Lee H. Pratt

PI: Jeffrey Dean
Co-PIs: Marie-Michèle Cordonnier-Pratt, Sarah Covert, Scott Merkle, Lee Pratt
Key collaborators: Alan Gingle, W. Walter Lorenz, C. Joseph Nairn, III, Rodney Will

Wood accounts for 25% of the value of all industrial materials produced in the U.S. On an annual basis, the value of wood-derived products equals or exceeds that of every other agricultural crop but maize. However, losses in production forest acreage, coupled with increasing demands for paper and cheap fiber supplies from overseas, have put intense pressure on U.S. companies to increase wood yields per acre, particularly in southeastern forests. Unfortunately, our limited understanding of tree biology constitutes a significant barrier to attaining the productivity gains necessary to keep pace with the rising consumer demand for wood products. A previous project to catalog the genes expressed in wood-forming tissues of loblolly pine (Pinus taeda), the predominant commercial tree species in the southeastern U.S., placed more than 65,000 ESTs in the public domain. While that collection provides an excellent starting point for studies of wood formation, it is incomplete with respect to many genes that will be important for increasing forest productivity in the future.

Our project will expand the current loblolly pine EST set by ˜140,000 ESTs (˜70,000 cDNAs) derived primarily from roots experiencing a variety of biotic and abiotic stresses. Particular effort will be made to identify ESTs for genes that respond to those environmental and biological stresses trees will likely experience under intensive management regimes. Data from this project will be integrated with that from a concurrent study of pine embryogenesis, as well as the preceding wood formation study, so that a comprehensive unigene set can be assembled for the user community. DNA microarrays will be used to identify genes whose expression varies in response to various environmental and developmental cues, such as mineral or nutrient deficiencies and interactions with mycorrhizal fungi.

Identification of environmentally responsive genes will provide for better understanding of the molecular mechanisms trees use to respond to environmental and biological stresses. These genes will enable the development of new techniques, such as targeted microarrays, with which to monitor in near real-time the effects of modified silvicultural practices on tree growth and development. Such new techniques will provide the means for addressing current biological constraints that limit forest productivity in the southeastern U.S.