Antagonistic genes control rice growth
A plant steroid prompts two genes to battle against each other - one suppresses the other to ensure that leaves are grown in a normal manner in rice and the experimental plant Arabidopsis thaliana, which is a relative of mustard, as per scientists at the Carnegie Institution.
The results appeared in the December 15, 2009, issue of The Plant Cell and are believed to have important implications for understanding as to how crop growth and yield may be manipulated.
From Sciencedaily.com:
Co-author Zhi-Yong Wang at Carnegie’s Department of Plant Biology explained the work: “We knew that the steroid is very important for activating genes that control cell growth in Arabidopsis as well as in rice. One of the most sensitive responses to the steroid is leaf bending in rice, caused by expansion of the upper cells at the joint between leaf blade and leaf sheath. We wanted to determine how the steroid functioned in rice. We found that the steroid affects two genes encoding (or producing) proteins that turn other genes on or off; they are called transcription factors. In rice, when a gene called Increased Leaf Inclination1 (ILI1) is turned on, it causes leaf bending. Interestingly, we found that the ILI1 protein also binds to another transcription factor, called IBH1, and inhibits its function. When there is too much ILI1 protein, the leaves bend excessively making the plant shaggy. When IBH1 level is high, cell growth is stopped at the joint and the rice is very erect, taking up less space. In normal rice plants the balance between ILI1 and IBH1 keeps growth in check.”
This pair of genes provides a unique tool to control the leaf angle, which is important for crop yield because erect leaves improve light capture and allows rice plants to be planted at higher density for a higher yield per hectare.
The study colleagues were from the following institutions: Institute of Botany, Chinese Academy of Sciences; Chinese Academy of Agricultural Sciences; Department of Plant Biology, Carnegie Institution; Yonsei University, Korea; RIKEN Advanced Science Institute, Japan.
