Photosynthesis and Photobiology Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Japan.
Plant Cell. 2011 May;23(5):1741-55. doi: 10.1105/tpc.111.083238. Epub 2011 May 13.
The circadian clock controls physiological traits such as flowering time, photosynthesis, and growth in plants under laboratory conditions. Under natural field conditions, however, little is known about the significance of the circadian clock in plants. By time-course transcriptome analyses of rice (Oryza sativa) leaves, using a newly isolated rice circadian clock-related mutant carrying a null mutation in Os-GIGANTEA (Os-GI), we show here that Os-GI controlled 75% (false discovery rate = 0.05) of genes among 27,201 genes tested and was required for strong amplitudes and fine-tuning of the diurnal rhythm phases of global gene expression in the field. However, transcripts involved in primary metabolism were not greatly affected by osgi. Time-course metabolome analyses of leaves revealed no trends of change in primary metabolites in osgi plants, and net photosynthetic rates and grain yields were not affected. By contrast, some transcripts and metabolites in the phenylpropanoid metabolite pathway were consistently affected. Thus, net primary assimilation of rice was still robust in the face of such osgi mutation-related circadian clock defects in the field, unlike the case with defects caused by Arabidopsis thaliana toc1 and ztl mutations in the laboratory.
生物钟控制着植物的生理特征，如开花时间、光合作用和生长，在实验室条件下。然而，在自然野外条件下，人们对生物钟在植物中的重要性知之甚少。通过对水稻（Oryza sativa）叶片进行时间过程转录组分析，利用一种新分离的携带 Os-GIGANTEA（Os-GI）缺失突变的水稻生物钟相关突变体，我们在这里表明，Os-GI 控制了 27201 个测试基因中的 75%（错误发现率=0.05），并且是在野外控制全球基因表达的昼夜节律相位的强幅度和微调所必需的。然而，参与初级代谢的转录物不受 osgi 的影响。叶片的时间过程代谢组学分析显示，osgi 植物中初级代谢物没有明显的变化趋势，净光合速率和籽粒产量不受影响。相比之下，苯丙烷代谢物途径中的一些转录物和代谢物受到持续影响。因此，与实验室中拟南芥 toc1 和 ztl 突变引起的缺陷相比，在野外，即使存在这种与生物钟缺陷相关的 osgi 突变，水稻的净初级同化仍然很强。
