Nonlinear Projective Filtering of ECG Signals
Marian Kotas · InTech eBooks · 2009
IntroductionGenetic transformation provides the means for adding single horticultural traits in existing cultivars without modify their commercial characteristics.This capability is particularly valuable for perennial plants and fruit tree species, in which conventional breeding is hampered by their long generation time and juvenile periods, complex reproductive biology, high levels of heterozygosity, limited genetic sources and linkage drag of undesirable traits from wild relatives.In addition, gene transfer technologies for fruit tree species take the inherent advantage of vegetative propagation used for their reproduction, which allowed for the application of a high scale production of the desired transgenic line starting from one successful transformed line.Despite this opportunity, final setting of transformation protocols in this type of species, endures major limiting factors preventing the development of new varieties: a) explants recalcitrance to regenerate adventitious transformed shoots and b) a limited regeneration capability, usually extended to just few genotypes (i.e.cultivar dependence).This chapter illustrates the road between the establishment of transformation methodologies on particular species of Vitis spp.and Prunus spp.and their use as technical baselines for achievement of transformation procedures in new, eventually more recalcitrant, cultivars or genus members. Genetic transformation of fruits in the current research eraGenetic improvement of fruit trees is essential for increasing fruit production.For most of these species, the desired new varieties contemplate the presence of agronomic and horticultural traits related to propagation, yield, appearance, quality, disease and pest control, abiotic stress and shelf-life.Incorporation of these traits into the genetic backgrounds of species by conventional breeding needs overcome some major disadvantages, including long juvenile periods and reduced possibility of introgression of the suitable traits (when available) into commercially relevant cultivars.Although currently the use of new technologies based on high throughput platforms for sequencing and genotyping has deeply contributed to accelerate the association of molecular markers and major genes to these relevant traits, there exists a bottle neck in this strategy when www.intechopen.comGenetic Transformation 82 phenotyping must be carried out.In addition, breeding by controlled crosses is hampered due to factors specifically related to complex characteristics belonging to these species, such as delayed flowering, unsuccessful fruit setting due to abortive embryos, massive fruit drop, and self-incompatibility barriers found in many of them.Genetic transformation represents inherent advantages for fruit tree improvement, although in fruit trees this area of research is not a routine procedure.The transversal negative perception about the "transgenic technology" is added to an additional degree of difficulty for setting up adequate technical systems in fruit tree species.Eventually, if a proper regenerative system has been established, any DNA construct designed for either a major gene over-expression or gene silencing (i.e.interfering RNA´s in vivo generation) can be introduced into a desired genome.Consequently, the feasibility of genetic modification relies on adequate technical systems which allowed for results in a reasonable time frame.Regardless the final objectives of transformed events (a product or fundamental research), highly regenerative systems for explants production and whole plants regeneration are key steps of fruit tree genetic transformation.In addition, the relevance of these procedures is even higher when an era of candidate genes evaluation has begun as a result of the current knowledge about genomes. Use of grapevine systems as a model in fruit species Grapevine somatic embryogenesis and genetic transformation of somatic embryosSince its first report in 1976 (Mullins and Srinivasan, 1976), somatic embryogenesis (SE) in Vitis vinifera L. has been described in different cultivars and their hybrids (Martinelli and Gribaudo, 2001, 2009), becoming the most efficient procedure for the generation of in vitro cultures prone to genetic transformation (Stamp and