Asparagine synthetase (ASN) and glutamine synthetase (GS) play important roles in nitrogen metabolism and recycling in plants. In this study, we performed the characterization and expression analysis of the ASN and GS gene families in grape. It contains two ASN genes, VviASN1 and VviASN2, and five GS genes, VviGS1.1, VviGS1.2, VviGS1.3, VviGS2a and VviGS2b. For each gene, full-length complementary DNAs were cloned and the properties of encoded protein were predicted using bioinformatics approaches. Real-time PCR analysis showed that the transcript levels of VviASN1, VviASN2, VviGS1.1, VviGS1.2 and VviGS2b during ovule (seed) development were higher in seedless cultivars than in seeded. It was showed that asparagine (Asn) content in the seeds of seedless grapes was higher than in seeded, while glutamine (Gln) content was higher in seeded. Levels of both amino acids increased during early seed development, then decreased as development progressed. Based on correlation between amino acid content and gene expression, VviASN1 may play a major role in the synthesis of Asn in grape seeds. VviASN1 and VviASN2 were highly expressed in flower and leaf, respectively. VviGS1.1, VviGS2a and VviGS2b were highly expressed in leaf, while VviGS1.2 was highly expressed in root. In summary, our findings suggest novel roles for the VviASN and VviGS genes families during seed development/abortion in grapevine.

天冬酰胺合成酶 (ASN) 和谷氨酰胺合成酶 (GS) 在植物氮代谢和循环中发挥重要作用。在这项研究中，我们对葡萄中的ASN和GS基因家族进行了表征和表达分析。它包含两个ASN基因，VviASN1和VviASN2，以及五个GS基因，VviGS1.1、VviGS1.2、VviGS1.3、VviGS2a和VviGS2b。对于每个基因，克隆全长互补 DNA，并使用生物信息学方法预测编码蛋白质的特性。实时 PCR 分析表明VviASN1、VviASN2、VviGS1.1、VviGS1.2和胚珠（种子）发育过程中的VviGS2b在无籽品种中高于有籽品种。结果表明，无籽葡萄种子中天冬酰胺（Asn）含量高于有籽葡萄，而有籽葡萄籽中谷氨酰胺（Gln）含量较高。两种氨基酸的水平在早期种子发育期间增加，然后随着发育的进行而降低。根据氨基酸含量与基因表达的相关性，VviASN1可能在葡萄籽中 Asn 的合成中起主要作用。VviASN1和VviASN2分别在花和叶中高表达。VviGS1.1、VviGS2a和VviGS2b在叶片中高表达，而VviGS1.2在根中高度表达。总之，我们的研究结果表明VviASN和VviGS基因家族在葡萄藤种子发育/流产过程中的新作用。