两种不同耐贮性桃果实采后乙烯合成和果实软化相关基因表达的差异  

The Difference of Ethylene Biosynthesis and Expression of Softeningrelated Genes Between Two Peach(Prunus persica) Cultivars with Different Storage Property After Harvest

作　　者：苏素香 赵彩平[1] 曹丽军[1] 李金金[1] 李芳[1] 韩明玉[1] 

机构地区：[1]西北农林科技大学园艺学院,杨凌712100

出　　处：《农业生物技术学报》2015年第4期450-458,共9页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金(No.31101514/C150102);西北农林科技大学基本科研业务费专项资金(No.QN2011091)

摘　　要：以商业成熟期的桃(Prunus persica)栽培品种秦王(极耐贮)和沙红(不耐贮)为试材,采用气相色谱测定乙烯释放量;利用实时荧光定量PCR(quantitative Real-time PCR,q RT-PCR)技术分析乙烯合成关键酶和果实软化相关基因在两个品种中的表达差异。研究结果表明,秦王果实在贮藏期间ACC合成酶基因(1-aminocyclopropane-1-carboxylic acid synthase gene,Pp ACS1)相对表达量极低,乙烯释放速率也极低,一直保持较高的硬度;而沙红果实在贮藏过程中Pp ACS1的相对表达量随软化进程迅速增加,释放大量乙烯,果实硬度下降快。秦王果实中ACC氧化酶基因(1-aminocyclopropane-1-carboxylic acid oxidase gene,Pp ACO1)虽有一定的表达量,但没有随贮藏时间而增加;而Pp ACO1在沙红桃中随果实的软化表达量呈显著上升的趋势。秦王果实中细胞壁降解酶果胶甲酯酶基因(pectin methylesterase gene,Pp PME)和多聚半乳糖醛酸酶基因(polygalacturonase gene,Pp PG)的表达量都极低;而在沙红果实中其表达量均呈持续增加趋势。此外,秦王果实中扩张蛋白基因(expansin gene,Pp EXP)的表达量也较低;而在沙红中表达量较高。N-聚糖加工酶α-甘露糖苷酶基因(α-mannosidase gene,Ppα-Man)和β-氨基己糖苷酶基因(β-hexosaminidase gene,Pp Hex1,Pp Hex2)在沙红和秦王贮藏期间均有较高表达量,且秦王中的表达量显著高于沙红(P<0.05)。这表明秦王果实采后不软化是由于Pp ACS1的转录受阻,不能产生乙烯,从而致使细胞壁水解酶Pp PME和Pp PG几乎不表达,果胶代谢受阻,因而果实一直保持较高硬度;而沙红果实在采后贮藏中释放大量乙烯,促进了Pp EXP、Pp PME和Pp PG的表达,引起细胞壁果胶的大量降解,导致果实迅速软化。而Ppα-Man、Pp Hex1和Pp Hex2可能不是秦王软化过程的关键基因。本研究为阐明桃果实成熟软化机理及其高效培育耐贮品种提供基础资料。Two peach （Prunus persica） cultivars Qinwang （with good storage property） and Shahong （with poor storage property） fruits harvested at commercial maturity were investigated. We analysed the difference of ethylene production through gas chromatography approach, and the genes expressions involed in ethylene biosynthesis and fruit softening between the two peach cultivars by quantitative Real-time PCR PCR （qRT-PCR）. The results showed that Qinwang peach remained high firmness during storage accompanied by a quite low expression level ofACC synthase gene （1-aminocyclopropane-1-carboxylic acid synthase gene, PpACS1） and ethylene production rate. However, Shahong softened quikly, and the relative expression of PpACS1 was increased significantly, along with lot of ethylene produced. ACC oxidase gene （1-aminocyclopropane-1- carboxylic acid oxidase gene, PpACO1） expression did not increased in Qinwang while presented rising trend during Shahong softening. In Qinwnag, the expression of pectin methylesterase gene （PpPME） and polygalacturonase gene （PpPG） were extremely low, however, it increased continuously during Shahong softening. In addition, the expression level of expansin gene （PpEXP） was very low in Qinwang compared with Shahong. The gene expression of N-glycan processing enzymesα-mannosidase gene （Ppa-Man） and β- hexosaminidase gene （PpHexl and PpHex2） expression level were increased in both of Shahong and Qinwang, but the expression in Shahong were significantly higher than that in Qinwang （P〈0.05）. These results indicated that the delay of Qinwang fruit softening was due to lack of enough ethylene production by limited expression of PpACS1, which caused PpPME and PpPG expression and enzyme at lower level, unable to take the role in pectins degradation. However, Shahong softened rapidly as a result of production of ethylene, thus, PpEXP, PpPME and PpPG were induced and pectins degradated. Ppa-Man, PpHexl and PpHex2 maybe not key factors acting on Qinwang softenin

关 键 词：桃果实 软化 乙烯 果胶甲酯酶 多聚半乳糖醛酸酶 

分 类 号：S665.2[农业科学—果树学]