Clonal propagation by somatic embryogenesis (SE) has the potential for
the delivery of superior material to the commercial forest in a much
shorter time and used in combination with the sexual process for seed
production will help maintain the correct genetic balance from seed
orchards. Presently constraints to successful introduction of
commercial embryogenesis are perceived to be (a) improvement of embryo
quality, and (b) efficiency and number of responding genotypes. The
ultimate understanding of embryogenesis depends on our knowledge of
the genes that are expressed during embryo development. However, few
embryo-specific genes have been identified in conifers. To understand
the molecular basis of embryogeny, we have isolated and characterized
the Douglas fir cDNAs and genomic clones of genes expressed during
development and the probes used to examine mRNA profiles of maturing
embryos of various genotypes and to elucidate effects of cultural
conditions on quality of SE. The analyses of corresponding genomic
sequences using GFP/GUS chimeric constructs and deletion mutants in
transgenic plants were also carried out. The details of our findings
on 2S storage protein genes, MT-like gene and a molecular chaperone
BiP will be presented at the meeting. Our studies have provided
important information on molecular biology of conifer embryo
maturation and form the basis of continuing focus on early stages of
embryogeny. Research was supported by an NSERC Research Grant to SM.
Key words: BiP, conifers, embryos, gene expression, MT, seed germination