Associate Professor of Plant Molecular Biology
Ph.D. Michigan State University
Contact Information
126 Natural Resources
Michigan State University
East Lansing, MI 48824-1222 USA
Office: (517) 353-4751
Laboratory: 353-7968 & 432-6180
Fax: (517) 432-1143
Email: hanky@msu.edu
Related Links
- Genetics Graduate Program
- Plant Breeding and Genetics Graduate Program
- Department of Forestry–College of Agriculture and Natural Resources
- Michigan Agricultural Experiment Station
- Michigan State University
Research Overview
Molecular Biology of Secondary Growth
We developed a novel experimental system to study the molecular regulation of secondary growth (i.e., wood formation) in Arabidopsis thaliana. Using this system, Arabidopsis whole-transcriptome GeneChip analyses have provided an unprecedented view of the flux that occurs in the transciptome during secondary growth. Subsequently, we identified a short list of candidate genes that are likely to be involved in the genetic regulation of secondary growth. Our current research is specifically aimed at determining the functions of the selected genes by experimental manipulation and evaluation, in the context of the whole organism.
Selected publications related to secondary growth
Ko, J.-H., Yang, S., Park, A.H., Lerouxel, O., and Han, K.-H. 2007. ANAC012, a member of the plant-specific NAC transcription factor family, negatively regulates xylary fiber development in Arabidopsis thaliana. Plant J, 50: 1035-1048
Ko, J.-H., Beers, E.P., and Han, K.-H. 2006. Global comparative transcriptome analysis identifies gene network regulating secondary growth in Arabidopsis thaliana. Molecular Genetics and Genomics 276: 517-531.
Ko, J.-H., Kim, J.H., Jayanty, S.S., Howe, G.A., and Han, K.-H. 2006. Loss of function of COBRA, a determinant of oriented cell expansion, invokes cellular defense responses in Arabidopsis thaliana. Journal of Experimental Botany 57: 2923-2936.
Prassinos, C., Ko, J.-H., Yang, J., and Han, K.-H. 2005. Transcriptome profiling of vertical stem segments provides insights into the genetic regulation of secondary growth in hybrid aspen trees. Plant Cell Physiology 46(8): 1213-1225.
Ko, J.H. and Han, K.-H. 2004. Arabidopsis whole-transcriptome profiling defines the features of coordinated regulations that occur during wood formation. Plant Molecular Biology, 55: 433-453.
Ko, J.H., Han, K.-H., Park, S., and Yang, J. 2004. Plant body weight-induced secondary growth in Arabidopsis and its transcription phenotype revealed by whole-transcriptome profiling. Plant Physiology 135: 1069-1083.
Oh, S., Park, S., and Han, K.-H. 2003. Transcriptional regulation of secondary growth in Arabidopsis thaliana. Journal of Experimental Botany 54: 2709-2922
Annual Growth Cycle of Woody Plants
Temperate woody plants have an adaptive mechanism for winter survival, which involves alternation between active shoot growth and vegetative dormancy. This annual growth cycle is closely timed with seasonal changes. Despite its environmental and economic significance, the genes and the regulatory networks controlling this growth cycle remain undiscovered. As the first step toward our long-term goal of achieving a system-level understanding of the complex biology of the annual growth cycle, we take an integrated functional genomics approach to identify candidate genes and determine their functional roles in the annual growth cycles.
Publications related to annual growth cycle
Park, S.C., Keathley, D.E., and Han, K.-H. 2007. Transcriptional profiles of the annual growth cycle in Populus. Tree Physiology, in press
Ko, J.-H., Prassinos, C., and Han, K.-H. 2006. Developmental and seasonal expression of PtaHB1, a Populus gene encoding a class III HD-Zip protein, is tightly associated with secondary growth and inversely correlated with the level of microRNA (miR166). New Phytologist 169: 469-478
Park, S.C., Oh, S., and Han, K.-H. 2004. Large-scale computational analysis of poplar ESTs reveals the repertoire and unique features of expressed genes in poplar genome. Molecular Breeding 14: 429-440.
Bioeconomy
Han, K.-H., Ko, J.-H., and Yang, S.H.. 2007. Functional genomics approach to optimizing lignocellulosic feedstock for improved biofuel productivity and processing. BioFPR 1: 135-146
Ko, J.-H., Yang, S., and Han, K.-H. 2006. Upregulation of an Arabidopsis RING-H2 gene, XERICO, confers drought tolerance through increased ABA biosynthesis. Plant J 47: 343-355.
Heartwood and Its Extractive Formation
In a practical sense, the presence of heartwood is a determining factor for wood quality and influences the utilization of wood in many different ways. Heartwood formation in a living tree is concerned with aging processes that are occurring in spatially and temporally different cells. It is extremely difficult to experimentally observe the complex metabolic changes during the processes that occur in the sapwood. Genomics is a novel technology that can supplement traditional biological methods. It provides a rare opportunity for studying the molecular biology of heartwood and its extractive formation. We have been developing and using various genomics tools including expressed sequence tags, cDNA microarrays, cDNA-AFLP (amplified fragment length polymorphism), enhancer/gene trap analysis, and GeneChip arrays for wood formation studies.
Publications related to heartwood formation
Yang, J. and Han, K.-H. 2004. Functional characterization of allantoinase genes from Arabidopsis and a non-ureide type legume black locust (Robinia pseudoacacia L.). Plant Physiology 134: 1039-1049
Yang, J., Kamdem, D.P., Keathley, D.E., and Han, K.-H. 2004. Seasonal gene expression changes at the sapwood-heartwood transition zone of black locust (Robinia pseudoacacia L.) revealed by cDNA microarray analysis. Tree Physiology 24: 461-474
Yang, J., Park, S., Kamdem, D.P., Keathley, D.E., Retzel, E., Paule, C., Kapur, V. and Han, K.-H. 2003. Novel gene expression profiles define the metabolic and physiological processes characteristic of wood and its extractive formation in a hardwood tree species, Robinia pseudoacacia. Plant Mol. Biol. 52: 935-956.
Biosynthesis of Natural Rubber
Natural rubber, an isoprenoid polymer with no known physiological function to the plant, is produced in about 2000 plant species with varying degrees of quality and quantity. It is made by head-tail condensation of isoprene units derived from isopentenyl diphosphate (IPP). Natural rubber from H. brasileinsis contains some 5,000-10,000 isoprene units exclusively in cis configuration. Several latex proteins showing rubber polymerase-like activity in vitro have been reported, but none of them proved to be rubber polymerase. The genes responsible for the final steps of rubber biosynthesis remain to be identified.
Publications related to rubber biosynthesis
Ko, J.-H., Chow, K.-S., and Han, K.-H. 2004. Transcriptome analysis offers new insights into the biology of laticifers in Hevea brasiliensis (the Para rubber tree). Plant Molecular Biology 53: 479-492.
Oh, S.K., Han, K.-H., Ryu, S.B., and Kang, H. 2000. Molecular cloning, expression, and functional analysis of a plant cis-prenyltransferase from Arabidopsis thaliana. Journal of Biological Chemistry 275: 18482-18488
Kang, H.S., Kang, M.Y., and Han, K.-H. 2000. Identification of natural rubber and characterization of rubber biosynthetic activity in fig tree (Ficus carica). Plant Physiology 123: 1133-1142
Oh, S.K., Shin, D.H., Yang, J.M., Kang, H.S., Chow, K.-S., Yeang, H.Y., Wagner, B., Breiteneder, H., and Han, K.-H. 1999. Isolation, characterization, and functional analysis of a novel cDNA clone encoding a small rubber particle protein (SRPP) from Hevea brasiliensis. Journal of Biological Chemistry 274(4): 17132-17138