Saffron: Its Phytochemistry, Developmental Processes, and Biotechnological Prospects

The present state of knowledge concerning developmental processes and the secondary metabolism of saffron, Crocus sativus L. (Iridaceae), along with the genes involved in these processes so far known, is reviewed. Flowers and corms constitute the most valuable parts of saffron. Corm and flower development are two key aspects to be studied in saffron to increase the yield and quality of the spice, to raise its reproductive rate, and to implement new production systems. Important knowledge about the physiology of flowering and vegetative growth has been acquired in recent years, but there is still only limited information on molecular mechanisms controlling these processes. Although some genes involved in flower formation and meristem transition in other species have been isolated in saffron, the role of these genes in this species awaits further progress. Also, genes related with the synthesis pathway of abscisic acid and strigolactones, growth regulators related with bud endodormancy and apical dominance (paradormancy), have been isolated. However, the in-depth understanding of these processes as well as of corm development is far from being achieved. By contrast, saffron phytochemicals have been widely studied. The different flower tissues and the corm have been proved to be an important source of phytochemicals with pharmacological properties. The biotechnological prospects for saffron are here reviewed on the basis of the discovery of the enzymes involved in key aspects of saffron secondary metabolism, and we also analyze the possibility of transferring current knowledge about flowering and vegetative propagation in model species to the Crocus genus.