A mitochondrial alkaline/neutral invertase isoform (A/N-InvC) functions in developmental energy-demanding processes in Arabidopsis

M.L. MARTÍN; .L. LECHNER; E.J. ZABALETA; G.L. SALERNO

PLANTA

SPRINGER

Lugar: Berlin; Año: 2013 vol. 237 p. 813 - 822

0032-0935

Recent findings demonstrate that alkaline/neutral invertases (A/N-Invs), enzymes that catalyze the breakdown of sucrose into glucose and fructose, are essential proteins in the plant life. The fact that different isoforms present multiple locations makes them candidates for coordination of metabolic processes. In the present study, we functionally characterized the encoding gene of a novel A/N-Inv (named A/N-InvC) from Arabidopsis, which localizes in mitochondria. A/N-InvC is expressed in roots, shoots and flowers. A detailed phenotypic analysis of knockout mutant plants (invc) reveals an impaired growth phenotype. Shoot growth was severely reduced, but root development was not affected as reported for A/N-InvA mutant (inva) plants. Remarkably, germination and flowering, two energy demanding processes, were the most affected stages. The effect of exogenous growth regulators led us to suggest that A/N-InvC may be modulating hormone balance in relation to the radicle emergence. We also show that oxygen consumption is reduced in both inva and invc in comparison with wild-type plants, indicating that the organelle isoenzymes may play a fundamental role in mitochondrion functionality. Taken together, our results emphasize the involvement of mitochondrial A/N-Invs in developmental processes and uncover different roles for the two isoforms located into the organelle.