A new collaborative paper from TPB02 Schön/Avramova: Rate of ABA degradation is modulated by the gene ZmAbh4, thereby modulating water use efficiency, stomatal conductance, and carbon isotope discrimination in maize.
Natural alleles of the abscisic acid catabolism gene ZmAbh4 modulate water use efficiency and carbon isotope discrimination in maize.
The Plant Cell, 2022
Sonja Blankenagel, Stella Eggels, Monika Frey, Erwin Grill, Eva Bauer, Corinna Dawid, Alisdair R Fernie, Georg Haberer, Richard Hammerl, David Barbosa Medeiros, Milena Ouzunova, Thomas Presterl, Victoria Ruß, Rudi Schäufele, Urte Schlüter, Francois Tardieu, Claude Urbany, Sebastian Urzinger, Andreas P M Weber, Chris-Carolin Schön, Viktoriya Avramova.
Altering plant water use efficiency (WUE) is a promising approach for achieving sustainable crop production in changing climate scenarios. Here, we show that WUE can be tuned by alleles of a single gene discovered in elite maize (Zea mays) breeding material. Genetic dissection of a genomic region affecting WUE led to the identification of the gene ZmAbh4 as causative for the effect. CRISPR/Cas9-mediated ZmAbh4 inactivation increased WUE without growth reductions in well-watered conditions. ZmAbh4 encodes an enzyme that hydroxylates the phytohormone abscisic acid (ABA) and initiates its catabolism. Stomatal conductance is regulated by ABA and emerged as a major link between variation in WUE and discrimination against the heavy carbon isotope (?13C) during photosynthesis in the C4 crop maize. Changes in ?13C persisted in kernel material, which offers an easy-to-screen proxy for WUE. Our results establish a direct physiological and genetic link between WUE and ?13C through a single gene with potential applications in maize breeding.
