Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
Applied Phycology and Biotechnology Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar, Gujarat, 364002, India.
Mol Biol Rep. 2022 May;49(5):3729-3743. doi: 10.1007/s11033-022-07213-7. Epub 2022 Feb 9.
Plant establishment, growth, development and productivity are adversely affected by abiotic stresses that are dominant characteristics of environmentally challenged/degraded habitats created in the Anthropocene. Crop breeding for climate resilience properties is need of the hour to sustain the crop productivity. We report on the characterization of Kappaphycus alvarezii (a red seaweed) Na/H antiporter gene (KaNa/H) for enhanced salt and osmotic stress tolerance.
The KaNa/H antiporter gene was cloned and over-expressed in tobacco under the control of CaMV35S promoter. Transgenic analysis was carried out to assess the stress tolerance ability of tobacco over-expressing KaNa/H antiporter gene.
Over-expression of KaNa/H gene improved the seed germination and seed vigor index under stress. Transgenic plants grew better and exhibited delayed leaf senescence. Improved K/Na, carotenoid/total chlorophyll and relative water content; lower accumulation of reactive oxygen species (ROS), MDA and Na; lower electrolyte leakage; better membrane stability index and accumulation of K, photosynthetic pigment, starch, sugar, free amino acid, proline and polyphenol contents indicated better physiological health of the transgenic tobacco under stress. Transgenic tobacco exhibited higher photosynthesis, photosystem II efficiency, electron transfer rate, photochemical quenching and activity of water splitting complex. Compared with control tobacco, transgenic tobacco exhibited higher expression of stress-defence genes under stress and better recovery after long-term osmotic stress.
Lower Na cytotoxicity, lower accumulation of ROS and maintenance of the membrane integrity helped transgenic tobacco to maintain the physiological functioning under stress. Present results established K. alvarezii as a potential gene resource and the KaNa/H antiporter gene as a potential candidate gene in molecular breeding of crops for development of the degraded land.
植物的建立、生长、发育和生产力都会受到非生物胁迫的不利影响，而这些胁迫是人类世所造成的具有挑战性/退化的环境的主要特征。为了提高作物对气候的适应能力，需要进行作物的耐气候育种，以维持作物的生产力。我们报告了卡拉胶海藻（一种红海藻）Na/H 反向转运蛋白基因（KaNa/H）的特性，该基因可增强盐和渗透胁迫耐受性。
克隆 KaNa/H 反向转运蛋白基因并在烟草中通过 CaMV35S 启动子进行过表达。通过转基因分析来评估过表达 KaNa/H 反向转运蛋白基因的烟草的胁迫耐受能力。
过表达 KaNa/H 基因可提高胁迫下的种子萌发和活力指数。转基因植株生长更好，叶片衰老延迟。提高了 K/Na、类胡萝卜素/总叶绿素和相对含水量；降低了活性氧（ROS）、MDA 和 Na 的积累；降低了电解质渗漏；更好的膜稳定性指数和 K、光合色素、淀粉、糖、游离氨基酸、脯氨酸和多酚含量表明，在胁迫下，转基因烟草具有更好的生理健康。与对照烟草相比，在胁迫下，转基因烟草的应激防御基因表达更高，在长期渗透胁迫后恢复更好。
较低的 Na 细胞毒性、ROS 积累减少和膜完整性的维持有助于转基因烟草在胁迫下维持生理功能。本研究结果确立了卡拉胶海藻作为一种潜在的基因资源，以及 KaNa/H 反向转运蛋白基因作为作物分子育种的一个潜在候选基因，用于退化土地的开发。
