‘马家柚’果实发育期有机酸含量变化及柠檬酸代谢相关基因的表达分析  

Analysis of Organic Acid Content and Expression of Citric Acid Metabolism Related Genes During Fruit Development of ‘Majia’ Pomelo

作　　者：易明亮 张王妮 杨莉[1] 匡柳青 刘德春[1] 刘勇[1] 胡威 YI Mingliang;ZHANG Wangni;YANG Li;KUA(College of Agronomy,Jiangxi Agricultural University/Engineering Center of‘Jinggang’Honey Pomelo Breeding and Cultivation Technology of Jiangxi Province,Nanchang 330045,China;Shaanxi Fontaine Belle Biological Technology Co.Ltd,Baoji,Shaanxi 721199,China)

机构地区：[1]江西农业大学农学院/江西省井冈蜜柚繁育与栽培技术工程中心,江西南昌330045 [2]陕西枫丹百丽生物科技有限公司,陕西宝鸡721199

出　　处：《江西农业大学学报》2022年第4期841-851,共11页Acta Agriculturae Universitatis Jiangxiensis

基　　金：国家自然科学基金项目(31860539)。

摘　　要：【目的】明确江西省地方特色品种‘马家柚’果实发育期有机酸的变化规律及其与柠檬酸相关基因表达量的关系,揭示‘马家柚’果实品质形成的分子机制。【方法】研究以‘马家柚’发育期果实为材料,应用高效液相色谱技术(HPLC)测定花后60~210 d果实中有机酸组分及含量,以及通过荧光定量PCR分析柠檬酸合成、转运和降解相关基因表达量的变化,分析柠檬酸变化规律与相关基因表达量的联系。【结果】‘马家柚’果实发育期有机酸呈先上升后下降的趋势,柠檬酸含量占总有机酸的45.51%~81.47%,且其变化趋势与有机酸变化趋势一致。在整个果实发育期柠檬酸合成基因CmPEPC1、CmPEPC2、CmCS1和CmCS2相对表达量变化与柠檬酸含量变化趋势不同;柠檬酸运输相关基因CmCHX和CmVHP2表达量的变化与柠檬酸积累趋势也不一致,但CmDIC基因在果实发育前期的下调表达促进了柠檬酸的快速积累,同时CmVHA-c4的表达与柠檬酸积累密切相关;与降解相关的CmGS2和CmACLβ1基因均在柠檬酸快速增长期时开始下调表达,但在果实成熟期柠檬酸含量下降时表达量变化不大。同时CmAco3、CmGAD5和CmGABA-T均在花后210 d果实成熟期柠檬酸含量下降时表达量达到最高并且显著高于花后195 d。【结论】‘马家柚’果实有机酸在果实膨大期持续上升,而在成熟期后开始下降,并且有机酸的含量及变化趋势均由柠檬酸决定。柠檬酸的积累不受柠檬酸合成相关基因表达的直接影响,而是由柠檬酸转运载体基因以及降解基因的表达决定。在果实发育前中期,柠檬酸的积累主要受CmDIC、CmVHAc4、CmGS2以及CmACLβ1基因的调控,其降解主要通过谷氨酰胺和乙酰辅酶A途径进行,而在果实发育后期柠檬酸的积累在受CmVHA-c4基因调控的同时也受CmAco3、CmGAD5和CmGABA-T的调控,其降解主要通过GABA途径进行。[Objective]This study aims to determine the variation of organic acid content and its relationship with the expression of citric acid metabolism-related genes in ‘Majia’ pomelo during the fruit development and ripening,thus revealing the molecular mechanism of citrus fruit quality formation.[Method]The content of organic acid in the fruit at 60-210 days post-anthesis(DPA)of ‘Majia’ pomelo was detected with highperformance liquid chromatography(HPLC).The relative expression of genes involved in the citric acid synthesis,transport,and degradation were analyzed by real-time fluorescence quantitative PCR(qPCR).Finally,the correlation between the change of citric acid content and the expression level of metabolism-related genes was analyzed.[Result]The organic acids concentration of ‘Majia’ pomelo fruits increased first and then decreased during the development period.Citric acid content accounted for 45.51%-81.47% of the total organic acids,and its changing trend was consistent with that of organic acids.The change of relative expression of citrate synthesis genes CmPEPC1,CmPEPC2,CmCS1,and CmCS2.was inconsistent with the change trend of citric acid accumulation.The relative expression of citric acid transport-related genes CmCHX and CmVHP2 had no relationship with citric acid accumulation,but the down-regulated expression of the CmDIC gene promoted the rapid accumulation of citric acid in the early stage of fruit development,and the expression of the proton pump gene CmVHA-c4 was also closely related to citric acid accumulation.Citric acid degradation-related genes CmGS2and CmACLβ1 began to be down-regulated during the period of citric acid rapid accumulation,but their expression levels did not change significantly when the citric acid content decreased during the fruit ripening period.Simultaneously,the expression level of CmAco3,CmGAD5,and CmGABA-T genes all reached peak value when the citric acid content decreased on the 210 DPA which is fruit ripening period,were significantly higher than these genes

关 键 词：‘马家柚’ 果实发育 柠檬酸 基因表达 

分 类 号：S666.2[农业科学—果树学]