Plant Tissue Culture and Genetic Engineering Lab, National Agri-Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali 140306, Punjab, India; Department of Biotechnology, Panjab University, Chandigarh 160014, India.
Plant Tissue Culture and Genetic Engineering Lab, National Agri-Food Biotechnology Institute (NABI), Department of Biotechnology, Ministry of Science and Technology (Government of India), Sector-81, Knowledge City, S.A.S. Nagar, Mohali 140306, Punjab, India.
Int J Biol Macromol. 2023 May 15;237:124124. doi: 10.1016/j.ijbiomac.2023.124124. Epub 2023 Mar 24.
l-Ascorbic acid (AsA) is a potent antioxidant and essential micronutrient for the growth and development of plants and animals. AsA is predominantly synthesized by the Smirnoff-Wheeler (SW) pathway in plants where the GDP-L-galactose phosphorylase (GGP) gene encodes the rate-limiting step. In the present study, AsA was estimated in twelve banana cultivars, where Nendran carried the highest (17.2 mg/100 g) amount of AsA in ripe fruit pulp. Five GGP genes were identified from the banana genome database, and they were located at chromosome 6 (4 MaGGPs) and chromosome 10 (1 MaGGP). Based on in-silico analysis, three potential MaGGP genes were isolated from the cultivar Nendran and subsequently overexpressed in Arabidopsis thaliana. Significant enhancement in AsA (1.52 to 2.20 fold) level was noted in the leaves of all three MaGGPs overexpressing lines as compared to non-transformed control plants. Among all, MaGGP2 emerged as a potential candidate for AsA biofortification in plants. Further, the complementation assay of Arabidopsis thaliana vtc-5-1 and vtc-5-2 mutants with MaGGP genes overcome the AsA deficiency that showed improved plant growth as compared to non-transformed control plants. This study lends strong affirmation towards development of AsA biofortified plants, particularly the staples that sustain the personages in developing countries.
抗坏血酸（AsA）是一种有效的抗氧化剂，也是动植物生长发育所必需的微量营养物质。在植物中，AsA 主要通过 Smirnoff-Wheeler（SW）途径合成，其中 GDP-L-半乳糖磷酸化酶（GGP）基因编码限速步骤。在本研究中，在 12 个香蕉品种中估算了 AsA，其中奈德拉恩（Nendran）成熟果实果肉中的 AsA 含量最高（17.2mg/100g）。从香蕉基因组数据库中鉴定了 5 个 GGP 基因，它们位于 6 号染色体（4 个 MaGGPs）和 10 号染色体（1 个 MaGGP）上。基于计算机分析，从奈德拉恩（Nendran）品种中分离出 3 个潜在的 MaGGP 基因，并在拟南芥中进行过表达。与非转化对照植物相比，所有三个 MaGGPs 过表达系的叶片中 AsA（1.52 至 2.20 倍）水平显著提高。其中，MaGGP2 作为植物中 AsA 生物强化的潜在候选基因脱颖而出。此外，用 MaGGP 基因对拟南芥 vtc-5-1 和 vtc-5-2 突变体进行互补测定，克服了 AsA 缺乏症，与非转化对照植物相比，表现出改善的植物生长。这项研究有力地证实了开发 AsA 生物强化植物的可行性，特别是在发展中国家维持人口的主食方面。
