A research group led by Dr Yi-Fang Tsay, a Research Fellow conducted by Dr. Cheng-Hsun Ho at the Institute of Molecular Biology, later becoming a Ph.D student jointly sponsored by Academia Sinica’s Taiwan International Graduate Program (TIGP) and the National Defense Medical Center, discovered how changes in soil nutrients are detected by plants. The research, which sheds light on a 20-year-old mystery, was published in the scientific journal "Cell" on September 18 — the first time a botany paper composed entirely by domestic scientists has been published in this prestigious journal.

As plants use roots to acquire all of their essential nutrients from soil in inorganic forms, if soil conditions are not optimal, plants cannot move to a new location. Therefore, to survive and sustain vigorous growth, plants need to have versatile sensing systems to detect and compete for limited soil nutrients. Up until now, however, how plants sense changes in nutrient concentrations, was not understood.

The research team found that plants use a transporter involved in acquiring nitrate from soil to sense nitrate. This is the first ion sensor identified in higher plants. Most sensors identified so far are only able to detect the presence or absence of a substrate. However, this study revealed that the nitrate sensor, CHL1, can detect a wide range of concentration changes and lead to different levels of response in the plant.   

In the future, the sensing mechanism revealed in this study may help to reduce the requirement for nitrogen fertilizer. Moreover, the mechanism may serve as a prototype to understand how nutrient concentration changes are detected in other organisms. Many human diseases such as diabetes are caused by defects of sensing substrate concentration changes and keeping homeostasis. Therefore, the findings of this research may help to understand how the key molecules in the human body are detected and maintain balance. 

The research result also marks a further success for the Taiwan International Graduate Program (TIGP), as Dr. Ho, the first author of the paper was a student of the program when he conducted the research. He has since graduated. The TIGP Ph.D. program is administered by Academia Sinica in cooperation with Taiwan's top universities. TIGP currently consists of nine interdisciplinary Ph. D. programs and has around 320 students. Approximately 56% of TIGP's students come from Taiwan and the other 44% come from 32 countries around the world.

The 2008 impact factor of Cell was 31.253.

The research article entitled: " CHL1 functions as a nitrate sensor in plants" can be found in Volume 138 of "Cell" available at: http://www.cell.com/