Ectopic expression of human apolipoprotein D in Arabidopsis plants lacking chloroplastic lipocalin partially rescues sensitivity to drought and oxidative stress

The chloroplastic lipocalin (LCNP) is induced in response to various abiotic stresses including high light, dehydration and low temperature. It contributes protection against oxidative damage promoted by adverse conditions preventing accumulation of fatty acid hydroperoxides lipid peroxidation. In contrast animal lipocalins, LCNP poorly characterized the molecular mechanism which it exerts protective effects during stress largely unknown. considered ortholog human apolipoprotein D (APOD), a protein whose antioxidant function has been characterized. Here, we investigated whether APOD could functionally replace Arabidopsis thaliana. We introduced cDNA fused chloroplast transit peptide encoding sequence an KO mutant line challenged transgenic plants with different stresses. demonstrated that expression can partially compensate for lack plastid lipocalin. results are consistent conserved under stressful conditions. However, if obtained drought point effect constitutive lacking LCNP, this not as effective conferred overexpression. Moreover, when investigating thylakoids after light at temperature, appeared contribute qH, slowly reversible form non-photochemical chlorophyll fluorescence quenching, described LCNP. This work provides base understanding underlying function.