ARC Centre of Excellence in Plant Energy Biology, Centre for Comparative Analysis of Biomolecular Networks, M316, The University of Western Australia, Crawley, WA, Australia.
Plant Signal Behav. 2011 Oct;6(10):1612-5. doi: 10.4161/psb.6.10.17107. Epub 2011 Oct 1.
Anoxia can occur in crop fields when flooding forms a physical barrier that reduces oxygen availability. Rice, but not wheat, can germinate and elongate its coleoptile under anoxia, providing an excellent model for understanding mechanisms of anoxia tolerance. We have shown differential molecular responses of rice and wheat coleoptiles to anoxia and discovered novel metabolic adaptations in amino acid metabolism for tissue tolerance. In this addendum, we elaborate on our discussion to speculate on the functions of differentially regulated proteins and their possible roles in selective transcription and translation, alternative elongation strategies and preparedness for exposure to air. In addition, it is thought that rapid growth is a stress avoidance strategy; if adequate coleoptile growth occurs then plants can outgrow floodwaters to resume or begin aerobic respiration. An innate response mechanism to the arrival of air, and the oxidative stress inherent to this, would therefore be necessary in survival beyond the alleviation of anoxia. Thus, we emphasize the importance of recognizing anoxia as a multi-stage stress where responses otherwise considered counter-intuitive may have evolved as preparative defenses for when exposure to air occurs.
当洪水形成物理屏障,减少氧气供应时,作物田可能会发生缺氧。在缺氧条件下,水稻而非小麦可以发芽并延长其胚芽鞘,为理解缺氧耐受机制提供了极好的模型。我们已经观察到水稻和小麦胚芽鞘对缺氧的分子反应存在差异,并发现了氨基酸代谢在组织耐受方面的新的代谢适应。在本附录中,我们详细讨论了差异调节蛋白的功能及其在选择性转录和翻译、替代伸长策略以及为暴露在空气中做好准备方面的可能作用。此外,人们认为快速生长是一种避免压力的策略;如果胚芽鞘生长充分,那么植物可以生长到洪水之上,恢复或开始有氧呼吸。因此,在缓解缺氧之后,需要一种对空气到来的先天反应机制,以及由此产生的氧化应激,这对于生存至关重要。因此,我们强调认识到缺氧是一种多阶段应激的重要性,否则,当暴露在空气中时,可能会进化出一些看似违反直觉的反应,作为预备性防御。