Heterotrimeric G-Protein Interactions Are Conserved Despite Regulatory Element Loss in Some Plants.

Heterotrimeric G-proteins are key modulators of multiple signaling and development pathways in plants and regulate many agronomic traits, including architecture and grain yield. Regulator of G-protein signaling (RGS) proteins are an integral part of the G-protein networks; however, these are lost in many monocots. To assess if the loss of RGS in specific plants has resulted in altered G-protein networks and the extent to which RGS function is conserved across contrasting monocots, we explored G-protein-dependent developmental pathways in and , representing species without or with a native RGS, respectively. Artificial microRNA-based suppression of in both species resulted in similar phenotypes. Moreover, overexpression of in resulted in phenotypes similar to the suppression of This effect of overexpression depended on its ability to deactivate Gα, as overexpression of a biochemically inactive variant protein resulted in plants indistinguishable from the wild type. Comparative transcriptome analysis of plants with suppressed levels of or overexpression of showed significant overlap of differentially regulated genes, corroborating the phenotypic data. These results suggest that despite the loss of in many monocots, the G-protein functional networks are maintained, and Gα proteins have retained their ability to be deactivated by RGS.