David Hannapel
General Information
David Hannapel received his B.S. In Horticulture from the University of Illinois in 1978 and his M.S. in Horticulture from the University of Georgia in 1981. He received his Ph.D. in Horticulture from Purdue University in 1985. He was a postdoctoral research associate with John Ohlrogge working on fatty acid biosynthesis at the USDA NRRC, Peoria, IL from 1985 to 1987. David has been a member of the ISU Department of Horticulture since 1987. In addition, David is also a member of the Interdepartmental Plant Physiology Major, the Interdepartmental Genetics Major and the Molecular, Cellular, and Developmental Biology Program.
Dr. Hannapel's area of research interest is in developmental biology with a focus on the control of vegetative meristem determination and the role of transcription factors in regulating development. He has made use of potato tuberization as a model system to study signaling pathways that regulate growth and are mediated by photoperiod.
Dr. Hannapel is also involved in an NIH funded Botanicals Center (http://www.cdfin.iastate.edu/botanical/index.htm) working on in vitro propagation systems to enhance the production of bioactive compounds present in Echinacea species.
Current Research
Transcription factors are proteins that act as developmental switches by binding to the DNA of specific genes to regulate their expression. BEL1-like transcription factors interact with their protein partners from the knotted1-family to bind to target genes and regulate numerous developmental and metabolic processes. Recent studies have shown that specific BEL1 mRNAs of potato, designated StBEL5, are involved in a long-distance signaling pathway that mediates tuber induction. The transcriptional source of these mobile RNAs is leaf veins and petioles. Whereas photoperiod mediates the movement of StBEL5 RNA, activation of the StBEL5 gene in leaves is regulated by light, regardless of photoperiod. To define the regulatory elements in this promoter, deletion constructs were designed from the upstream region of StBEL5, fused with GUS and analyzed in transgenic plants. Upon illumination with either red or blue light, the StBEL5::GUS transgenic lines exhibited induced GUS activity whereas far-red light had no effect. Unlike flowering, the signaling pathway for tuber formation arises in a light-grown organ, the leaf, and is transmitted to an underground organ, the stolon. In stolons, the StBEL5 promoter was active in the dark but its activity was repressed when these stolons were grown in light. This dark activity in stolons and the presence of a tandem TTGAC motif, specific for interaction with the BEL/Knox duplex, on the BEL5 promoter suggest the possibility of auto-regulation. These studies implicate the transcripts of BEL5 in a long-distance signaling pathway that are delivered to the target organ via the phloem stream.
A long-distance signal for tuber induction in potato. This signaling pathway is based on the initial transcriptional activation by light (yellow arrows) of the StBEL5 gene in the veins of leaves and petioles (blue). A short-day photoperiod (inductive for tuber formation) facilitates movement of the StBEL5 RNA through the petiole junction into the stem (red arrows). The RNA moves to stolon tips, is translated, and binds to a Knox protein partner (brown line) to regulate transcription of select target genes by binding to the tandem TTGAC motif in the promoter.
Patents
- Patent filed: ISURF # 03056, “Mobile RNAs Act as a Signal to Control Plant Growth”
- Patent filed: ISURF # 02885, “Overexpression of Two Potato Transcription Factors Enhances Tuber Formation”
Selected Publications
Yu, Y.Y., Lashbrook, C.C., and Hannapel, D.J. 2007. Tissue integrity and RNA quality of laser microdissected phloem of potato. Planta (online version March, 2007).
Hannapel, D. J. 2007. Signaling the induction of tuber formation, in Potato Biology and Biotechnology: Advances and perspectives, Editors: C. Gebhardt, D. MacKerron , R. Viola, and D. Vreugdenhil, (in press)
Banerjee, A. K, Yu, Y., Chatterjee, M., Suh, S.G., Miller, W.A. and Hannapel, D.J. 2006. Dynamics of a mobile RNA of potato involved in a long-distance signaling pathway. The Plant Cell 18: 3443-3457.
Banerjee, A. K, and Hannapel, D. J. 2006. Efficient production of transgenic potato (S. tuberosum L. ssp. andigena) plants via Agrobacterium tumefaciens-mediated transformation. Plant Science 170: 732-738
Romero, F.R., Delate,K., and D. J. Hannapel. 2005. The effect of seed source, light during germination, and cold-moist stratification on seed germination in three species of Echinacea. HortScience 40: 1751-1754.
Chen, H, Banerjee, A. K, and Hannapel, D. J. 2004. The tandem complex of BEL and KNOX partners is required for transcriptional repression of ga20ox1. Plant J 38: 276-284.
Hannapel, D. J., Chen, H., Rosin, F.M., Banerjee, A. K., and Davies, P.J. 2004. Molecular controls of tuberization. Amer J Potato Res 81:5-16
Chen, H., Rosin, F.M., Prat, S., and Hannapel, D. J. 2003. Interacting transcription factors from the TALE superclass regulate tuber formation. Plant Physiol 132: 1391-1404.
Rosin, F.M., Aharoni, A., Salentijn, E.M.J., Schaart, J.G., Boone, M.J., and Hannapel, D.J. 2003. Expression patterns of a putative homolog of AGAMOUS, STAG1, from strawberry. Plant Science 165: 959-968
Rosin, F.M.,Hart, J.K., Harry T. Horner, H.T., Davies, P.J., and Hannapel, D.J. 2003. Overexpression of a Knotted-like homeobox gene of potato alters vegetative development by decreasing gibberellin accumulation. Plant Physiol. 132: 106-117.
Rosin, F.M., Hart, J.K. , Van Onckelen, H. and Hannapel, D.J. 2003. Suppression of a vegetative MADS box gene of potato activates axillary meristem development. Plant Physiol. 131: 1613–1622.
Hart, J. K. and Hannapel, D. J. 2002. In situ hybridization of the MADS-box gene POTM1 during potato floral development. J. Expt. Botany 53: 465-471.
Kolomiets, M.V., Hannapel, D.J., Chen, H., Tymeson, M., and Gladon, R.J. 2001. Lipoxygenase is involved in the control of potato tuber development. Plant Cell 13: 613-626.
Kolomiets, M.V., Chen, H.,. Gladon, R. J , Braun, E. J., and Hannapel, D. J. 2000. A leaf lipoxygenase of potato induced specifically by pathogen infection. Plant Physiol. 124: 1121-1130.
Immink, R.G.H., Hannapel, D.J., Ferrario, S., Busscher, M., Franken, J., Lookeren Campagne, M., and Angenent, G. C. 1999. A petunia MADS box gene required for transition from the vegetative to the reproductive phase. Development 126: 5117-5126.
Kang, S.G. and Hannapel, D.J. 1996. A novel MADS-box gene of potato (Solanum tuberosum L.) expressed during the early stages of tuberization. Plant Mol Biol 31: 379-386.
