Antoniou Chrystalla, Zarza Xavier, Gohari Gholamreza, Panahirad Sima, Filippou Panagiota, Tiburcio Antonio F, Fotopoulos Vasileios
Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology Limassol, Limassol 3036, Cyprus.
Polyamine's Laboratory, Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
Plants (Basel). 2021 Jan 30;10(2):269. doi: 10.3390/plants10020269.
Salinity constitutes one of the most important causes leading to severe reduction in plant yield. Several reports correlate the accumulation of polyamines in plants with tolerance to abiotic stress cues. The present study examined three genotypes with differing sensitivities to salinity (TN1.11, tolerant; Jemalong A17, moderately sensitive; TN6.18, sensitive), with the aim of examining the genotype-specific involvement of the polyamine metabolic pathway in plant response to salinity. The study was carried out with leaves harvested 48 h after watering plants with 200 mM NaCl. A comprehensive profile of free polyamines was determined using high performance liquid chromatography. All genotypes showed spermidine and spermine as the most abundant polyamines under control conditions. In salinity conditions, spermine levels increased at the expense of putrescine and spermidine, indicating a drift of polyamine metabolism towards the synthesis of increasing polycationic forms as a stress response. The increasing balance between high and low polycationic forms was clearly diminished in the salt-sensitive genotype TN6.18, showing a clear correlation with its sensitive phenotype. The polyamine metabolic profile was then supported by molecular evidence through the examination of polyamine metabolism transcript levels by RT-qPCR. General suppression of genes that are involved upstream in the PA biosynthetic pathway was determined. Contrarily, an induction in the expression of genes involved in the biosynthesis of spermine and spermidine was observed, in agreement with the metabolic analysis. A significant induction in diamino oxidase expression, involved in the catabolism of putrescine, was specifically found in the sensitive genotype ΤΝ6.18, indicating a distinct metabolic response to stress. Present findings highlight the involvement of polyamines in the defense response of genotypes showing sensitivity to salt stress.
盐度是导致植物产量严重下降的最重要原因之一。几份报告将植物中多胺的积累与对非生物胁迫信号的耐受性联系起来。本研究考察了三种对盐度敏感性不同的基因型（TN1.11，耐盐；Jemalong A17，中度敏感；TN6.18，敏感），旨在研究多胺代谢途径在植物对盐度响应中的基因型特异性参与情况。该研究在给植物浇灌200 mM NaCl 48小时后采集叶片进行。使用高效液相色谱法测定了游离多胺的全面概况。在对照条件下，所有基因型均显示亚精胺和精胺是最丰富的多胺。在盐度条件下，精胺水平升高，腐胺和亚精胺水平降低，这表明多胺代谢向合成更多聚阳离子形式漂移，作为一种应激反应。在盐敏感基因型TN6.18中，高聚阳离子形式和低聚阳离子形式之间增加的平衡明显减弱，这与其敏感表型明显相关。然后通过RT-qPCR检测多胺代谢转录水平，以分子证据支持多胺代谢概况。确定了参与多胺生物合成途径上游的基因普遍受到抑制。相反，与代谢分析一致，观察到参与亚精胺和精胺生物合成的基因表达上调。在敏感基因型ΤΝ6.18中特别发现参与腐胺分解代谢的二胺氧化酶表达显著上调，这表明对胁迫有明显的代谢反应。目前的研究结果突出了多胺在对盐胁迫敏感的基因型的防御反应中的作用。
