Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Forest Trees
            

DETECTION OF THE SEQUENCE MUTATION RESPONSIBLE FOR A NULL ALLELE OF CINNAMYL ALCOHOL DEHYDROGENASE IN LOBLOLLY PINE.

¹ Environmental Horticulture, University of California, Davis, CA 95616 USA

² Institute of Forest Genetics, USDA Forest Service, Davis CA 95616 USA

Loblolly pine clone 7-56 is heterozygous for a null allele of cinnamyl alcohol dehydrogenase (CAD). Seedlings that are homozygous for the null allele contain between 0-1 % of wild type CAD activity and display drastic changes in lignin composition. The sequence variant responsible for the null allele has previously remained unknown. During SNP discovery in the cad gene for association studies, we found unique to the mutant a two-base pair adenosine insertion which causes a frame-shift and generates a premature stop codon. A direct correlation of the sequence mutation with the loss of CAD activity was found among haploid megagametophytes of 7-56. For routine detection of the mutation, a diagnostic assay was developed utilizing single primer extension and fluorescence polarization. Results obtained from trial testing of the assay will be presented.