Genetic regulation of early leaf development in rice

Abstract

Summary: Rice leaf is strap-shaped but shows a complicated structure polarized along the three leaf axes. Leaf shape of grass is roughly determined during the process of leaf founder cell recruitment in the shoot apical meristem(SAM). Accordingly, to elucidate the mechanism of leaf founder cell determination in the SAM is important for a better understanding of leaf development in grass. shoot organization(sho)mutants produce thread-like leaves in the early vegetative phase. The expression pattern of OSHI, a marker of indeterminate cells in the SAM, revealed that a large number of leaf founder cells exits in sho SAM despite the production of narrow leaves. In addition, the variety of leaf phenotype in sho leaves is caused by an unsynchronous growth among leaf domains along the central-marginal axes, suggesting these domains are regulated independently. The phenotypes of sho are very similar to those of weak shootless(shl)mutants showing shoot-less phenotype in the embryo. It is considered that both SHO and SHL genes are important regulators for SAM maintenance and early leaf development in rice.