QQS orphan gene regulates carbon and nitrogen partitioning across species via NF-YC interactions

Each species contains a subset of genes that are uniquely present in that species; the functions and origins of the vast majority of these "orphan genes" are not well-understood. Expression of the Arabidopsis QQS (Qua-Quine Starch; At3g30720) orphan transgene increases the level of protein in soybean lines with high and low protein and acts across flowering plants to increase the protein content of maize and rice. Our results begin to dissect the mechanism of QQS functions by identifying that it binds to the conserved transcription factor nuclear factor Y, subunit C4 (NF-YC4). Increased expression of NF-YC4 in Arabidopsis mimics the effects of increased expression of QQS. The ability to optimize protein productivity in plant-based foods would have far-ranging impacts on world health and sustainability.