Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Workshop: Forest Tree Genome Mapping
            

A GENOMIC APPROACH TO WOOD FORMATION IN LOBLOLLY PINE

¹ Department of Forestry, North Carolina State University, Raleigh, NC, 27695-7247

² Department of Environmental Horticulture, University of California at Davis, Davis, CA, 95616

³ Department of Forest Sciences, Texas A&M University, College Station, Texas, 77843-2135

⁴ Institute of Paper Science and Technology, 500 10th Street, NW, Atlanta, GA, 30318

⁵ Academic Health Center, University of Minnesota, M39 Masonic, UMHC 43, 420 Delaware St S.E., Minneapolis, MN 55455-0312

Wood formation is a highly specialized case of secondary cell wall biosynthesis, which has great significance for the pulp and paper industry and for the ecology of the world's forests. Our understanding of the process of wood formation will facilitate the domestication of forest trees as a crop, and the development of new wood products. We have organized a group of laboratories to use a genomic approach to investigate this process. We have identified large numbers of expressed genes through EST sequencing, and explored the patterns of expression of many of these genes through microarray analysis. We have combined this approach with mapping of quantitative traits related to wood properties and located candidate genes potentially affecting wood formation on the same genetic maps. About 60,000 ESTs have been sequenced from 4 libraries, sorted into contigs and singlets, and used to establish a unigene set of about 15,000 clones. Large numbers of pine genes have a high degree of homology to known plant genes, with substantial numbers implicated in cell wall formation. A fraction of the genes in the unigene set are new and show no clear relationship to Arabidopsis sequence or to sequences of other genomes in Genbank. Sequencing of ESTs has also uncovered large numbers of SNPs, which provide information for mapping, population genetics, and for inferring gene family structure. Microarrays have been developed using subsets of ESTs for analysis of expression during wood formation. Changes in gene expression have been observed and analyzed for wood forming tissues during normal growth, both juvenile and mature, under mechanical stress, and during the formation of early and late wood. Gene expression was examined in a mutation affecting the quality of lignin. These results provide a basis for future studies on the functional genomics of wood formation. The materials and methods that have been obtained and developed will permit detailed functional characterization of large numbers of genes implicated in wood formation. We expect to be able to define at least in part, the extent to which gymnosperms and angiosperms have similar modes of genome evolution, the extent to which gymnosperms and angiosperms share the same genes, and to identify a core of genes implicated in the biosynthesis of the secondary wall, through studies of wood formation. Our program has an outreach component, which includes a short course in Genomics for teaching at the high school level. Sequence information is available through the University of Minnesota (http://www.cbc.umn.edu/ResearchProjects/Pine/index.html) or through Genbank or Dendrome. Supported by a grant from the National Science Foundation Plant Genome Program (DBI 9975806).