Recovered teak shoots retained their regrowth and regenerated into plantlets. A genetic transformation procedure for white pine has been developed after cocultivation of embryogenic tissues with Agrobacterium tumefaciens . This efficient transformation procedure led to an average of four independent transformed lines per gram of cocultivated embryogenic tissue and up to 50 transformed lines can be obtained in a routine experiment. We have utilized only Agrobacterium -mediated gene transfer system and have not used plant hormone regulation system of oncogenes for transformation. Alternatively, we have applied exogenous plant hormones to regenerate and proliferate transgenic tissues.
Oncogenes appear to have high flexibility for the regulation of endogenous plant hormonal levels.
However, oncogenes have not been used to induce proliferation and differentiation of transgenic cells because the regenerated transgenic plants exhibit a seriously abnormal phenotypes. To increase the number of transgenic plants and marker-free transgenic plants, we fused the ipt and R genes with different promoters and inserted into the MAT cassette to create new MAT vectors. We introduce improved version of MAT vectors for practical uses and their efficient application in woody plants. Millions of elms have been lost to the Dutch elm disease pathogen Ophiostoma novo-ulmi . Genetic modifications may overcome the lack of success achieved by traditional breeding using European elms allowing the introduction of desirable disease tolerance associated genes into elite genotypes.