Discovery Identifies Elaborate G-protein Network in Plants

Discovery Identifies Elaborate G-protein Network in Plants

Key finding has the potential to improve crops’ response to drought, disease and other stresses



ST. LOUIS, MO, April 20, 2011— The most elaborate heterotrimeric G-protein network known to date in the plant kingdom has been identified by Dr. Sona Pandey, principal investigator at the Danforth Plant Science Center.  The results of this research are published in the recent article, "An elaborate heterotirmeric G-protein family from soybean expands the diversity of G-protein networks," in the New Phytologist.



G-proteins are signaling proteins that direct a plant’s response to various environmental signals including abiotic and biotic stresses such as drought and disease resistance.   Prior to Dr. Pandey’s discovery, it was assumed that plants had only one Ga protein based on previous research using Arabidopsis and rice, in contrast to 23 Ga proteins present in humans.   Using soybean, Dr. Pandey’s group was able to identify four Ga proteins.  In addition, they demonstrated that two of these proteins can react faster than was previously assumed.



Mammals have many G-proteins.  These proteins bind GTP (small molecules) and hydrolyze it to GDP.  The G-proteins are active only when GTP bound.   Binding is a key process because that is when the signaling can occur.  Mammals’ G-proteins are very quick to hydrolyze bound GTP and thus cycle fast between the GDP bound and GTP bound states.  The sole Ga protein of the model plant Arabidopsis is very slow to hydrolyze bound GTP.  In this research Dr. Pandey’s group also demonstrated that soybean has two types of G-proteins, two that hydrolyze GTP slowly and two that work more quickly similar to those found in mammals.



“The next step will be to try and engineer plants to express altered amounts of these G-proteins to see how they affect their overall growth and can enable them to better respond to stresses that may be involved in limiting crop yield,” Pandey said.



Signaling mechanism of Heterotrimeric G-protein



About The Donald Danforth Plant Science Center

Founded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a mission to improve the human condition through plant science. Research at the Danforth Center will feed the hungry and improve human health, preserve and renew the environment, and enhance the St. Louis region and Missouri as a world center for plant science. The Center’s work is funded through competitive grants and contract revenue from many sources, including the National Institutes of Health, U.S. Department of Energy, National Science Foundation, U.S. Department of Agriculture, U.S. Agency for International Development and the Bill & Melinda Gates Foundation.

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