植物会因为四季或昼夜的温度变化而调整生长状态,那么它们靠什么来感知外界温度变化呢?英国研究人员说,植物在基因层面有一个特殊的“温度计”。这一发现将有助于研究人员培育出更能适应当前气候变化的植物新品种。
英国约翰·英尼斯中心的研究人员在最新一期《细胞》杂志上报告说,他们利用拟南芥这种植物进行了实验。研究人员使用可以导致这种植物发光的基因手段,使其在温度越高的环境下能发出越多的光。
研究人员发现,一种名为H2A.Z的组蛋白是植物的“温度计”。当植物生长的环境温度较低时,这种组蛋白会绑在DNA(脱氧核糖核酸)上,使得一些基因无法发挥作用,从而抑制植物生长;而当温度升高时,它就会松开DNA,相关基因就可以发挥作用,指导植物生长。研究人员认为,一些植物随着天气冷暖而延后或提前开花,都是受这套系统控制。
但如果这种组蛋白因变异而出现问题时,植物就可能无法感知到外界温度变化。研究人员说,因为植物无法移动,如果它不能迅速适应某个地方的气温变化,就有在当地灭绝的危险。研究人员希望在了解植物温控系统的特点后,能培育出更能适应气候变化的植物新品种。(生物谷Bioon.com)
生物谷推荐原始出处:
Cell, Volume 140, Issue 1, 136-147, 8 January 2010 DOI:10.1016/j.cell.2009.11.006
H2A.Z-Containing Nucleosomes Mediate the Thermosensory Response in Arabidopsis
S. Vinod Kumar, Philip A. Wigge
Plants are highly sensitive to temperature and can perceive a difference of as little as 1°C. How temperature is sensed and integrated in development is unknown. In a forward genetic screen in Arabidopsis, we have found that nucleosomes containing the alternative histone H2A.Z are essential to perceiving ambient temperature correctly. Genotypes deficient in incorporating H2A.Z into nucleosomes phenocopy warm grown plants, and show a striking constitutive warm temperature transcriptome. We show that nucleosomes containing H2A.Z display distinct responses to temperature in vivo, independently of transcription. Using purified nucleosomes, we are able to show that H2A.Z confers distinct DNA-unwrapping properties on nucleosomes, indicating a direct mechanism for the perception of temperature through DNA-nucleosome fluctuations. Our results show that H2A.Z-containing nucleosomes provide thermosensory information that is used to coordinate the ambient temperature transcriptome. We observe the same effect in budding yeast, indicating that this is an evolutionarily conserved mechanism.