For flowering plants including crops, one of the most important decisions is when to flower. Knowledge of this process at the cellular level is critical for understanding how plants allocate resources and produce the components of human interest, such as grains and fruits.
In a paper published Sept. 24 in the journal Nature Plants, an international team of researchers has discovered that the geneFT- the primary driver of the transition to flowering in plants each spring - does something unexpected in the model species Arabidopsis thalianaplants grown in natural environments, with implications for the artificial growing conditions scientists commonly use in the lab.
In prior research conducted on Arabidopsisplants grown indoors under fluorescent light only an evening peak of FT gene activity was observed. Dr. Reiko Akiyama and Prof. Dr. Kentaro Shimizu at UZH grew the plants outside in the Strickhof plant garden at the UZH Irchel campus. Dr. Akiyama collected samples every 4 hours throughout an entire day beginning at dawn. Experiments in the field conditions in Zurich were essential to assess the natural plant responses because Zurich is located in the natural distribution range of Arabidopsis. They found that outdoor plants showed morning peak of FT activity and flowered earlier than in the laboratories. The team consists of researchers in Switzerland, Scotland, South Korea, Japan and the USA led by Prof. Dr. Takato Imaizumi at the University of Washington, USA. They concluded that the indoor, artificial growing conditions missed key qualities of natural conditions, throwing off expression of theFTgene and the trait it governs. The data support the importance of the study of gene function in natura, a technical term coined by Prof. Dr. Kentaro Shimizu and colleagues in 2011 to highlight the difference of gene functions in natural complex environments compared with those studied by in vitroand in vivolaboratory experiments.
A series of follow-up experiments identified light and temperature conditions as the source of the differences in the FT gene expressions between indoor and outdoor growing conditions. The red/far-red light ratio of fluorescent light bulbs commonly used in indoorArabidopsisresearch differs from that of the sunlight. Unlike indoors, the temperature fluctuates outdoors. The results illuminate a path forward for plant researchers to adopt artificial growth conditions that more accurately reflect natural growing conditions. The study will be important for crop research as crop species are usually grown outside and flowering time is a major target of breeding.
Young Hun Song, Arkane Kubota, Michael S. Kown, Michael F. Covington, Nayoung Lee, Ella R. Taagen, Dianne Laboy Cintron, Dae Yeon Hwang, Reiko Akiyama, Sarah K. Hodge, He Huang, Nhu H. Nguyen, Dimitri A. Nusinow, Andrew J. Millar, Kentaro K. Shimizu and Takato Imaizumi, Molecular basis of flowering under natural long-day conditions in Arabidopsis, Nature Plants, https://doi.org/10.1038/s41477-018-0253-3
University of Zurich
Prof. Kentaro Shimizu
Institute of Evolutionary Biology and Environmental Studies