STUNTEDmediates the control of cell proliferation by GA inArabidopsis

Abstract

Gibberellins (GA) are an important family of plant growth regulators, which are essential for many aspects of plant growth and development. In the GA signaling pathway, the action of GA is opposed by a group of DELLA family repressors, such as RGA. Although the mechanisms of action of the DELLA proteins have been studied in great detail, the effectors that act downstream of DELLA proteins and bring about GA-responsive growth and development remain largely unknown. In this study, we have characterized STUNTED (STU), a receptor-like cytoplasmic kinase (RLCK) VI family gene, which is ubiquitously detectable in all the tissues examined. RGA activity and GA signaling specifically mediate the levels of STU transcripts in shoot apices that contain actively dividing cells. stu-1 loss-of-function mutants exhibit retarded growth in many aspects of plant development. During the vegetative phase, stu-1 seedlings develop smaller leaves and shorter roots than wild-type seedlings, while during the reproductive phase, stu-1 exhibits delayed floral transition and lower fertility. The reduced stature of stu-1 partly results from a reduction in cell proliferation. Furthermore, we present evidence that STU serves as an important regulator mediating the control of cell proliferation by GA possibly through two cyclin-dependent kinase inhibitors, SIM and SMR1. Taken together, our results suggest that STU acts downstream of RGA and promotes cell proliferation in the GA pathway.

Nuclear factor Y-mediated H3K27me3 demethylation of the SOC1 locus orchestrates flowering responses of Arabidopsis

“…These results and the observation on the interactions among these NF-Y subunits suggest that three different types of subunits form the heterotrimeric NF-Y complex that recognizes the same binding region in the SOC1 promoter. We further tested whether CO and RGA also bind to SOC1 by ChIP analysis of SUC2:CO-6HA and ga1-3 gai-t6 rgl1-1 rgl2-1 rga-t2 35S:RGA-6HA 37 . Association of CO-6HA with SOC1 spanned a B1.7 kb promoter region from SOC1-1 to SOC1-9 fragments with an enrichment peak at around SOC1-7 (Fig.…”

Strigolactones Stimulate Internode Elongation Independently of Gibberellins

“…5; Achard et al, 2009;Lee et al, 2012). In pea, the length of epidermal cells in the internode is similar between rms1 SL-deficient mutant plants and wild-type plants.…”

Characterization of dwarf mutants and molecular mapping of a dwarf locus in soybean

“…Plant height depends on both cell division and cell expansion of the stem. Except GA and BR, IAA is also involved in regulation of stem elongation (Achard et al 2009;Lee et al 2012;de Saint et al 2013). GA promotes cell elongation by accelerating the degradation of nuclear DELLAs (Swain and Olszewski 1996;Silverstone et al 2001;Olszewski et al 2002;Achard et al 2009).…”