The majority of stress-sensitive genes responds to cold and high light in the same direction, if plants face the stresses for the first time. As shown recently for a small selection of genes of the core environmental stress response cluster, pre-treatment of Arabidopsis thaliana with a 24 h long 4 °C cold stimulus modifies cold regulation of gene expression for up to a week at 20 °C, although the primary cold effects are reverted within the first 24 h. Such memory-based regulation is called priming. Here, we analyse the effect of 24 h cold priming on cold regulation of gene expression on a transcriptome-wide scale and investigate if and how cold priming affects light regulation of gene expression. Cold-priming affected cold and excess light regulation of a small subset of genes. In contrast to the strong gene co-regulation observed upon cold and light stress in non-primed plants, most priming-sensitive genes were regulated in a stressor-specific manner in cold-primed plant. Furthermore, almost as much genes were inversely regulated as co-regulated by a 24 h long 4 °C cold treatment and exposure to heat-filtered high light (800 μmol quanta m− 2 s− 1). Gene ontology enrichment analysis revealed that cold priming preferentially supports expression of genes involved in the defence against plant pathogens upon cold triggering. The regulation took place on the cost of the expression of genes involved in growth regulation and transport. On the contrary, cold priming resulted in stronger expression of genes regulating metabolism and development and weaker expression of defence genes in response to high light triggering. qPCR with independently cultivated and treated replicates confirmed the trends observed in the RNASeq guide experiment. A 24 h long priming cold stimulus activates a several days lasting stress memory that controls cold and light regulation of gene expression and adjusts growth and defence regulation in a stressor-specific manner.

中文翻译：

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冷启动使拟南芥中基因表达的光和冷调节解耦。

如果植物是第一次面对胁迫，大多数胁迫敏感基因会在同一方向上响应冷光和强光。如最近针对核心环境胁迫响应簇的一小部分基因显示的那样，用24小时长的4°C冷刺激对拟南芥进行预处理，可在20°C的情况下对基因表达进行冷调节长达一周。在最初的24小时内，主要的寒冷效应得以恢复。这种基于内存的调节称为启动。在这里，我们分析了24小时冷启动对转录组范围内基因表达的冷调节的影响，并研究了冷启动是否以及如何影响基因表达的光调节。冷启动会影响一小部分基因的冷光调节和过量光调节。与在未启动的植物中在冷和轻胁迫下观察到的强基因共同调控相反，在低温启动的植物中，大多数启动敏感基因以胁迫特异性的方式被调控。此外，几乎一样多的基因被24小时长的4°C低温处理和暴露于热滤过的高光（800μmol量子m-2 s-1）共同调控。基因本体论富集分析表明，冷启动优先支持冷触发时参与防御植物病原体防御的基因的表达。调节发生在涉及生长调节和运输的基因表达的成本上。相反，冷启动导致调节新陈代谢和发育的基因表达增强，而防御基因响应强光触发而表达较弱。具有独立培养和处理的重复序列的qPCR证实了在RNASeq指导实验中观察到的趋势。24小时长的启动冷刺激会激活持续数天的压力记忆，从而控制基因表达的冷光调节，并以应激源特异性方式调节生长和防御调节。