Dear Editor,The physiological functions of carotenoids in plants go beyond their traditional roles as accessory light-harvesting pigments,natural colorants,and quenchers of triplet chlorophyll and singlet oxygen (1O2).Recent studies have indeed emphasized the functional role of molecules derived from carotenoids as phytohormones (Ruyter-Spira et al.,2013) or messengers in stress signaling pathways (Havaux,2014).In particular,chemical quenching of 1O2 by carotenoids within the photosystems involves oxidation of the carotenoid molecules,generating a variety of oxidized products (Ramel et al.,2012).β-Cyclocitral,a volatile C7 derivative of β-carotene,is one such molecule produced during high light stress,which was found to induce changes in the expression of 1O2-responsive genes (Ramel et al.,2012).