Identification of the Teopod1, Teopod2, and Early Phase Change genes in maize.

Teopod1(Tp1), Teopod2(Tp2), and Early Phase Change (Epc) have profound effects on the timing of vegetative phase change in maize. Gain-of-function mutations in Tp1 and Tp2 delay all known phase-specific vegetative traits, whereas loss-of-function mutations in Epc accelerate vegetative phase and cause shoot abortion in some genetic backgrounds. Here we show that that Tp1 and Tp2 likely represent cis-acting mutations that cause the over-expression of, respectively, Zma-miR156j and Zma-miR156h. Epc is the maize orthologue of HASTY, an Arabidopsis gene that stabilizes miRNAs and promotes their intracellular movement. Consistent with its pleotropic phenotype and epistatic interaction with Tp1 and Tp2, epc reduces the level of miR156 and several other miRNAs.