College of Agronomy, Qingdao Agricultural University, Qingdao, 266109, China.
Marine Agriculture Research Center, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
Plant Physiol Biochem. 2021 May;162:667-676. doi: 10.1016/j.plaphy.2021.03.034. Epub 2021 Mar 21.
Soil salinity is a major limiting factor for agricultural production, threatening food security worldwide. A thorough understanding of the mechanisms underlying plant responses is required to effectively counter its deleterious effects on crop productivity. Total flavonoid accumulation reportedly improves salinity tolerance in many crops. Therefore, we isolated the full-length cDNA of a flavonol synthetase (FLS) gene from Apocynum venetum (AvFLS). The gene contained a 1008-bp open reading frame encoding a protein composed of 335 amino acid residues. Multiple sequence alignment showed that the AvFLS protein was highly homologous to FLSs from other plants. AvFLS was expressed in leaves, stems, roots, flowers, and germinated seeds. Expression pattern analysis revealed that AvFLS was significantly induced by salinity stress. AvFLS overexpression in tobacco positively affected the development and growth of transgenic plants under salinity stress: root and seedling growth were inhibited to a lesser extent, while seed germination rate increased. Additionally, the overexpression of AvFLS under salinity stress resulted in an increase in total flavonoid content (1.63 mg g in wild-type samples and 4.63 mg g on average in transgenic samples), which accompanied the increase in the activity of antioxidant enzymes and inhibited the production of reactive oxygen species. Further, AvFLS-overexpressing transgenic tobacco plants absorbed more K than wild type plants, leading to an increased K/Na ratio, which in turn contributed to the maintenance of Na/K homeostasis. These findings suggest that an AvFLS-induced increase in total flavonoid content enhanced plant salinity tolerance, implying the importance of AvFLS gene responses to salinity stress.
土壤盐度是农业生产的主要限制因素，威胁着全球的粮食安全。为了有效应对其对作物生产力的有害影响，需要深入了解植物响应的机制。据报道，总类黄酮的积累可提高许多作物的耐盐性。因此，我们从罗布麻（Apocynum venetum）中分离出黄酮醇合成酶（FLS）基因的全长 cDNA（AvFLS）。该基因包含一个 1008bp 的开放阅读框，编码由 335 个氨基酸残基组成的蛋白质。多重序列比对表明，AvFLS 蛋白与其他植物的 FLS 高度同源。AvFLS 在叶片、茎、根、花和萌发的种子中表达。表达模式分析表明，AvFLS 受到盐胁迫的显著诱导。烟草中 AvFLS 的过表达在盐胁迫下对转基因植物的发育和生长产生了积极影响：根和幼苗的生长受到的抑制较小，而种子发芽率增加。此外，在盐胁迫下过表达 AvFLS 导致总类黄酮含量增加（野生型样品中为 1.63mg/g，平均在转基因样品中为 4.63mg/g），同时抗氧化酶的活性增加，抑制了活性氧的产生。此外，过表达 AvFLS 的转基因烟草植物比野生型植物吸收更多的 K，导致 K/Na 比值增加，从而有助于维持 Na/K 平衡。这些发现表明，AvFLS 诱导的总类黄酮含量增加增强了植物的耐盐性，表明 AvFLS 基因对盐胁迫的响应很重要。
