Rice leaf inclination2, a VIN3-like protein, regulates leaf angle through modulating cell division of the collar

Abstract

As an important agronomic trait, inclination of leaves is crucial for crop architecture and grain yields. To understand the molecular mechanism controlling rice leaf angles, one rice leaf inclination2 (lc2, three alleles) mutant was identified and functionally characterized. Compared to wild-type plants, lc2 mutants have enlarged leaf angles due to increased cell division in the adaxial epidermis of lamina joint. The LC2 gene was isolated through positional cloning, and encodes a vernalization insensitive 3-like protein. Complementary expression of LC2 reversed the enlarged leaf angles of lc2 plants, confirming its role in controlling leaf inclination. LC2 is mainly expressed in the lamina joint during leaf development, and particularly, is induced by the phytohormones abscisic acid, gibberellic acid, auxin, and brassinosteroids. LC2 is localized in the nucleus and defects of LC2 result in altered expression of cell division and hormone-responsive genes, indicating an important role of LC2 in regulating leaf inclination and mediating hormone effects.

The Binding Specificity of the PHD-Finger Domain of VIN3 Moderates Vernalization Response

“…However, their roles in chromatin-modifying activities are largely not known. In particular, the VIN3 family of proteins is conserved throughout higher plants and play roles in diverse developmental programs (Zhao et al, 2010;Wang et al, 2013). Whether the histone binding preference of PHDfinger domains of the VIN3 family of proteins in other plant species functions in a similar manner remains to be addressed.…”

Dynamic Cytology and Transcriptional Regulation of Rice Lamina Joint Development

“…Deficiency of lamina joint structure (Lee et al, 2007), suppressed longitudinal elongation of adaxial parenchyma cells, and increased division of abaxial sclerenchyma cells of the lamina joint (Zhang et al, 2009a;Sun et al, 2015) result in leaf erectness. Conversely, increased expansion or proliferation of adaxial parenchyma cells leads to increased leaf inclination (Zhao et al, 2010(Zhao et al, , 2013Zhang et al, 2015). Abnormal vascular bundle formation and cell wall composition also result in changed leaf angle (Ning et al, 2011).…”

“…INCREASED LEAF ANGLE1 (ILA1) encodes a Raf-like MAPKKK of group C, and the ila1 mutant presents increased leaf angle by abnormal vascular bundle formation and cell wall composition in the lamina joint (Ning et al, 2011). In addition, LEAF IN-CLINATION2 (LC2), a VIN3-like protein, controls leaf inclination by inhibiting adaxial cell division (Zhao et al, 2010). Suppression of small RNA-producing genes, including RNA-dependent RNA polymerase2, RNase III-class Dicer-like3, and OsAGO4a and OsAGO4b (members of the Argonaute family), results in the increased bending of the lamina joint (Wei et al, 2014), while increased expression of OsAGO7 leads to the leaf erectness (Shi et al, 2007).…”

Harnessing Genetic Variation in Leaf Angle to Increase Productivity of Sorghum bicolor

“…More than 40 additional quantitative trait loci (QTL) have been identified in the maize nested association mapping (NAM) and recombinant inbred lines (RIL) populations (McMullen et al 2009;Tian et al 2011;Li et al 2015). In rice, osdwarf4-1 and leaf inclination2 have been identified and shown to play roles in plant hormone responses that result in changes in leaf angle (Sakamoto et al 2006;Zhao et al 2010). Progress in identifying leaf angle QTL has been made in sorghum, the fifth most widely produced grain and forage crop, but a gene that regulates leaf angle has yet to be identified as has been done in maize and rice (Hart et al 2001;Gill et al 2014;Perez et al 2014;Xin et al 2015).…”