Data di Pubblicazione:
2001
Citazione:
Modification of fruit tree architecture by biotechnology approaches / M.C. Piagnani. ((Intervento presentato al convegno Italy-Korea joint Symposium in Agrifood Biotechnology tenutosi a Suwon, South Corea nel 2001.
Abstract:
Italy produces high quantity of fruit whose major part is exported in other countries. Other countries invest a large amount of their economical resources into the area of genetic improvement and plant development study. In many cases plant growers and farmers of our country must pay royalties to other countries for plant breeding technologies, for using improved cultivars. Nonetheless, these cultivars are not always adapt to our needs and environmental conditions. Cherries and apricots are of great economic interest both for areas of high intensity investments and for marginal ones, these have problems linked with strong apical dominance (cherry, and in some cases apricot), impeding the cultivation of modern fruit production technologies, problems linked with flowering period, with fruit ripening, with problems of self-incompatibility and cold tolerance.
The objective of this research, which involves seven Research Units from several Italian public labs, is to improve the knowledge about growth and development of fruit crops, through the studies of two important factors such as light and plant growth regulators and their interactions. In this context biotechnologies are used for two main reasons: the first one is to evaluate their possible use as a method of genetic improvement and the second is to understand how light and hormones act and integrate in order to determine the development and architecture of the plant.
Plant photoreceptors are involved in light dependent responses. Overexpression of phytocrome a and b (belonging to the multigene family encoding phytocrome) has been demonstrated to induce phenotipic consequences such as short hypocotyl in transgenic Arabidopsis seedlings (Wagner, 1991) and reduction of apical dominance in transgenic fruit trees (Muleo e Iacona,1998). The genes that we are going to use for plant transformation are phytochrome A (phyA) of rice, phytochrome B (phyB) of Arabidopsis thaliana and the rol genes of A. rhizogenes. Both, phyA and phyB, control the biochemical signal regulating the expression of the strategy of plants development (avoidance shade syndrome), the proteins of the rol genes interact with the signal chain of the hormones which have a preponderant role in the plant development. We expect that the over expression of phytochrome genes will induce phenotypic modifications affecting apical dominance, reduced canopy development, functional and dimensional development of root system, flowering time, reduction of juvenile period. Nevertheless the use of genetic transformation requires a suitable regeneration systems. Plant regeneration from fruit tree is in most cases difficult to achieve. In spite of several reports on Prunus spp only a few literature referring to regeneration from mature tissues of Prunus avium cultivars is available (Yang et al. 1991, Hammat and Grant 1998, Negri et al. 1998). In our lab we are testing regeneration ability from mature explants of several Prunus avium cultivars and a regeneration protocol for cultivar Hedelfinger has been set up. Nevertheless Hedelfinger is demonstrated to be a recalcitrant genotype as indicated by the very poor regeneration frequencies obtained and by the fact shoot regeneration has quite a discontinuous trend. At the present time other commercially relevant cultivars, such as Lapins and Burlat C1, are now under testing to determine the conditions to induce regeneration.
Regenerated plantlets from cultured tissues can undergo somatic stable variation and meiotically heritable variation caused by the in vitro process. So, random and frequent genetic variability occurring in cell cultures is preserved among the population of regenerants. Despite this, very little is understood about how somaclonal variation can occur and be regulate
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Elenco autori:
M.C. Piagnani
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