Taylor, Loverine
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Research Interests
Signal transduction pathways in pollen-pistil interactions and fertilization. Role of natural products in plant reproduction
Successful fertilization in plants depends on cell-cell communication between the male (pollen) and the female (pistil) components. When pollen falls on a receptive pistil it germinates and produces a rapidly growing tube that delivers the sperm cells to the embryo sac to initiate fertilization. My laboratory established that flavonols, C-15 bioactive aromatic molecules, function in a signal transduction pathway required for successful fertilization. Our research uses biochemical, molecular, genetic and cell biology techniques to determine the three major components of the flavonol-regulated germination pathway.

• The flavonol receptor. We have synthesized highly active affinity-tagged flavonols to identify and isolate the proteins that interact with, and transduce the flavonol signal.
  
• The metabolic fate of the flavonol signal. Kinetic analysis of a pollen-specific flavonol galactosyltransferase (F3GalTase) shows it regulates the ratio of active and inactive signal molecules. The role of F3GalTase during germination will be tested using a reverse genetic approach, e. g. antisense and RNAi transgenic plants.
  
• Downstream targets of the flavonol signal. We have identified several "flavonol-responsive" cDNA's that are transcriptionally activated in response to the flavonol signal. One cDNA encodes SHY, a leucine rich repeat protein that acts as a ligand for a receptor kinase involved in targeting the pollen tube to the ovule. Functional analysis of SHY uses the yeast two-hybrid system and transgenic plants expressing an antisense copy of the SHY gene in pollen.

A goal of this research is to control fertility by exploiting the pollen germination requirement for flavonols. The biotechnology aspects include the development of a reversible male sterile breeding system, increase plant yield, generate new hybrids and overcome interspecific breeding barriers.

Publications (1998 - Current)
Miller, K. D., J. Strommer and L. P. Taylor (2002). Conservation in divergent solanaceous species of the unique gene structure and enzyme activity of a gametophytically-expressed flavonol 3-O galactosyltransferase. Plant Mol Biol . 48: 233-242.

Taylor, L. P. and K. D. Miller 2002. The use of a photoactivatible kaempferol analogue to probe the role of flavonol 3 O-galactosyltransferase in pollen germination, In: J. Manthey and B. Buslig, eds., Flavonoids in Cell Function, Advances in Experimental Medicine and Biology 505: 41-50.

Tanaka, H, MM. Stohlmeyer, TJ Wandless, and LP Taylor (2000) Synthesis of flavonol derivatives as probes of biological processes. Tetrahedron Letters. 41(50) 9735-9740.

Guyon, V., J. D. Astwood, E. Garner, K. Dunker and L. P. Taylor (2000). Isolation and characterization of cDNAs expressed in the early stages of flavonol-induced pollen germination in petunia. Plant Phys.123: 1-12

Miller, K. D, V. Guyon, J. N.S. Evans, W A. Shuttleworth, and L. P. Taylor (1999) Purification, Cloning and Heterologous Expression of a Catalytically Efficient Flavonol 3-O-Galactosyltransferase Expressed in the Male Gametophyte of Petunia hybrida .J. Biol. Chem.274:34011-34019.

Napoli, C., D. Fahy, Wang, H-Y and L.P. Taylor, 1999. white anther: a petunia mutant that abolishes pollen flavonol accumulation, induces male sterility and is complemented by a chalcone synthase transgene. Plant Phys.120:615-622.

Taylor, L. P., D. Strenge, and K. Miller, 1998. The role of glycosylation in flavonol-induced pollen germination. In: J. Manthey and B. Buslig, eds., Flavonoids in the Living System, Plenum Press, New York., pp. 35-44.