Salicylic acid modulates oxidative stress during the ontogenesis of rice (Oryza sativa L.) grain measured by UHPLC-QqQ-MS/MS oxylipin-based lipidomics

The present study aims to discover the effect of exogenously applied of salicylic acid (SA) in the concentration 0, 1 and 15 mM, on the oxidative stress monitored through the concentration of PhytoPs and PhytoFs in immature and mature grains of three genotypes of rice ('R52', 'R45' and 'Yerua') and their influence on grains per panicle and chalkiness. Concentration of oxylipins showed differences in both harvest times (immature and mature) for each genotype. The cv 'Yerua' presented equal concentrations of PhytoPs in immature and mature grains, while the mature grains of the advanced lines 'R52' and 'R45' showed concentrations 24.0 and 79.0% lower than those of the immature grains, respectively. The PhytoFs were equivalent in the two harvest seasons, in "Yerua" and "R52", while in "R45", the concentration of these oxylipins was 46.0% lower in the mature grains. Regarding the effect of SA treatments, it was observed that a single application reduced the concentration of a single oxylipin of the ten quantified; while in mature grains, with two applications of SA, a significant decrease in the concentration of 6 of the ten biomarkers monitored was observed with the increase in the concentration of SA. The SA produced an increase in grains per panicle and a decrease in chalkiness, especially in "R52". The close relationship between the content of the oxylipins evaluated and the concentration of SA applied confirms the relationship of their participation in the redox balance and the ability to mitigate stress and improve performance parameters of grains.