提高番茄品质的番茄去泛素化酶基因AMSH3

Tomato de-ubiquitination enzymes AMSH3 gene improving tomato quality

AMSH3酶是去泛素化酶中MPN(+)/JAMM蛋白酶家族的一员,能结合泛素化蛋白上的泛素分子。文章在番茄中发现了一去泛素化酶基因SlAMSH3,与拟南芥去泛素化酶基因AtAMSH3在核酸水平和蛋白水平分别有81%和71%的相似性。拟南芥中去泛素化酶AtAMSH3会影响植物液泡的形成和液泡蛋白的运输途径。文章构建了SlAMSH3果实特异表达的过表达载体,并通过根瘤农杆菌介导转化到野生型番茄中,通过筛选获得SlAMSH3在果实中高表达阳性株系,实时荧光定量聚合酶链式反应(polymerase chain reaction,PCR)分析显示,转基因番茄果实中SlAMSH3的表达量明显高于野生型果实(p<0.05)。文章测定了阳性番茄株系绿熟期果实叶绿素质量浓度及红熟期果实的单果质量、果实糖度、果实硬度、番茄红素质量浓度和β-胡萝卜素质量浓度。结果表明,转基因番茄果实的叶绿素总质量浓度、番茄红素和β-胡萝卜素比野生型分别提高178.61%、40.53%和74.86%,其他指标无显著差异。因此,SlAMSH3果实特异过表达的方法能够改良番茄果实品质,为基因工程方法改良番茄果实品质做出了新尝试。

AMSH3 enzyme is a member of de-ubiquitination enzymes in MPN（ ＋）/JAMM protease family, which can bind ubiquitinated protein ubiquitin molecule. The similarities of the de-ubiquitination enzyme gene SlAMSH3 in tomato were 81% and 71% in nucleic acid and protein levels in comparison with AtAMSH3 enzyme gene in Arabidopsis thaliana. In Arabidopsis, the formation of vacuole and the pathway to transport vacuole protein are affected by de-ubiquitination enzymes AMSH3. In this paper, the SlAMSH3 fruit-specific overexpression vector was constructed and transferred into tomato plants through a reproducible agrobacteriurn-mediated transformation. The transgenic plants expressing SlANISH3 highly in fruit were confirmed by screening. The analysis result of fluorescence quantitative reverse transcription polymerase chain reaction（RT- PCR） showed that the expression quantity of SlAMSH3 increased in the transgenic plants compared to that of wild type plants. The chlorophyll concentration of the positive tomato at green ripe stage and the single fruit weight, brix content, firmness, lycopene concentration and ~carotene concentration of the fruit at red ripe stage were determined. The chlorophyll concentration, lycopene, 13-carotene in the transgenic tomato fruit were improved 178. 61%, 40. 53% and 74. 86% respectively, while other indicators showed no significant differences. Therefore, fruit-specific overexpression of tomato SlAMSH3 is a useful genetic engineering approach to improve fruit quality.