Cloning and Expression of a Nonribosomal Peptide Synthetase to Generate Blue Rose.

Rose has been entwined with human culture and history. "Blue rose" in English signifies unattainable hope or an impossible mission as it does not exist naturally and is not breedable regardless of centuries of effort by gardeners. With the knowledge of genes and enzymes involved in flower pigmentation and modern genetic technologies, synthetic biologists have undertaken the challenge of producing blue rose by engineering the complicated vacuolar flavonoid pigmentation pathway and resulted in a mauve-colored rose. A completely different strategy presented in this study employs a dual expression plasmid containing bacterial idgS and sfp genes. The holo-IdgS, activated by Sfp from its apo-form, is a functional nonribosomal peptide synthetase that converts l-glutamine into the blue pigment indigoidine. Expression of these genes upon petal injection with agro-infiltration solution generates blue-hued rose flowers. We envision that implementing this proof-of-concept with obligatory modifications may have tremendous impact in floriculture to achieve a historic milestone in rose breeding.