Nieves Vidal

Information on public awareness and acceptance issues regarding the use of Genetically Modified (GM) trees in forestry is lacking, although such information is available for GM organisms in agriculture. This is mainly due to the fact that in Europe there is no authorization for commercial planting of GM forest trees. To address this issue and within the frame of a European COST Action on the Biosafety of Transgenic Forest Trees (FP0905), a KAP (Knowledge Attitude Practice ) cross-country pilot survey was conducted among university students of different disciplines as sampling subjects. In total, 1920 completed questionnaires from 16 European and non-European countries were evaluated. The results provided novel cross-country insights into the level of public knowledge, particularly of young people and their perceptions on safety issues related to the use of GM forest trees , as well as on their attitude towards the acceptance of GM forest trees cultivation. The majority of the respondents, which was more than 60 % in all countries, approved the use of GM forest trees for commercial plantations , excluding natural forests. The majority of respondents also appeared willing to buy products from such plantations, such as wood products, pulp and paper. Over 80 % of the respondents from all countries were in favour of using labelling to identify products of GM origin, while more than 80 % of those would prefer that this labelling be legally mandatory. The top three benefits that were rated as very important in all countries involved the potential lower demand of the GM forest plantations for pesticides, the potential of GM forest trees for restoration of contaminated soils and the potential higher GM forest tree productivity. The top three GM forest tree risks that were perceived as serious hazards in all countries included the potential loss of biodiversity due to gene flow between transgenic and wild trees, the adverse effects of biotrophic processes on host ecosystems and the cultural adaptation to changing biodiversity conditions due to transgene escape. Overall, lack of knowledge regarding the potential benefits and potential risks of the cultivation of GM forest trees was observed in almost all surveyed countries.

The genus Quercus, which belongs to the family Fagaceae, is native to the northern hemisphere and includes deciduous and evergreen species. The trees of the different species are very important from both economic and ecological perspectives. Application of new technological approaches (which span the fields of plant developmental biology, genetic transformation, conservation of elite germplasm and discovery of genes associated with complex multigenic traits) to these long-rotation hardwoods may be of interest for accelerating tree improvement programs. This review provides a summary of the advances made in the application of biotechnological tools to specific oak species. Significant progress has been made in the area of clonal propagation via organogenesis and somatic embryogenesis (SE). Standardized procedures have been developed for micropropagating the most important European (Q. robur, Q. petarea, Q. suber) and American (Q. alba, Q. bicolor, Q. rubra) oaks by axillary shoot growth. Although regenerated plantlets are grown in experimental trials, large-scale propagation of oak species has not been carried out. The induction of SE in oaks from juvenile explants is generally not problematic, although the use of explants other than zygotic embryos is much less efficient. During the last decade, enormous advances have been made in inducing SE from selected adult trees, mainly specimens of pedunculate oak (Q. robur) and cork oak (Q. suber). Advances in the understanding of the maturation and germination steps are required for better use of embryogenic process in clonal forestry. Quercus species are late-maturing and late-flowering, exhibit irregular seed set, and produce seeds that are recalcitrant to storage by conventional procedures. Vitrification-based cryopreservation techniques were used successfully in somatic embryos of pedunculate oak and cork oak, and an applied genbank of cork oak selected genotypes is now under development. The feasibility of genetic transformation of pedunculate oak and cork oak somatic embryos by means of co-culture techniques with several strains of Agrobacterium tumefaciens has also been demonstrated. To date, most research on the genomics of Quercus species has concerned population genetics. Approaches using functional genomics to examine the molecular and cellular mechanisms that control organogenesis and or somatic embryogenesis are still scarce, and efforts on the isolation and characterization of genes related to other specific traits should be intensified in the near future, as this would help improve the practical application of clonal forestry in recalcitrant species such as oaks.

Plants of European chestnut (Castanea sativa) have been consistently recovered from cryopreserved in vitro-grown shoot apices by using the vitrification procedure. Factors found to influence the success of cryopreservation include the source of the shoot tips (terminal buds or axillary buds), their size, the duration of exposure to the cryoprotectant solution, and the composition of the post-cryostorage recovery medium. The most efficient protocol for shoot regrowth employed 0.5–1.0 mm shoot tips isolated from 1 cm-long terminal buds that had been excised from 3–5-wk shoot cultures and cold hardened at 4°C for 2 wk. The isolated shoot tips were precultured for 2d at 4°C on solidified Gresshoff and Doy medium (GD) supplemented with 0.2M sucrose, and were then treated for 20 min at room temperature with a loading solution (2M glycerol+0.4M sucrose) and for 120 min at 0°C with a modified PVS2 solution before rapid immersion in liquid nitrogen (LN). After 1 d in LN, rapid rewarming and unloading in 1.2M sucrose solution for 20 min, the shoot tips were plated on recovery medium consisting of GD supplemented with 2.2 μM benzyladenine, 2.9 μM 3-indoleacetic acid, and 0.9 μM zeatin. This protocol achieved 38–54% shoot recovery rates among five chestnut clones (three of juvenile origin and two of mature origin), and in all cases plant regeneration was also obtained.