Development of Rice Leaves: How Histocytes Modulate Leaf Polarity Establishment

An ideal leaf shape is beneficial to the yield of rice. Molecular understanding of the leaf primordia and polarity establishment plays a significant role in exploring the genetic regulatory network of leaf morphogenesis. In recent years, researchers have cloned an array of coding genes and a few non-coding small RNAs involved in rice leaf development through regulating the development of leaf primordia, vascular bundles, sclerenchyma cells, bulliform cells, cell walls and epidermis cells. These genes and their interactions play critical roles in rice leaf development through the determination and regulatory role in gene expression, and their coordination with other genetic networks or signal pathways. But the relationship among these genes is poorly defined and the underlying network is still unclear. In this review, we introduced the regulatory pathways of leaf primordium development and leaf polarity establishment, mainly the relationship between cell development mechanism and leaf polarity establishment, focusing on how leaf tissue affects leaf shape. Hopefully, the regulation network reviewed here has immediate implications for future research and genomic design breeding.