Gawroński Piotr, Ariyadasa Ruvini, Himmelbach Axel, Poursarebani Naser, Kilian Benjamin, Stein Nils, Steuernagel Burkhard, Hensel Goetz, Kumlehn Jochen, Sehgal Sunish Kumar, Gill Bikram S, Gould Peter, Hall Anthony, Schnurbusch Thorsten
Leibniz Institute of Plant Genetics and Crop Plant Research, OT Gatersleben, D-06466 Stadt Seeland, Germany.
Genetics. 2014 Apr;196(4):1253-61. doi: 10.1534/genetics.113.158444. Epub 2014 Jan 17.
Viable circadian clocks help organisms to synchronize their development with daily and seasonal changes, thereby providing both evolutionary fitness and advantage from an agricultural perspective. A high-resolution mapping approach combined with mutant analysis revealed a cereal ortholog of Arabidopsis thaliana LUX ARRHYTHMO/PHYTOCLOCK 1 (LUX/PCL1) as a promising candidate for the earliness per se 3 (Eps-3A(m)) locus in einkorn wheat (Triticum monococcum L.). Using delayed fluorescence measurements it was shown that Eps-3A(m) containing einkorn wheat accession KT3-5 had a distorted circadian clock. The hypothesis was subsequently confirmed by performing a time course study on central and output circadian clock genes, which showed arrhythmic transcript patterns in KT3-5 under constant ambient conditions, i.e., constant light and temperature. It was also demonstrated that variation in spikelet number between wild-type and mutants is sensitive to temperature, becoming negligible at 25°. These observations lead us to propose that the distorted clock is causative for both early flowering and variation in spike size and spikelet number, and that having a dysfunctional LUX could have neutral, or even positive, effects in warmer climates. To test the latter hypothesis we ascertained sequence variation of LUX in a range of wheat germplasm. We observed a higher variation in the LUX sequence among accessions coming from the warmer climate and a unique in-frame mutation in early-flowering Chinese T. turgidum cultivar 'Tsing Hua no. 559.' Our results emphasize the importance of the circadian clock in temperate cereals as a promising target for adaptation to new environments.
功能性生物钟有助于生物体使其发育与每日和季节性变化同步，从而从进化适应性和农业角度提供优势。一种结合突变分析的高分辨率图谱方法揭示，一种拟南芥LUX ARRHYTHMO/PHYTOCLOCK 1（LUX/PCL1）的谷类直系同源基因是一粒小麦（Triticum monococcum L.）中早熟基因3（Eps - 3A(m)）位点的一个有前景的候选基因。通过延迟荧光测量表明，含有Eps - 3A(m)的一粒小麦种质KT3 - 5具有扭曲的生物钟。随后通过对核心和输出生物钟基因进行时间进程研究证实了这一假设，该研究表明在恒定环境条件下，即恒定光照和温度下，KT3 - 5中的转录本模式无节律。还证明了野生型和突变体之间小穗数的差异对温度敏感，在25°时差异可忽略不计。这些观察结果使我们提出，扭曲的生物钟是早花以及穗大小和小穗数变化的原因，并且在温暖气候下，LUX功能失调可能具有中性甚至积极的影响。为了验证后一个假设，我们确定了一系列小麦种质中LUX的序列变异。我们观察到来自温暖气候的种质之间LUX序列的变异更高，并且在早熟的中国硬粒小麦品种‘清华559’中存在一个独特的框内突变。我们的结果强调了生物钟在温带谷类中作为适应新环境的一个有前景目标的重要性。
