Luna Celina M, Pastori Gabriela M, Driscoll Simon, Groten Karin, Bernard Stephanie, Foyer Christine H
Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
J Exp Bot. 2005 Jan;56(411):417-23. doi: 10.1093/jxb/eri039. Epub 2004 Nov 29.
Plants co-ordinate information derived from many diverse external and internal signals to ensure appropriate control of gene expression under optimal and stress conditions. In this work, the relationships between catalase (CAT) and H2O2 during drought in wheat (Triticum aestivum L.) are studied. Drought-induced H2O2 accumulation correlated with decreases in soil water content and CO2 assimilation. Leaf H2O2 content increased even though total CAT activity doubled under severe drought conditions. Diurnal regulation of CAT1 and CAT2 mRNA abundance was apparent in all conditions and day/night CAT1 and CAT2 expression patterns were modified by mild and severe drought. The abundance of CAT1 transcripts was regulated by circadian controls that persisted in continuous darkness, while CAT2 was modulated by light. Drought decreased abundance, and modified the pattern, of CAT1 and CAT2 mRNAs. It was concluded that the complex regulation of CAT mRNA, particularly at the level of translation, allows precise control of leaf H2O2 accumulation.
植物整合来自多种不同外部和内部信号的信息，以确保在最佳和胁迫条件下对基因表达进行适当控制。在这项工作中，研究了小麦（Triticum aestivum L.）干旱期间过氧化氢酶（CAT）与H2O2之间的关系。干旱诱导的H2O2积累与土壤含水量和CO2同化作用的降低相关。即使在严重干旱条件下总CAT活性增加一倍，叶片H2O2含量仍会增加。在所有条件下，CAT1和CAT2 mRNA丰度的昼夜调节都很明显，轻度和重度干旱会改变CAT1和CAT2的昼夜表达模式。CAT1转录本的丰度受昼夜节律控制，在持续黑暗中依然存在，而CAT2则受光调节。干旱降低了CAT1和CAT2 mRNA的丰度，并改变了其模式。得出的结论是，CAT mRNA的复杂调节，特别是在翻译水平上，允许对叶片H2O2积累进行精确控制。
