RT Journal Article
SR Electronic
T1 Plant G Proteins, Phytohormones, and Plasticity: Three Questions and a Speculation
JF Science's STKE
JO Sci. STKE
FD American Association for the Advancement of Science
SP re20
OP re20
DO 10.1126/stke.2642004re20
VO 2004
IS 264
A1 Assmann, Sarah M.
YR 2004
UL http://stke.sciencemag.org/content/2004/264/re20.abstract
AB Heterotrimeric guanine nucleotide-binding proteins (G proteins) composed of Gα, Gβ, and Gγ subunits are important transducers of hormonal signals in organisms as evolutionarily distant as plants and humans. The genomes of diploid angiosperms, such as that of the model species Arabidopsis thaliana, encode only single canonical Gα and Gβ subunits, only two identified Gγ subunits, and just one regulator of G protein signaling (RGS) protein. However, a wide range of processes—including seed germination, shoot and root growth, and stomatal regulation—are altered in Arabidopsis and rice plants with mutations in G protein components. Such mutants exhibit altered responsiveness to a number of plant hormones, including gibberellins, brassinosteroids, abscisic acid, and auxin. This review describes possible mechanisms by which such pleiotropic effects are generated and considers possible explanations for why G protein component mutations in plants fail to be lethal. A possible role of G protein signaling in the control of phenotypic plasticity, a hallmark of plant growth, is also discussed.