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Phone: 208-885-5464 Fax: 208-885-6518 Email:zhong@uidaho.edu Ph.D. in Biochemistry RESEARCH INTERESTS: Plant Reproduction Biology; Regulation of Callose Synthesis during Pollen Formation
RESEARCH SUMMARY: Formation of viable pollens is essential for sexual reproduction of flowering plants, and vital to grain production in agriculture. During pollen formation, a callose wall is built on the pollen mother cells and microspore tetrads. This temporary wall provides a physical barrier that helps prevent premature swelling and bursting of the microspores. The callose wall is degraded by beta-1,3-glucanase (callase) secreted by the tapetum cells, leading to the release of microspores in the locular space of developing anthers. Screens of Arabidopsis mutants defective in the callose wall have identified a group of genes required for the formation of viable pollens. Research in my laboratory focuses on the characterization of callose synthase 5 (CalS5) that is responsible for the synthesis of callose during pollen development and pollen tube growth. We intend to identify and characterize new components of the CalS5 complex from developing flowers. The experimental approach taken in my laboratory includes biochemistry, molecular biology, cell and developmental biology, genetics, genomics and proteomics. These studies may lead to the identification of novel protein kinases, small and large GTPases, proteases and other proteins that regulate callose synthesis during gametogenesis and embryogenesis in plants.
REPRESENTATIVE PUBLICATIONS: Dong X, Hong Z, Sivaramakrishnan M, Mahfouz M, Verma DPS (2005) Callose synthase (CalS5) is required for exine formation during microgametogenesis and for pollen viability in Arabidopsis. Plant J. 42: 315-328 Verma DPS, Hong Z (2005) The ins and outs in membrane dynamics: Tubulation and vesiculation. Trends Plant Sci. 10: 159-165. Hong Z, Bednarek S, Blumwald E, Hwang I, Jurgens G, Menzel D, Osteryoung K, Raikhel N, Shinozaki K, Tsutsumi N, Verma DPS (2003) A unified nomenclature for Arabidopsis dynamin-related large GTPases based on homology and possible functions. Plant Mol. Biol. 53: 261-265. Hong Z, Geisler-Lee J, Zhang Z, Verma DPS (2003) Phragmoplastin dynamics: multiple forms, microtubule association and their roles in cell plate formation in plants. Plant Mol. Biol. 53: 297-312. (including the Cover Picture of the Journal) Geisler-Lee J, Hong Z, Verma DPS (2002) Overexpression of the cell plate-associated dynamin-like GTPase, phragmoplastin, results in the accumulation of callose at the cell plate and arrest of plant growth. Plant Sci. 163: 33-42. Verma DPS, Hong Z (2001) Plant callose synthase complexes. Plant Mol. Biol. 47: 693-701. Hong Z, Delauney AJ, Verma DPS (2001) A cell plate-specific callose synthase and its interaction with phragmoplastin and UDP-glucose transferase. Plant Cell 13: 755-768 Hong Z, Zhang Z, Olson J, Verma DPS (2001) A novel UDP glucose
transferase interacts with callose synthase and phragmoplastin
at the forming cell plate. Plant Cell 13, 769-780
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