The diterpenoid phytohormone gibberellin (GA) controls diverse developmental processes in plants. DELLA proteins are nuclear transcriptional regulators, which function as master growth repressors by inhibiting all aspects of GA responses. Binding of GA to its nuclear receptor GID1 (for GA INSENSITIVE DWARF1) enhances the GID1-DELLA interaction, which in turn leads to the rapid proteolysis of DELLA through the ubiquitin-proteasome pathway, and allows transcriptional reprogramming of GA-responsive genes. This GA- GID1-DELLA signaling module appears to control plant growth and development by integrating internal signals from other hormone pathways [auxin, abscisic acid, jasmonic acid (JA) and ethylene], and external biotic (pathogen) and abiotic cues (light conditions, cold and salt stresses). Recent studies in Arabidopsis show that DELLA directly binds to and regulates key transcription factors/regulators in several signaling pathways (light, JA and developmental pathways). Importantly, these DELLA interactors belong to three different families of transcription factors. However, the current knowledge on how DELLA functions to regulate plant growth is only the tip of the iceberg. The goals of this proposal are to elucidate novel functions of selected newly identified DELLA interactors in GA-modulated plant development by genetic and biochemical approaches, and to determine how DELLA binds to multiple classes of interacting proteins at the molecular level by structure analyses. In addition to transcription factors, some of the new DELLA interactors are chromatin modification proteins, or O-GlcNAc transferase (OGT). O-GlcNAcylation of target proteins by OGT regulates a myriad of cellular pathways in animals, but its function in plants is poorly understood. This study will shed light on how OGT regulates signaling pathways in plants. The proposed study on the DELLA and its interacting regulatory proteins will contribute significantly to the mechanism by which DELLA modulates plant growth. This study will also provide new insights into the mechanisms that modulate transcriptional reprogramming and chromatin structure during growth and development, which are a common theme in controlling cell differentiation and tumorigenesis in humans.

Public Health Relevance

Abnormal cell proliferation of Cancer is often caused by defects in regulating proper gene expression. The proposed study will provide new insights into the regulatory mechanisms that control gene expression to manipulate cell growth and differentiation.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM100051-03
Application #
8666654
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Maas, Stefan
Project Start
2012-08-01
Project End
2016-05-31
Budget Start
2014-06-01
Budget End
2015-05-31
Support Year
3
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Duke University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
City
Durham
State
NC
Country
United States
Zip Code
27705
Hu, Jianhong; Israeli, Alon; Ori, Naomi et al. (2018) The Interaction between DELLA and ARF/IAA Mediates Crosstalk between Gibberellin and Auxin Signaling to Control Fruit Initiation in Tomato. Plant Cell 30:1710-1728
Park, Jeongmoo; Oh, Dong-Ha; Dassanayake, Maheshi et al. (2017) Gibberellin Signaling Requires Chromatin Remodeler PICKLE to Promote Vegetative Growth and Phase Transitions. Plant Physiol 173:1463-1474
Hirano, Yoshinori; Nakagawa, Masahiro; Suyama, Tomoe et al. (2017) Structure of the SHR-SCR heterodimer bound to the BIRD/IDD transcriptional factor JKD. Nat Plants 3:17010
Zentella, Rodolfo; Sui, Ning; Barnhill, Benjamin et al. (2017) The Arabidopsis O-fucosyltransferase SPINDLY activates nuclear growth repressor DELLA. Nat Chem Biol 13:479-485
Zhou, Xin; Zhang, Zhong-Lin; Park, Jeongmoo et al. (2016) The ERF11 Transcription Factor Promotes Internode Elongation by Activating Gibberellin Biosynthesis and Signaling. Plant Physiol 171:2760-70
Zentella, Rodolfo; Hu, Jianhong; Hsieh, Wen-Ping et al. (2016) O-GlcNAcylation of master growth repressor DELLA by SECRET AGENT modulates multiple signaling pathways in Arabidopsis. Genes Dev 30:164-76
Gallego-Giraldo, Carolina; Hu, Jianhong; Urbez, Cristina et al. (2014) Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis. Plant J 79:1020-1032
Sun, Tai-ping (2014) Plant Science. Sex and the single fern. Science 346:423-4
Dayan, Jonathan; Voronin, Nickolay; Gong, Fan et al. (2012) Leaf-induced gibberellin signaling is essential for internode elongation, cambial activity, and fiber differentiation in tobacco stems. Plant Cell 24:66-79
Chapman, Elisabeth J; Greenham, Kathleen; Castillejo, Cristina et al. (2012) Hypocotyl transcriptome reveals auxin regulation of growth-promoting genes through GA-dependent and -independent pathways. PLoS One 7:e36210

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