Plays as a Time Regulator of Leaf Growth via Auxin Signaling.

The growth of leaves is subject to strict time regulation. Several genes influencing leaf growth have been identified, but little is known about how genes regulate the orderly initiation and growth of leaves. Here, we demonstrate that contributes to a time regulation mechanism in leaves from initiation to expansion. encodes the cytochrome P450 CYP78A5, and its homolog has been described whose deletion is detrimental to organ growth. Our results show that overexpression increases leaf size and biomass by altering the time of leaf initiation and expansion. -overexpressing plants have larger leaves with more cells. Further dynamic observations indicate that enlarged wheat leaves have experienced a longer expansion time. Different from inactivation increases leaf number and initiation rates, overexpression only smooths the fluctuations of leaf initiation rates by adjusting the initiation time of local leaves, without affecting the overall leaf number and initiation rates. In addition, complementary analyses suggest is functionally conserved with in controlling the leaf initiation and size and may involve auxin accumulation. Our results provide a new insight into the time regulation mechanisms of leaf growth in wheat.