This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 19/10/3037    most recent tpc.107.054999v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in Plant Cell Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zentella, R. Articles by Sun, T.-p. Search for Related Content PubMed PubMed Citation Articles by Zentella, R. Articles by Sun, T.-p. Agricola Articles by Zentella, R. Articles by Sun, T.-p.

Global Analysis of DELLA Direct Targets in Early Gibberellin Signaling in Arabidopsis^[W]

^a Department of Biology, Duke University, Durham, North Carolina 27708
^b RIKEN Plant Science Center, Tsurumi-ku, Yokohama, 230-0045, Japan

⁵ Address correspondence to tps{at}duke.edu.

Bioactive gibberellins (GAs) are phytohormones that regulate growth and development throughout the life cycle of plants. DELLA proteins are conserved growth repressors that modulate all aspects of GA responses. These GA-signaling repressors are nuclear localized and likely function as transcriptional regulators. Recent studies demonstrated that GA, upon binding to its receptor, derepresses its signaling pathway by binding directly to DELLA proteins and targeting them for rapid degradation via the ubiquitin-proteasome pathway. Therefore, elucidating the signaling events immediately downstream of DELLA is key to our understanding of how GA controls plant development. Two sets of microarray studies followed by quantitative RT-PCR analysis allowed us to identify 14 early GA-responsive genes that are also early DELLA-responsive in Arabidopsis thaliana seedlings. Chromatin immunoprecipitation provided evidence for in vivo association of DELLA with promoters of eight of these putative DELLA target genes. Expression of all 14 genes was downregulated by GA and upregulated by DELLA. Our study reveals that DELLA proteins play two important roles in GA signaling: (1) they help establish GA homeostasis by direct feedback regulation on the expression of GA biosynthetic and GA receptor genes, and (2) they promote the expression of downstream negative components that are putative transcription factors/regulators or ubiquitin E2/E3 enzymes. In addition, one of the putative DELLA targets, XERICO, promotes accumulation of abscisic acid (ABA) that antagonizes GA effects. Therefore, DELLA may restrict GA-promoted processes by modulating both GA and ABA pathways.

Related articles in Plant Cell:

GA Signaling: Direct Targets of DELLA Proteins

Nancy A. Eckardt
Plant Cell 2007 19: 2970. [Full Text]  

This article has been cited by other articles:

				D. E. Weston, R. C. Elliott, D. R. Lester, C. Rameau, J. B. Reid, I. C. Murfet, and J. J. Ross The Pea DELLA Proteins LA and CRY Are Important Regulators of Gibberellin Synthesis and Root Growth Plant Physiology, May 1, 2008; 147(1): 199 - 205. [Abstract] [Full Text] [PDF]

				S. Toh, A. Imamura, A. Watanabe, K. Nakabayashi, M. Okamoto, Y. Jikumaru, A. Hanada, Y. Aso, K. Ishiyama, N. Tamura, et al. High Temperature-Induced Abscisic Acid Biosynthesis and Its Role in the Inhibition of Gibberellin Action in Arabidopsis Seeds Plant Physiology, March 1, 2008; 146(3): 1368 - 1385. [Abstract] [Full Text] [PDF]