Short Eleri F, North Kathryn A, Roberts Michael R, Hetherington Alistair M, Shirras Alan D, McAinsh Martin R
Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
Plant J. 2012 Sep;71(6):948-61. doi: 10.1111/j.1365-313X.2012.05043.x. Epub 2012 Jul 9.
Changes in gene expression form a key component of the molecular mechanisms by which plants adapt and respond to environmental stresses. There is compelling evidence for the role of stimulus-specific Ca(2+) signatures in plant stress responses. However, our understanding of how they orchestrate the differential expression of stress-induced genes remains fragmentary. We have undertaken a global study of changes in the Arabidopsis transcriptome induced by the pollutant ozone in order to establish a robust transcriptional response against which to test the ability of Ca(2+) signatures to encode stimulus-specific transcriptional information. We show that the expression of a set of co-regulated ozone-induced genes is Ca(2+)-dependent and that abolition of the ozone-induced Ca(2+) signature inhibits the induction of these genes by ozone. No induction of this set of ozone-regulated genes was observed in response to H(2)O(2), one of the reactive oxygen species (ROS) generated by ozone, or cold stress, which also generates ROS, both of which stimulate changes in Ca(2+). These data establish unequivocally that the Ca(2+)-dependent changes in gene expression observed in response to ozone are not simply a consequence of an ROS-induced increase in Ca(2+) per se. The magnitude and temporal dynamics of the ozone, H(2)O(2) , and cold Ca(2+) signatures all differ markedly. This finding is consistent with the hypothesis that stimulus-specific transcriptional information can be encoded in the spatiotemporal dynamics of complex Ca(2+) signals in plants.
基因表达的变化构成了植物适应和应对环境胁迫的分子机制的关键组成部分。有确凿证据表明刺激特异性Ca(2+)信号在植物应激反应中发挥作用。然而，我们对它们如何协调应激诱导基因的差异表达的理解仍然支离破碎。我们对污染物臭氧诱导的拟南芥转录组变化进行了全面研究，以建立一个强大的转录反应，据此测试Ca(2+)信号编码刺激特异性转录信息的能力。我们发现一组共同调控的臭氧诱导基因的表达依赖于Ca(2+)，并且臭氧诱导的Ca(2+)信号的消除会抑制臭氧对这些基因的诱导。对于臭氧产生的活性氧（ROS）之一H(2)O(2)或同样产生ROS的冷胁迫（二者均刺激细胞质中[Ca(2+)]的变化），未观察到这组臭氧调控基因的诱导。这些数据明确表明，响应臭氧观察到的基因表达中Ca(2+)依赖性变化并非仅仅是ROS诱导的细胞质中[Ca(2+)]增加本身的结果。臭氧、H(2)O(2)和冷胁迫的Ca(2+)信号的强度和时间动态都明显不同。这一发现与以下假设一致：刺激特异性转录信息可以编码在植物中复杂Ca(2+)信号的时空动态中。
