Researchers at Paradigm Genetics, Inc. (Nasdaq: PDGM), in collaboration with scientists at the University of North Carolina, Chapel Hill, NC, and The Salk Institute for Biological Sciences, La Jolla, CA, announced the discovery for the first time of the role of heterotrimeric G-protein signaling in plant cell proliferation and its association with key agronomic traits. This discovery will also enable researchers to identify the cell surface receptor associated with the G-proteins that in turn can be manipulated to trigger effects on crop traits.

"This study for the first time reveals important agronomic traits associated with G-protein signaling and opens up a new approach to altering important crop traits such as yield," said Dr. Keith Davis, Vice President, Agricultural Research, who led the Paradigm team.

Heterotrimeric G-proteins, a large class of signaling proteins, and the associated receptors that these proteins interact with, are among the most important targets for drug development in the pharmaceutical industry, accounting for at least $21 billion in drug sales per annum.

Heterotrimeric G-proteins respond to signals from outside the cell--light, chemicals, etc.--through a cell surface associated receptor, and translate (transduce) these signals into action within the cell. While the presence of a single heterotrimeric G-protein complex in plants was suggested based on sequence information alone, their role in plant biology has not been understood.

"While we know a tremendous amount about G-proteins in animals, the role of heterotrimeric Gproteins in plants had largely been overlooked," said Alan Jones, Ph.D., co-author of the paper and a Professor at the University of North Carolina-Chapel Hill. "The use of Paradigm's GeneFunction Factory™ was pivotal in identifying the complex phenotypes and revealing important agronomic traits controlled by the plant G-protein."

A functional heterotrimeric G-protein complex consists of three subunits, alpha, beta and gamma. In this study, homology-modeling studies were first used to compare the structures of known mammalian and yeast subunits to the plant (Arabidopsis) subunits. The genes coding for two of the subunits of the G-protein complex were independently knocked out to create mutant plants lacking a functional complex. These mutants were grown side by side with their corresponding "wild type" plants and numerous features, including many associated with fruit yield, were compared using Paradigm’s phenotypic analysis platform, GeneFunction Factory™. By restricting the knockout only to specific tissues, Paradigm scientists are now able to more easily determine G-protein involvement in key signal transduction pathways associated with cell proliferation and new means to control plant performance and yield.