Profiling trascrizionale e proteomico comparativo della cv. di frumento tenero Bobwhite e della sua corrispondente linea transgenica che sovraesprime un gene codificante una lmw-gs
Author(s)
Scossa, Federico
Date Issued
March 14, 2006
Type
Doctoral Thesis
Abstract
Since wheat is indisputably one of the major food crops in the world and the single most important source of plant protein in the human diet, it has always been a target of choice for classical and biotechnological-oriented breeding programs.
The quality of the wheat end-use products is largely determined by the gluten proteins, a complex mixture of polypeptides accounting for up to 80% of the total seed proteins. Gluten proteins are the determinants of the visco-elastic properties of the wheat doughs, and their quantity in the seeds is directly correlated with the quality of end-use products.
Recent efforts to increase the quantity of gluten proteins in the seeds focused on the introduction of additional gene copies by means of genetic engineering technology. We have thus produced and extensively characterized an independent transgenic bread wheat line overexpressing a LMW-GS (Low Molecular Weight-Glutenin Subunit), whose relative quantity in the seed is expected to positively affect the technological properties of the flour.
In order to define the consequences of transgene(s) insertion/expression and the effects of genetic transformation on the global endosperm gene expression, we carried out a comparative proteomic and transcriptional profiling between the seeds of the transgenic line with its non-transformed counterpart.
Microarray analysis showed that, during the seed development, 542 unigenes were significantly differentially expressed. Those genes for which a reliable annotation was available have been classified, according to their putative functional category, to provide an overview of the genome responses to genetic transformation and trasgene(s) expression. By expression pattern matching, we identified a number of genes strongly correlated to the expression of the transgenes during the process of seed maturation. The implications of the lmw-gs over-expression on the partitioning and accumulation of storage reserves in developing wheat grains are also discussed.
Evidence for differential expression of several seed storage-related genes was confirmed at the protein level, both in developing and mature seeds, with quantitative proteomic analyses of the corresponding encoded subunits.
Our data define in part the downstream responses in developing seeds to genetic transformation and over-expression of a lmw-gs transgene in bread wheat.
Additional information
Dottorato di ricerca in Biotecnologie vegetali
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