Caracterização de determinantes genéticos envolvidos na qualidade industrial e nutricional do fruto de tomate / Characterization of genetic determinants involved in industrial and nutritional quality of tomato fruit

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

11/08/2011

RESUMO

This thesis addresses tomato fruit metabolism analysis by using three complementary approaches: i) the identification of candidate genes co-located with QTL previously described from metabolic profiles of S. lycopersicum (cv. M82) and S. pennellii introgressed lines, associated with industrial and nutritional quality traits; ii) the structural analyses of the genomic regions harboring the identified genes and ; iii) the functional analysis of the chaperone DnaJ and sec14 genes through reverse genetics mediated by iRNA silencing. The analysis of the molecular markers previously mapped onto the QTL-associated regions allowed the identification of 127 candidate genes whose products were mapped in the corresponding metabolic pathways. A subset of these genes showed allelic differences between the parental genotypes used for QTL identification. Based on these differences, together with the expression profile analysis and their putative function, two genes were selected for functional analysis using RNA interference approach. The phenotypic profile of the chaperone DnaJ deficient plants allowed to conclude that this protein, located in chloroplasts, participates in sugar metabolism, in particular, starch synthesis, controlling assimilates partitioning. The characterization of sec14-silenced transgenic lines leads to propose that fruit tocopherol (VTE) contents not only depend on the kinetic regulation of the biosynthesis-involved enzymes, but also on the SEC14 action, not yet characterized in plants. This protein might be involved in VTE transport between the different plastidial compartments thus, affecting oxidative balance, chloroplast structure and, consequently, VTE biosynthesis. All together these results support the hypothesis that wild germoplasm represents a remarkable source of variability to be explore aiming the identification of genetic determinants to develop new breeding approaches for tomato through metabolic engineering.

ASSUNTO(S)

fruit quality metabolism metabolismo qualidade de fruto solanum lycopersicum solanum lycopersicum tomate tomato

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