Institute of Olive Tree, Subtropical Plants and Viticulture, Laboratory of Vegetable Crops, Heraklion, Greece.
Agricultural University of Athens, Department of Crop Science, Laboratory of Pomology, Iera Odos 75, Athens 118 55, Greece.
Gene. 2020 Feb 15;727:144230. doi: 10.1016/j.gene.2019.144230. Epub 2019 Nov 16.
Adverse conditions and biotic strain can lead to significant losses and impose limitations on plant yield. Polyamines (PAs) serve as regulatory molecules for both abiotic/biotic stress responses and cell protection in unfavourable environments. In this work, the transcription pattern of 24 genes orchestrating PA metabolism was investigated in Cucumber Mosaic Virus or Potato Virus Y infected and cold stressed tomato plants. Expression analysis revealed a differential/pleiotropic pattern of gene regulation in PA homeostasis upon biotic, abiotic or combined stress stimuli, thus revealing a discrete response specific to diverse stimuli: (i) biotic stress-influenced genes, (ii) abiotic stress-influenced genes, and (iii) concurrent biotic/abiotic stress-regulated genes. The results support different roles for PAs against abiotic and biotic stress. The expression of several genes, significantly induced under cold stress conditions, is mitigated by a previous viral infection, indicating a possible priming-like mechanism in tomato plants pointing to crosstalk among stress signalling. Several genes and resulting enzymes of PA catabolism were stimulated upon viral infection. Hence, we suggest that PA catabolism resulting in elevated HO levels could mediate defence against viral infection. However, after chilling, the activities of enzymes implicated in PA catabolism remained relatively stable or slightly reduced. This correlates to an increase in free PA content, designating a per se protective role of these compounds against abiotic stress.
逆境和生物胁迫会导致重大损失，并对植物产量造成限制。多胺（PAs）作为调节分子，参与非生物/生物胁迫反应和逆境下的细胞保护。在这项工作中，研究了黄瓜花叶病毒或马铃薯 Y 病毒感染和冷胁迫的番茄植株中，24 个调节 PA 代谢的基因的转录模式。表达分析显示，在生物、非生物或复合胁迫刺激下，PA 动态平衡的基因调控呈现出差异/多效模式，从而揭示了针对不同刺激的离散反应：（i）生物胁迫影响的基因，（ii）非生物胁迫影响的基因，和（iii）同时受生物/非生物胁迫调控的基因。结果支持 PAs 对生物和非生物胁迫的不同作用。在冷胁迫条件下显著诱导表达的几个基因，由于先前的病毒感染而受到缓解，这表明番茄植株中存在可能的类似引发的机制，表明胁迫信号之间存在串扰。一些基因和由此产生的 PA 分解代谢酶在病毒感染后被诱导。因此，我们认为 PA 分解代谢导致 HO 水平升高可能介导对病毒感染的防御。然而，在冷却后，参与 PA 分解代谢的酶的活性仍然相对稳定或略有降低。这与游离 PA 含量的增加相关，表明这些化合物本身对非生物胁迫具有保护作用。
