THE INCREASE OF PHOTOSYNTHETIC CARBON ASSIMILATION AS A MECHANISM OF ADAPTATION LOW TEMPERATURE IN LOTUS JAPONICUS

CALZADILA P.I.; VILAS J.M.; ESCARAY F.J.; UNREIN F.; CARRASCO P.; RUIZ O.A.

SCIENTIFIC REPORTS

NATURE

Lugar: NEW YORK; Año: 2019 vol. 9 p. 1 - 15

2045-2322

Low temperature isone of the most important factors affecting plant growth, directly altering thephotosynthetic process and leading to photo-inhibition. In order to address thephotosynthetic acclimation response of Lotusjaponicus to cold stress, two ecotypes with contrasting tolerance (MG-1 andMG-20) were studied. Their chloroplast responses were addressed after 7 daysunder low temperature through different strategies. Proteomic analysis showedchanges in photosynthetic and carbon metabolism proteins due to stress, butdifferentially between ecotypes. In the sensitive MG-1 ecotype acclimationseems to be related to energy dissipation in photosystems, while regulation ofthe carbon source/sink ratio seems to be preponderant in the tolerant MG-20ecotype. The accumulation of chloroplast starch granules in the tolerant MG-20ecotype indicates the maintenance of sugar metabolism under cold conditions inthis plant. Chloroplast ROS generation was measured by confocal microscopy andflux citommetry, showing higher levels under low temperature conditions only inthe MG-1 ecotype. This data was consistent with the ultrastructural alterationsobserved in their thylakoid membranes. Altogether, our data suggest thatdifferent acclimation strategies and contrasting chloroplast redox imbalancecould account for the differential cold stress response of both L. japonicus ecotypes