桃沙红果实α-甘露糖苷酶基因(α-man)克隆及其在软化过程中的表达分析  

Cloning and Expression Analysis of α-mannosidase Gene(α-man) During Fruit Softening of Peach cv. Shahong(Prunus persica)

作　　者：罗川[1] 曹丽军[1] 赵彩平[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》2013年第9期1060-1067,共8页Journal of Agricultural Biotechnology

基　　金：国家自然科学基金(No.31101514/C150102);国家高技术研究发展计划(863)项目(No.2011AA10020600-01)

摘　　要：α-甘露糖苷酶(α-man)是植物体内N聚糖加工的关键酶,在控制果实软化和延长货架期方面起重要作用。明确α-man在桃果实软化中的生理功能及其调控机制对进一步阐明桃果实的成熟软化机理具有重要意义。以商业成熟期桃(Prunus persica)沙红果实为材料,采用RT-PCR和RACE相结合的方法,克隆桃果实中α-man基因全长cDNA,并利用实时荧光PCR定量技术,检测了采后乙烯利和1-methylcyclopropene(1-MCP)处理沙红果实软化过程中α-man基因的表达差异。结果表明:桃果实α-man基因的cDNA全长长3 491 bp,包含一个3 075 bp完整的开放阅读框,编码1 024个氨基酸(Genbank登录号:JX310861),N端含有NXT/S的糖基化位点,属糖基水解酶38家族。实时荧光PCR定量技术检测发现对照果实在贮藏第2天出现α-man的表达高峰;外源乙烯处理α-man基因表达高峰提前1 d出现,且峰值显著高于对照果实;而1-MCP处理可使α-man基因的表达高峰延迟1 d,且后期α-man基因的表达受到极显著抑制。据此推断桃果实α-man基因可能受乙烯生成和乙烯信号转导途径的调控,参与桃果实的软化过程。α-mannosidase（a-man）, a key enzyme in the process of N-glycan, was reported to play an vital role in controlling fruit softening and extending shelf life. This is of important significance to make clear the physiological function and regulation mechanism of α-man during peach fruits softening for further clarifying the softening mechanism. A full length of a-man gene was cloned from mature peach （Prunus persica cv. Sha- hong） fruit by RT-PCR and RACE（rapid amplification of cDNA ends） methods, and its transcript levels under different treatments （ethrel and 1-methylcyclopropene（1-MCP） at room temperature） on peach fruit were fur- ther detected by Real-time quantitative PCR（qRT-PCR）. The results showed that the obtained t^-man gene, named Pp-a-man （GenBank accession No.JX310861）, was 3 491 bp in length, with a single 3 075 bp opening reading frame that predicted to encode 1 024 amino acids, which contained a NXT/S glycosylated site in the N-terminal region, and belonged to glycosyl hydrolase 3~ tamlly, qi, tl-v^t~ snowcu mat u,v ~Ar, l~ in control fruits increased to the first peak at 2 d after harvest. While in ethrel treatment, it reached to the maxi- mum at the first day, and the peak was significantly higher than that in the control. While in 1-MCP treatment, the peak time of a-man＇s expression was delayed 1 day and the a-man＇s expression was suppressed through the whole softening progress, especially at later stage. Therefore, the expression of a-man in peach fruits is concluded to be regulated by ethylene and ethylene signal transduction, and then participates in the softening process.

关 键 词：桃 果实 软化 α-甘露糖苷酶基因（α-man） 乙烯 

分 类 号：S856.9[农业科学—临床兽医学]