Characterization of glyceraldehyde-3-P dehydrogenase non-phosphorylating (gapn) mutants of Arabidopsis thaliana

RIUS, S; CASATI, P; IGLESIAS, A; GÓMEZ-CASATI, D

Pinamar, Buenos Aires

Congreso; XLI Reunión Anual Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2005

SAIB

The role of non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) in plants was investigated by characterizing the effect of an insertion mutation at the gApn gene locus of Arabidopsis thaliana. gapn mutants showed absence in the expression of GAPN mRNA and lack of activity of this enzyme which cause an induction of cytosolic Ga3Pdh (GAPC) mRNA and an increase in its activity. Indeed, we observed higher levels of mRNA and activity of Glc6Pdh and also elevated concentrations of NADPH, but increased oxidative stress. The lack of GAPN protein decreased in the rate of CO2 assimilation per unit leaf area in agreement with the lower levels of chlorophyll observed in gapn lines compared with the wt plants. We found that GAPN gene is expressed in leaves and roots but induced in wt flowers. Our data based on microarray analysis of gapn plants also indicates a down-regulation of several genes suggesting that GAPN is important for efficient glycolysis and photosynthesis in plants and could be important for plant growth and development in Arabidopsis.