猕猴桃FAD基因家族鉴定及其在采后成熟过程中的表达分析  

Identification of the FAD gene family in kiwifruit and its expression anal-ysis during postharvest ripening

作　　者：杨彩宁 张雨培 杨聪聪 陈金印[1] 甘增宇 YANG Caining;ZHANG Yupei;YANG Congcong;CHEN Jinyin;GAN Zengyu(Jiangxi Provincial Key Laboratory for Postharvest Storage and Preservation of Fruits&Vegetables/Jiangxi Agricultural University,Nanchang 330045,Jiangxi,China)

机构地区：[1]果蔬贮藏与保鲜江西省重点实验室·江西农业大学,南昌330045

出　　处：《果树学报》2024年第11期2195-2213,共19页Journal of Fruit Science

基　　金：国家自然科学基金(32302627);江西省自然科学基金(20232BAB205040)。

摘　　要：[目的]分离并鉴定猕猴桃FAD基因家族成员,探究FAD基因在猕猴桃采后成熟过程中的表达模式及其与香气物质合成前体不饱和脂肪酸变化的关系。[方法]利用生物信息学方法鉴定并分析猕猴桃FAD基因家族成员,采用质构仪和气相色谱仪测定硬度和脂肪酸含量,借助实时荧光定量PCR验证FAD在采后成熟过程中的表达特性。[结果]在红阳猕猴桃基因组中共鉴定出了26个FAD基因,分为6个亚族;该家族大多为碱性蛋白,大部分定位于内质网中;这些成员不均匀地分布在19条染色体上,种内共有9对串联重复基因和22对片段重复基因;在其启动子区域上发现大量的光响应元件、植物激素响应元件、逆境胁迫响应元件和生长发育相关元件;表达模式分析和qPCR验证实验表明,AcFAD2.2表达量均随着成熟而不断显著上调;采后成熟过程中单不饱和脂肪酸(油酸)含量不断显著下降,双不饱和脂肪酸(亚油酸)含量则不断显著提高,多不饱和脂肪酸(亚麻酸)含量在成熟早期和中期无显著差别,而在后期显著降低;猕猴桃硬度采后出现快速下降,存在明显的后熟过程,此过程会形成特征香气酯类物质,而亚油酸又是酯类香气物质合成的主要前体物质。[结论]共鉴定了26个猕猴桃FAD基因成员,并筛选出了1个诱导猕猴桃采后成熟过程中亚油酸合成和积累的关键酶基因AcFAD2.2,亚油酸含量的增加伴随着猕猴桃后熟散发特征性香气,为进一步探究FAD基因参与猕猴桃采后成熟过程不饱和脂肪酸转化和香气合成的生物学功能提供了参考依据。【Objective】Unsaturated fatty acids play many physiological roles in plants,including the formation of triglycerides to provide energy for plant life activities;maintaining cell membrane homeo-stasis as a key component of cell membranes;participating in hormone regulation and signaling during biotic stress;playing an important role in responding to adversity such as low temperature and drought;and participating in synthesizing aroma substances as precursors during fruit ripening via the LOX path-way,α-oxidation pathway,orβ-oxidation pathway.During fruit ripening,the unsaturated fatty acids are used as precursors to synthesize aroma substances through the LOX pathway,α-oxidation pathway,orβ-oxidation pathway.At the same time,the unsaturated fatty acids also help the human body in numerous ways,including lowering lipids and blood pressure,enhancing fat metabolism,decreasing thrombosis,enhancing autoimmunity,and having anti-tumor properties.However,the human body is unable to syn-thesize unsaturated fatty acids,such as linoleic acid and linolenic acid,which can only be ingested from the diet.The animal body contains a high concentration of saturated fatty acids,whereas the plant body contains primarily unsaturated fatty acids.The fatty acid desaturases(FADs)are a group of enzymes that carry out the desaturation process,transforming saturated fatty acids into unsaturated fatty acids.To date,the FAD gene family has been identified in several species;however,it has not been reported in ki-wifruit.In addition,most of the current studies on FAD genes have focused on the antistress function of unsaturated fatty acids,with little focus on how these fatty acids affect aroma volatiles.Therefore,the aim of this study was to isolate and characterize the kiwifruit FAD gene family and to clarify its expres-sion pattern in kiwifruit during postharvest ripening and its relationship with the changes in unsaturated fatty acids,so as to lay a theoretical foundation for analyzing the formation of characteristic aroma in ki-wifr

关 键 词：猕猴桃 FAD基因家族 不饱和脂肪酸 香气合成 基因表达 

分 类 号：S663.4[农业科学—果树学]