Cloning and characterization of six embryogenesis-associated cDNAs from somatic embryos of Picea glauca and their comparative expression during zygotic embryogenesis

Six somatic embryogenesis-associated cDNAs (PgEMB2, 6, 7, 8, 24 and 34) fro m white spruce (Picea glauca (Moench) Voss) somatic embryos have been chara cterized. Transcript accumulation during somatic embryo development and sub sequent germination related to these genes, indicated that they were develo pmentally regulated. The transcripts related to clones PgEMB2, 6, 24 and 34 were also detected during zygotic embryo development, but transcripts of c lones PgEMB7 and 8 were not. PgEMB24 had a similar gene expression pattern to spruce Em-like late embryo abundant (lea) gene, but other clones had no similarities in gene expression to either spruce lea-like or storage protei n genes. Abscisic acid, a stimulator for spruce somatic embryo maturation, did not obviously affect gene expression corresponding to these cDNAs. The predicted proteins are distinguishable from known LEA proteins based on ana lyses of hydropathy plots, amino acid compositions and deduced protein stru ctures. The similarities of the spruce cDNAs, and protein sequences predict ed from these cDNAs, to other sequence data are described.