Mechanisms of regulation of oleic and linoleic acid content in olive oil due to the effect of high temperature. Integrating molecular and ecophysiological scales.

GARCÍA-INZA, GEORGINA P.; HERNANDEZ, MARIA LUISA; MARTÍNEZ-RIVAS, JOSÉ MANUEL; MISERERE, ANDREA; ROUSSEAUX, M. C.

Rosario

Congreso; XXXIII Reunión Argentina de fisiología vegetal; 2021

Ambient temperature during olive fruit growth modulates the proportion of the main fatty acids in the oil. Experiments in which temperature was manipulated showed that the oleic acid concentration decreased 0.7%°C−1 with the increase in temperature. Fatty acid unsaturation is mediated by fatty acid desaturases, such as the FAD2 gene family that is involved in the conversion of oleic to linoleic acid, the main fatty acids that determine olive oil quality. The aim of this work was to elucidate the mechanisms behind olive oil fatty acid composition in response to high temperature, integrating responses at the gene expression and ecophysiological scale. Trees of cultivars Arbequina and Coratina were placed in field open top chambers during the period of active oil accumulation. Two treatments were applied: control and heated (+3 ° C, compared to control) for 36 days. Gene expression and fatty acid analysis revealed that oleic acid in mesocarp oil significantly decreased 2.6 and 6.6 percentage points in ´Arbequina´ and ´Coratina´ after 36 days of exposure to high temperature. This response was consistent with the upregulation of the relative transcript abundance of FAD2-5 in ´Arbequina´ and ´Coratina´ and FAD2-2 in ´Coratina´. Linoleic acid content was linearly related to FAD2-5 transcript abundance (R2=0.6 and R2=0.4, for ´Arbequina´ and ´Coratina´, respectively). This work points out how temperature modulates the proportion of the main fatty acids through the transcriptional regulation of the FAD2 genes, affecting oil quality.