贮藏能有效调控鲜食菜豆采后纤维化进程，但1-MCP对鲜食菜豆采后纤维化调控机理研究尚无报道，仍需进一步深入研究。本课题拟从1-MCP处理对鲜食菜豆采后纤维化调控的理化基础入手，利用相对和绝对定量同位素标记（iTRAQ）定量蛋白组学技术筛选出鲜食菜豆采后纤维化关键蛋白，通过GO Slim、KEGG等生物信息学分析手段明确纤维化关键蛋白的主要生物功能、代谢过程及其调控通路，探讨1-MCP处理对鲜食菜豆采后纤维化的调控机理，为1-MCP处理在鲜食豆类蔬菜采后流通环节中保鲜技术应用研究奠定理论基础和实际意义。

鲜食菜豆因其色、香、味及营养特性深受喜爱。然而采后失水、自身代谢消耗导致豆荚变薄，尤其是木质纤维化引起的豆筋增长、色泽消褪，严重影响其食用和商业价值。为此，本课题从生理效应、组织形态、理化指标、蛋白组学、基因表达等方面开展温度、运输条件、保鲜剂研究，深入开展1-MCP对鲜食菜豆采后木质纤维化调控机理。研究发现，9℃下贮藏能延缓其呼吸高峰的出现，减少失重，维持其食用品质；鲜食青棒豆适合于25℃下短时运输，长距离运输时应结合保鲜剂使用；高浓度二氧化氯缓释保鲜剂加快腐烂，涂膜处理和天然固体保鲜剂均能显著抑制贵阳青棒豆腐烂率的增加，三种保鲜剂处理显著抑制失重率和呼吸速率增加，抑制纤维素的增加，维持其品质；6-BA能有效延缓鲜食菜豆贮藏期间腐烂率、失重率和纤维素含量的增加，维持其硬度、色泽和蛋白质含量的相对稳定，从而维持鲜食菜豆的食用品质；采后0.5 μL L-1 1-MCP能有效抑制还原糖向纤维素的转化, 从而延缓其豆筋长度、相对电导率的增加，延缓豆荚相对厚度降低，从而延缓鲜食菜豆纤维化、维持食用品质；1-MCP通过调控乙烯和ABA合成及响应关键蛋白，下调氧化磷酸化、苯丙烷生物合成和内质网蛋白质加工途径关键蛋白质表达，上调半乳糖代谢、聚糖降解、糖酵解/糖异生等途径关键蛋白质表达；1-MCP显著抑制鲜食菜豆贮藏期间PvACO1基因、加强PvETR1和PvAOG1基因表达，抑制木质化细胞群增加、后壁组织增厚维管束增厚、木质化细胞生长，显著抑制鲜食菜豆的呼吸速率的增加、豆荚相对厚度下降，通过抑制蔗糖合成酶、蔗糖磷酸合成酶活性及基因表达，抑制还原糖向纤维素转化；通过延缓PAL、4CL、CAD和COMT等木质素合成途径关键酶活性及基因表达，抑制的活性降低木质素单体合成，抑制POD活性延缓超氧阴离子向过氧化氢的转化，从而抑制木质素单体的聚合，最终实现抑制鲜食菜豆木质纤维化，从而较好维持鲜食青棒豆的食用品质，乙烯则相反。为1-MCP在鲜食豆类蔬菜采后贮藏保鲜应用奠定理论基础和实际意义。