ABSTRACT
More than 600 carotenoids and carotenoid-derived species have been found in the chloroplasts of plants and also of other organisms, including algae, fungi, and bacteria. In plants, this group of 40-C polyene molecules (tetraterpenes) are synthesized and accumulated in plastids, where they fulfill a multitude of roles: from the ecological function (e.g., attraction of pollinators) to the cellular level (e.g., retrograde signaling) (Havaux 2013). Despite this astonishing functional and structural diversity, the chloroplast pigment composition of the green lineage of the plant kingdom (which includes green algae, hornworts, liverworts, mosses, and vascular plants) is remarkably constant. Thus, with a few exceptions, functional chloroplasts from all species analyzed so far contain six ubiquitous carotenoids: neoxanthin (Neo), violaxanthin (Vio), antheraxanthin (Ant), zeaxanthin (Zea), lutein (L), and (3-carotene ((3-Car), together with the main two chlorophylls, Chl a and Chl b (Young et al. 1997; Esteban et al. 2015).
