Mellidou Ifigeneia, Moschou Panagiotis N, Ioannidis Nikolaos E, Pankou Chryssa, Gėmes Katalin, Valassakis Chryssanthi, Andronis Efthimios A, Beris Despoina, Haralampidis Kosmas, Roussis Andreas, Karamanoli Aikaterini, Matsi Theodora, Kotzabasis Kiriakos, Constantinidou Helen-Isis, Roubelakis-Angelakis Kalliopi A
Department of Crop Production, School of Agriculture, Aristotle University of Thessaloniki Thessaloniki, Greece.
Department of Plant Biology and Linnean Center of Plant Sciences, Uppsala BioCentrum, Swedish University of Agricultural Sciences Uppsala, Sweden.
Front Plant Sci. 2016 Mar 31;7:379. doi: 10.3389/fpls.2016.00379. eCollection 2016.
Polyamines (PAs) are nitrogenous molecules that are indispensable for cell viability and with an agreed-on role in the modulation of stress responses. Tobacco plants with downregulated SAMDC (AS-SAMDC) exhibit reduced PAs synthesis but normal levels of PA catabolism. We used AS-SAMDC to increase our understanding on the role of PAs in stress responses. Surprisingly, at control conditions AS-SAMDC plants showed increased biomass and altered developmental characteristics, such as increased height and leaf number. On the contrary, during salt stress AS-SAMDC plants showed reduced vigor when compared to the WT. During salt stress, the AS-SAMDC plants although showing compensatory readjustments of the antioxidant machinery and of photosynthetic apparatus, they failed to sustain their vigor. AS-SAMDC sensitivity was accompanied by inability to effectively control H2O2 levels and concentrations of monovalent and divalent cations. In accordance with these findings, we suggest that PAs may regulate the trade-off between growth and tolerance responses.
多胺（PAs）是含氮分子，对细胞活力不可或缺，并且在调节应激反应中具有公认的作用。SAMDC基因下调的烟草植株（AS-SAMDC）表现出多胺合成减少，但多胺分解代谢水平正常。我们利用AS-SAMDC来增进对多胺在应激反应中作用的理解。令人惊讶的是，在对照条件下，AS-SAMDC植株表现出生物量增加以及发育特征改变，如株高增加和叶片数量增多。相反，在盐胁迫期间，与野生型相比，AS-SAMDC植株表现出活力下降。在盐胁迫期间，AS-SAMDC植株尽管显示出抗氧化机制和光合机构的代偿性重新调整，但它们未能维持其活力。AS-SAMDC的敏感性伴随着无法有效控制过氧化氢水平以及单价和二价阳离子浓度。根据这些发现，我们认为多胺可能调节生长和耐受反应之间的权衡。
