Haiyang Wang

Assistant Scientist

Office/Lab: Room 229/224

Contact: hw75@cornell.edu / 607-254-7476

Affiliations:

Adjunct Assistant Professor in Cornell University’s

Department of Plant Biology

Graduate Field: Plant Biology; Genetics and Development

Research Summary

Light is a major environmental signal that regulates many aspects of plant growth and development, ranging from seed germination, to seedling de-etiolation, gravitropism and phototropism, chloroplast movement, shade avoidance, circadian rhythms, and flowering time—all traits with practical implications for agriculture. Phytochromes are photoreceptors that perceive red and far-red light, and they regulate plant growth and development through the activation of distinct signal transduction pathways. My primary research interest is to understand the molecular, cellular and biochemical mechanisms regulating plant response to light, using Arabidopsis seedling photomorphogenesis as a model system (Figure 1). My research utilizes a combinatorial approach, including forward and reverse genetics, genomics, molecular biology, biochemistry, cell biology and bioinformatics. One project in the lab is focused on elucidating the transcriptional regulatory network regulating phytochrome A (phyA, the primary photoreceptor for far-red light) signaling in Arabidopsis. Our recent work showed that Arabidopsis FHY3 and FAR1, which encode two proteins related to Mutator-like transposases, act together to modulate phyA signaling by directly activating the transcription of FHY1 and FHL, which in turn is essential for light-induced phyA nuclear accumulation and subsequent light responses. Further, expression of FHY3 and FAR1 is negatively regulated by phyA signaling, which means that FHY3 and FAR1 also act at the nexus of a negative feedback loop to regulate the homeostasis of phyA signaling. Our results suggest that FHY3 and FAR1 represent transcription factors that have been co-opted from an ancient transposase to regulate light signaling in higher plants.

Figure 1. The contrasting phenotypes of dark vs. light-grown Arabidopsis seedlings.

With this research project, we are currently pursuing the following research activities: 1.) Identification and functional analysis of the global target genes of FHY3 and FAR1; 2.) Functional analysis of FHY3 protein complex and FHY3-interacting proteins; 3.) The role of FHY3 and FAR1 in circadian clock regulation; 4.) Functional analysis of other FHY3/FAR1-like genes in Arabidopsis. In addition, we are also interested in exploring whether the transcriptional regulatory network composed of FHY3, FAR1, FHY1 and FHL is evolutionarily conserved in other angiosperms, particularly agricultural plants (such as poplar tree and rice), to regulate phytochrome nuclear import. This research project is currently supported by the National Science Foundation (IOS-0641639).

A second research area in my lab is focused on posttranslational regulation of light signaling in Arabidopsis. Regulated protein degradation by the 26S proteasome is vital for cellular signaling regulation, as essential to the cell as protein synthesis. Our previous work has shown that HFR1, a bHLH transcription factor, defines a key regulator of seedling photomorphogenesis and shade avoidance response in Arabidopsis. We showed that in darkness, HFR1 protein is targeted for 26S proteasome-mediated degradation by the COP1-SPA1 E3 ubiquitin ligase complex, and is rapidly stabilized by light to promote light responses. We are also study the role of phosphorylation in regulating HFR1 stability and its signaling activity. We have identified the putative kinase and phosphatase that are likely responsible for reversible phosphorylation of HFR1. Current research is directed towards: 1.) Functional analysis of the putative kinase and phosphatase in regulating HFR1 stability, protein-protein interaction and function; 2.) Functional analysis of additional HFR1-interacting proteins; 3.) Identification and functional characterization of HFR1 downstream target genes. This research project is supported by the National Science Foundation (MCB-0749606).

Publications

View Publications

Lin, R., H. Wang. 2007. Targeting proteins for degradation by Arabidopsis COP1: Teamwork is what matters. J. of Integrative Plant Biology 49(1): 35-42
Lin, R., Ding, L., Casola, C., Ripoll, D., Feschotte, C., and Wang, H. 2007. Transposase-derived transcription factors regulate light signaling in Arabidopsis. Science 318: 1302-1305
Garg, A. K., R. J. Sawers, H. Wang, J. K. Kim, J. M. Walker, T. P. Brutnell, M. V. Parthasarathy, R. D. Vierstra, R. J. Wu. 2006. Light-regulated Overexpression of an Arabidopsis Phytochrome A Gene in Rice Alters Plant Architecture and Increases Grain Yield. Planta 223: 627-636
Yang, J., H. Wang. 2006. The central coiled-coil domain and carboxyl-terminal WD-repeat domain of Arabidopsis SPA1 are responsible for mediating repressing of light signaling. Plant Journal 47: 564-576
Shen, Y., S. Feng, L. Ma, R. Lin, L. J. Qu, Z. Chen, H. Wang, X. W. Deng. 2005. Arabidopsis FHY1 Protein Stability Is Regulated by Light Via Phytochrome A and 26S Proteasome. Plant Physiology 139(3): 1234-1243
Yang, J., R. Lin, J. Sullivan, U. Hoecker, B. Liu, L. Xu, X. W. Deng, H. Wang. 2005. Light Regulates COP1-mediated Degradation of HFR1, a Transcription Factor Essential for Light Signaling in Arabidopsis. Plant Cell 17(3): 804-821
Yang, J., R. Lin, U. Hoecker, B. Liu, L. Xu, H. Wang. 2005. Repression of Light Signaling by Arabidopsis SPA1 Involves Post-translational Regulation of HFR1 Protein Accumulation. The Plant Journal 43(1): 131-141
Wang, H., . 2005. Signaling Mechanisms of Higher Plant Photoreceptors: A Structure-function Perspective. Current Topics in Developmental Biology 68: 227-61
Lin, R., H. Wang. 2005. Two Homologous ABC Transport Proteins, AtMDR1 and AtPGP1, Regulate Arabidopsis Photomorphogenesis and Root Development By Mediating Polar Auxin Transport. Plant Physiology 138(2): 949-964
Lin, R., H. Wang. 2004. Arabidopsis FHY3/FAR1 Gene Family and Distinct Roles of Its Members in Light Control of Arabidopsis Development. Plant Physiology 136: 4010-4022
Wang, H., X. W. Deng. 2004. Phytochrome Signaling Mechanisms. The Arabidopsis Book :
Wang, H. Y., X. W. Deng. 2003. Dissecting the phytochrome A-dependent signaling network in higher plants. Trends in Plant Science 8(4): 172-178
Saijo, Y., J. A. Sullivan, H. Wang, J. Yang, Y. Shen, V. Rubio, L. Ma, U. Hoecker, X. W. Deng. 2003. The COP1-SPA1 Interaction Defines a Critical Step in Phytochrome A-mediated Regulation of HY5 Activity. Genes & Development 17(21): 2642-2647