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在高等植物中醛糖酸内酯酶(Alase)催化L-半乳糖酸(L-Gal A)形成抗坏血酸(Ascorbic acid,As A)的前体物质L-半乳糖-1,4-内酯(L-Ga IL),是As A合成分支途径D-半乳糖醛酸途径中的关键步骤.基于最新的猕猴桃基因组数据库,分离并克隆到3个Alase家族基因,分别命名为Alase1、Alase2、Alase3,并从基因信息、蛋白质理化性质、二级结构及序列特征方面对其进行预测及分析.结果表明,Alase为亲水性蛋白,二级结构主要以α-螺旋和不规则卷曲为主,3个Alase基因具有高度的相似性.定量RT-PCR分析表明3个Alase家族基因在不同组织中均有表达,且在成熟的叶片中表达量最高.同时在猕猴桃果实发育及成熟过程中,Alase家族基因在幼果中的表达水平较低,而在果实发育后期及果实成熟过程中表达量不断升高.本研究可为Alase家族基因后续功能研究及猕猴桃中As A生物合成和积累分子机制解析奠定基础.
In higher plants, aldonic acid lactase (Alase) catalyzes the formation of L-galactosyl (L-Gal A) ascorbic acid (Ascorbic acid, L-Ga IL), which is a key step in the D-galacturonic acid pathway of As A synthesis pathway.According to the latest kiwifruit genome database, three Alase family genes were isolated and cloned into Alase1, Alase2, Alase3, The results showed that Alase was a hydrophilic protein, the secondary structure mainly consisted of α-helix and irregular curl, and three Alase family gene was expressed in different tissues and the highest expression level in mature leaves.At the same time in the development and maturation of Kiwifruit, the gene of Alase family The expression level of Alase family gene in later stage of fruit development and fruit ripening is higher than that in young fruit.It is very important to study the follow-up function of Alase family gene and the molecular mechanism of As A biosynthesis and accumulation in Actinidia chinensis .