Auxin, Cytokinin and Ab sei sic Acid

Abstract Auxin, cytokinin, and abscisic acid (ABA) are important plant hormones that regulate many growth and developmental processes. In recent years, a number of genes involved in the metabolic and signaling pathways for auxin, cytokinin and ABA have been cloned and characterized. With organ-and tissue-specific or conditionally active gene promoters, it has become possible to manipulate concentrations of plant hormones in planta to create commercially desirable traits. Seedless fruit production and the extension of shelf life of green produce and ornamental plants are two successful examples of manipulating concentrations of these hormones in planta. In this review, we will focus our discussion on the effects of the over-or under-expression of genes involved in the biosynthetic and catabolic pathways of these hormones with an emphasis on their potential applications in ornamental crops.