Development and Characterization of Highly Efficient Mimics of the Rice Growth Regulator Zaxinone for Basic Research and Agricultural Applications

Abstract

Carotenoids are the precursor of several plant hormones and signaling molecules, which play important roles in literally all aspects of plants’ life. Recently, we have identified zaxinone, an apocarotenoid formed by the carotenoid cleavage enzyme Zaxinone Synthase (ZAS), as a novel-signaling molecule required for rice growth and development. Investigation of a rice zas mutant and zaxinone treatment demonstrated that zaxinone is a negative regulator of SL biosynthesis, lowering SL content and alleviating infestation by the parasitic weed Striga. Now we further developed zaxinone-mimics with relatively simple structure that can be employed in fundamental research and large scale agriculture applications. Comparative studies demonstrated the two identified mimics of zaxinone (MiZaxs) appeared highly efficient that can cause a significant increase in root growth and biomass in wild type rice and restored the growth retardation and lowered SL content in the zas mutant. Treatment with MiZaxs significantly decreased SL release in wild-type rice and, accordingly, suppressed the infestation with the parasitic plant Striga.