Dazhong (Dave) Zhao Assistant Professor B.S. Huazhong Agricultural University, China Ph.D. Institute of Botany, The Chinese Academy of Sciences, China Postdoctoral Fellow Peking University, China The Pennsylvania State University, University Park	Office: Lapham 462 Phone: 414-229-4316 FAX: 414-229-3926 Email: dzhao@uwm.edu Electronic Reserve Materials:
Plant Molecular Genetics and Signal Transduction

Research Interests

Communication between cells is an important process needed by all living organisms for reproduction, development and maintenance of specific cell types. Plant sexual reproduction entails complex developmental processes and provides many opportunities to elucidate both fundamental and plant-specific principles, particularly in cell-cell communication and cell patterning. Research in our laboratory employs a combination of molecular genetic, cell biological, genomic and proteomic approaches to probe the molecular mechanism of cell signaling during anther development in model plant Arabidopsis thaliana. The life cycle of flowering plants alternates between the diploid sporophyte and haploid gametophyte generations. In flowering plants, the pollen (male gametophytes) develops in anther where cell division, differentiation, and subsequent degeneration are essential for successful reproduction. Structurally, an anther has four lobes. Each lobe consists of highly specialized reproductive and non-reproductive cells. The reproductive cells are called microsporocytes (pollen mother cells) that undergo meiosis and, in turn, develop into pollen. Non-reproductive or somatic cells, including epidermis, endothecium, middle layer and tapetum, are required for the normal development and release of pollen. Furthermore, the interaction between the microsporocyte and tapetal cell is essential for pollen development. The anther, therefore, represents an excellent system to study cell signaling and patterning in plants. In addition to the basic mechanism, our research will also impact biological applications in agriculture. Recently, we found that the Arabidopsis EMS1 gene controls the fate determination of a non-reproductive cell type (tapetal cells), which is necessary for pollen development. EMS1 encodes a signaling molecule that belongs to the family of leucine-rich repeat receptor-like protein kinases (LRR-RLK) with 216 members in Arabidopsis. Our current emphasis is to address how the EMS1-dependent signal transduction pathway is involved in regulating anther cell differentiation. Our lab is also interested in analyzing genes controlling flower development and meiosis using molecular and genetic techniques. We always welcome collaborations at various levels as well as researchers, including undergraduate and graduate students, postdocs and visiting scholars, to join our lab or learn more about our research.

Selected Publications

Ni, W., Xie, D., Hobbie, L., Feng, B., Zhao, D., Akkara, J. and Ma, H. 2004. Regulation of flower development in Arabidopsis by SCF complex. Plant Physiology 134:1574-1585. Zhao, D., Han, T., Risseeuw, E., Crosby, W.L. and Ma, H. 2003. Conservation and divergence of ASK1 and ASK2 gene functions during male meiosis in Arabidopis. Plant Molecular Biology 53: 163-173. Zhao, D.,* Ni, W.,* Feng, B., Han, T., Petrasek, M. and Ma, H. 2003. Members of the Arabidopsis-SKP1-like gene family exhibit a variety of expression patterns and may play diverse roles in Arabidopsis. Plant Physiology 133: 203-217. (*equal contribution) Zhao, D., Wang, G., Speal, B. and Ma, H. 2002. The EXCESS MICROSPOROCYTES1 gene encodes a putative leucine-rich repeat receptor protein kinase that controls somatic and reproductive cell fates in the Arabidopsis anther. Genes & Development 16: 2021-2031. Azumi, Y., Liu, D., Zhao, D., Li, W., Wang, G., Hu, Y. and Ma, H. 2002. Homologue interaction during meiotic prophase I in Arabidopsis requires the SOLO DANCERS encoding a novel cyclin-like protein. EMBO J. 21: 3081-3095. Zhao, D., Yu, Q., Chen, M. and Ma, H. 2001. The ASK1 gene regulates B function gene expression in co-operation with UFO and LEAFY in Arabidopsis. Development 128: 2735-2746. Zhao, D., Yu, Q., Chen, C. and Ma, H. 2001. Genetic control of reproductive meristems. In: Meristematic Tissues in Plant Growth and Development. (Eds. McManus, M. T. and Veit, B.) Sheffield Academic Press, Sheffield, England. (Invited chapter), pp. 89-142. Zhao, D. and Ma, H. 2000. Male fertility: a case of enzyme identity. Current Biology 10: R904-907. Zhao, D., Yang, M., Solava, J. and Ma, H. 1999. The ASK1 gene regulates development and interacts with the UFO gene to control floral organ identity in Arabidopsis. Developmental Genetics 25: 209-223.