Analisi citogenetica della potenziale instabilità genetica in linee di frumento transgenico, comparate alla controparte wild type, in seguito ad insulti genotossici con agenti mutageni chimici e fisici
Author(s)
Bellacima, Raffaela
Date Issued
March 22, 2011
Type
Doctoral Thesis
Abstract
The advent of GM technology in the early 1970s has determined to date, that over 30 million hectares of transgenic crops have been grown with the consequence that present day cultivated crops have become significantly different from their wild counterparts generated through classical plant breeding.
Numerous potential concerns have been raised since the development of GM technology. Such concerns have focused on the potential for allergic reactions to food products, the possible introduction or increase in production of toxic compounds as a result of this technology, and the use of antibiotic resistance as markers in the transformation process. Very little is known about long term effects of ingestion of transgenic including their genomic stability.
In the present study, we aimed to assess potential genomic instability of transgenic wheat lines exposed to physical and chemical genotoxic agents with different mechanisms of actions:
-Camptothecin: catalytic inhibithor of DNA topoisomerase I which selectively induces DNA single strand breaks (SSB’s);
-Etoposide: catalytic inhibithor of DNA topoisomerase II which selectively induces DNA doble strand breaks (DSB’s);
- X-rays: induce SSB’s, DSB’s, abasic sites, base damage directly and indirectly by radiolysis of water;
-Ultraviolet C radiation (UV-C): induces essentially pyrimidine dimers and 6-4-photoproducts
The listed DNA lesions trigger many different DNA repair pathways including excision repair, DNA single strand break repair; homologous and non-homologous DNA end-joining etc..
Genetic instability has been evaluated by induction of chromosomal aberrations and micronuclei in proliferating cells of root tips of transgenic crops and their wild type counterparts following genetic damage.
The following wheat lines have been used:
The exaploid (42 chromosomes) Triticum aestivum transgenic by biolistic method for the line “LMW-GS” (low molecular weight glutenin subunits) which induce modification of the visco-elastic properties of the wheat doughs and the line “PGIP” (polygalactorunase inhibiting protein) which increased resistance to digestion of fungal PG.
The tetraploid (28 chromosomes) Triticum durum transgenic by Agrobacterium tumefaciens with a single gene copy of RNA interference to silence the gene starch branching enzyme IIa (SBEIIa) for increase the amylose content, beneficial for human health effects.
Additional information
Dottorato di ricerca in Biotecnologie vegetali
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