Analisi proteomica in linee di frumento duro high-amylose transgeniche e corrispondenti wild-type
Author(s)
Paoletti, Federica
Date Issued
April 20, 2012
Type
Doctoral Thesis
Abstract
Wheat is widely cultivated in the world and represents one of the cereals most important
for the human diet. The parameters that mainly influence semolina and flour quality are
the proteins and the starch. Starch is of remarkable interest because it can be used for
various applications in food and non food industry. It is composed by amylose and
amylopectine, whose relative amounts affect its chemical-physical properties and final
uses, along with the structure of starch granules and lipids. In the last years various
studies have been performed to clarify the mechanisms that regulate starch biosynthesis,
in order to produce starches with specific properties, such as a higher amylose content,
that has beneficial effects on human health.
In our laboratory, high amylose transgenic lines of durum wheat have been produced
through the silencing of the Starch Branching Enzyme IIa (SBEIIa) genes. In this work,
a 2D electrophoretic comparison between the kernel proteome of a transgenic line of the
durum wheat cultivar Svevo with silenced SBEIIa genes and the corresponding
untransformed line have been performed. In particular, two developing stages have been
considered: the dough (15 dpa) and ripening (physiological maturity) stages.
As for the mature stage, the differentially expressed proteins have been identified by the
software SameSpots Progenesis (Nonlinear Dynamics, UK) and characterized by
MS/MS. In order to compare the effects produced by two different methods of genetic
transformation on the proteome of kernels of durum wheat. From the analysis of
proteins extracted from starch granules and metabolic fraction, 32 spots were identified
differentially expressed between by transgenic line MJ16-112 (obtained by biolistic
method) and cultivars Svevo and 37 spots differentially expressed on the transgenic line
A431_4p1a (obtained by mediated transformation dall'Agrobatterio) and on the cultivar
Ofanto. The proteins were observed as differentially expressed: proteins involved in
carbohydrate metabolism, defense mechanisms and biosynthetic processes in the
caryopsis of wheat. Changes in carbohydrate metabolism may be considered
"expected", since it has been manipulated the biosynthetic pathway of starch in the GM
lines, while there were no major differences regarding the presence of hazardous
substances or allergens in the transgenic kernels . In conclusion, the two processing
methods have similar effects in both protein fractions, and that these effects do not
seem, therefore, influenced by the different methods of transformation.
Additional information
Dottorato di ricerca in Biotecnologie vegetali 24. ciclo
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