Analysis of primary carbon metabolism in celery leaves

MINEN RI; IGLESIAS AA; FIGUEROA CM

Buenos Aires

Conferencia; Fronteras en Biociencia 2; 2016

IBioBA

Sugaralcohols (like mannitol and glucitol) are major photosynthetic products in a significantnumber of agronomically important species. Sugar alcohols also play a key roleas compatible solutes under different abiotic stress conditions (including salinity,drought and cold). In celery (Apium graveolens)almost 80% of newly fixed CO2 is equally partitioned between sucroseand mannitol, while only a small part is allocated to starch. Carbonpartitioning in these plants is more complex than in other species and must beorchestrated accordingly. However, the molecular mechanisms regulating mannitolsynthesis, storage and transport are far from being well understood. In thiswork, we grew celery plants under long (16 h) and short (8 h) photoperiods,harvested leaves every 2 h for a complete light/dark cycle and measured the levelsof soluble sugars and starch. Preliminary results show that, irrespective ofthe photoperiod, starch content does not fluctuate on a diurnal basis. Thispattern differs from that observed for the model plant Arabidopsis thaliana, which accumulates large amounts of starch inleaves during the photoperiod to use it as carbon source during the followingnight. Our results suggest that carbon allocation is differentially regulatedin celery leaves and reveal that caution should be taken when extrapolatingresults to non-model species.