Vargas, Walter A. , Pontis, Horacio G. , Salerno, Graciela L. .
Differential functions of alkaline and neutral invertases connected with environmental stress responses in wheat leaves.
Among sucrose (Suc) metabolism enzymes, alkaline/neutral invertases (A/N-Inv) are the less studied. These enzymes exist as two different isoforms, alkaline- or neutral-isozymes (A-Inv or N-Inv, respectively) differentiated by the optimum pH for catalysis. They were biochemically characterized in some plant species and only two coding sequences, both of them for N-Inv (from Daucus carota and Lolium temulentum) were identified and functionally characterized; however, neither any sequence from plants was described as coding for an A-Inv nor isoform-related roles have been proposed for A/N-Inv. In the present work, we report the first sequence coding for an A-Inv from Triticum aestivum (Ta-A-Inv) after its functional characterization. We performed biochemical and molecular studies at enzymatic and transcriptional levels of Ta-A-Inv in different growth conditions. Our results demonstrate that Ta-A-Inv is responsible for the expression of a stress–related A-Inv. The differential expression regulation of both isoforms in wheat seedlings under osmotic stress and low temperatures, supports a distinct physiological function of A-Inv and N-Inv. A comprehensive analysis of metabolites and other enzymes involved in Suc metabolism led as to conclude that A-Inv may be responsible for a more efficient Suc hydrolysis to supply the carbon and energy demands imposed for the stressful situations.
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1 - Fundación para Investigaciones Biológicas Aplicadas (FIBA), Centro de Investigaciones Biológicas, Vieytes 3103, Mar del Plata, Buenos Aires, 7600, Argentina
2 - Fundación para Investigaciones Biológicas Aplicadas (FIBA), Centro de Investigaciones Biológicas
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM