Overexpression of Douglas-Fir () in Induces Embryonic Programs and Embryo-like Structures in the Mutant but Not in Wild Type Plants

Somatic embryogenesis (SE) is the most promising method for the quick propagation of desirable plant genotypes. However, application of SE to conifers remains challenging due to our limited knowledge about the genes involved in embryogenesis and the processes that lead to somatic embryo formation. Douglas-fir, an economically important lumber species, possesses a homolog of the angiosperm embryo-regulatory gene. In the present study, we analyzed the potential of Douglas-fir to induce embryonic programs in the vegetative cells of a heterologous host, . complemented the null mutant and led to a variety of phenotypes ranging from normal morphology to developmental arrest at various stages in the T1 generation. did not affect the morphology of wild type T1 plants. More profound results occurred in T2 generations. expression induced formation of recurrent somatic embryo-like structures in vegetative tissues of the rescued mutant but loss of apical dominance (bushy phenotype) in wild type plants. The activation of embryonic programs in the T2 plants was confirmed by the presence of the embryo-specific transcripts, and . In contrast, no embryo-like structures, and no or were observed in -expressing bushy wild type T2 plants.