Regulation of Leaf Morphology by MicroRNA394 and its Target LEAF CURLING RESPONSIVENESS

Abstract

The present study identified Arabidopsis miR394 and its target, an F-box (SKP1-Cullin/CDC53-F-box) gene At1g27340 (here referred to as LEAF CURLING RESPONSIVENESS, LCR), for regulation of leaf curling-related morphology. The loss-of-function lcr mutants exhibit pleiotropic defects with semi-dwarfism, altered leaf shape and a shorter stem. Overexpression of an miR394-resistant version of LCR under the 35S promoter (35S:m5LCR) and target mimicry MIM394 resulted in a curled-down leaf defect. Conversely, transgenic plants overexpressing 35S:MIR394a/b display a curled-up leaf phenotype. Detailed analyses show that there is a certain level of LCR that is optimal for leaf morphology, but lower or higher levels lead to abnormal leaf development, indicating that expression of miR394 in the leaf lamina is necessary for proper leaf morphology. Because the phytohormone auxin plays a crucial role in leaf morphogenesis and patterning, the DR5-GUS reporter gene was used to monitor the auxin response. We show that DR5 expression patterns in lcr and 35S::m5LCR plants were significantly different from those in the wild type. Also, overexpression of LCR in 35S::m5LCR plants drastically decreased the expression of the auxin-responsive genes IAA3, AXR3 and IAMT1, whereas increased expression of the genes was found in 35S::MIR394a plants. These results indicate that miR394 and its target LCR are involved in the regulation of leaf development.

MicroRNA dynamics in a wild and cultivated species of Convolvulaceae exposed to drought stress

“…by targeting LEAF CURLING RESPONSIVENESS {LCR} gene). It is known to be drought responsive in Arabidopsis and other species (Song et al 2012;Liu et al 2008;Kantar et al 2011;Shuai et al 2013). Upregulation of miR394 in J. pentantha is comparable to those reported in cotton (0.87 fold increase) exposed to drought stress (Xie et al 2014).…”

Transgenic Plants That Express the Phytoplasma Effector SAP11 Show Altered Phosphate Starvation and Defense Responses

“…By contrast, miR172, miR396, miR5020, miR5629, miR5645, and miR5648 showed significant down-regulation in the 35S::SAP11 AYWB transgenic plants. Among them, miR2111, miR399, and miR827 have been shown to be up-regulated by Pi starvation (Hsieh et al, 2009;Pant et al, 2009), and miR399 and miR827 play important roles in regulating Pi homeostasis (Liu et al, 2012;Huang et al, 2013;Lin et al, 2013); miR160 and miR396 are required for regulating the auxin signaling response and cell proliferation during leaf and root development (Gutierrez et al, 2009;Pulido and Laufs, 2010;Debernardi et al, 2012;Bazin et al, 2013); miR172 has been shown to regulate the transition from the vegetative to reproductive phases (Aukerman and Sakai, 2003;Wu et al, 2009); and miR394 is required for the regulation of leaf morphology and shoot meristem stem-cell maintenance (Song et al, 2012;Knauer et al, 2013). However, miR5020b, miR5629, miR5639, miR5645d, miR5648, miR5655, and miR850 are newly identified miRNAs with unknown functions.…”

The dicer-like1 Homolog fuzzy tassel Is Required for the Regulation of Meristem Determinacy in the Inflorescence and Vegetative Growth in Maize

“…In Arabidopsis, miR394 targets the F-box gene LEAF CURLING RESPONSIVENESS and functions as a mobile signal to establish stem cell niche organization (Song et al, 2012;Knauer et al, 2013). In maize, miR394 is predicted to target the F-box genes GRMZM2G119650 and GRMZM2G064954, both of which are broadly expressed during maize development, including in inflorescences (Sekhon et al, 2011).…”