Initiation of leaf somatic embryogenesis involves high pectin esterification, auxin accumulation and DNA demethylation in Quercus alba.

Somatic embryogenesis is considered a convenient tool for investigating the regulating mechanisms of embryo formation; it is also a feasible system for in vitro regeneration procedures, with many advantages in woody species. Nevertheless, trees have shown recalcitrance to somatic embryogenesis, and its efficiency remains very low in many cases. Consequently, despite the clear potential of somatic embryogenesis in tree breeding programs, its application is limited since factors responsible for embryogenesis initiation have not yet been completely elucidated.

Induction of somatic embryogenesis in explants of shoot cultures established from adult Eucalyptus globulus and E. saligna × E. maidenii trees.

A reproducible procedure for induction of somatic embryogenesis (SE) from adult trees of Eucalyptus globulus Labill. and the hybrid E. saligna Smith × E.

Chestnut, European (Castanea sativa).

Development of a system for direct transfer of antifungal candidate genes into European chestnut (Castanea sativa) would provide an alternative approach to conventional breeding for production of chestnut trees that are tolerant to ink disease caused by Phytophthora spp. Overexpression of genes encoding PR proteins (such as thaumatin-like proteins), which display antifungal activity, may represent an important advance in control of the disease. We have used a chestnut thaumatin-like protein gene (CsTL1) isolated from European chestnut cotyledons and have achieved overexpression of the gene in chestnut somatic embryogenic lines used as target material.

Genetic transformation of European chestnut somatic embryos with a native thaumatin-like protein (CsTL1) gene isolated from Castanea sativa seeds.

The availability of a system for direct transfer of antifungal candidate genes into European chestnut (Castanea sativa Mill.) would offer an alternative approach to conventional breeding for production of chestnut trees tolerant to ink disease caused by Phytophthora spp. For the first time, a chestnut thaumatin-like protein gene (CsTL1), isolated from chestnut cotyledons, has been overexpressed in three chestnut somatic embryogenic lines.