Carotenoid cleavage dioxygenases (CCDs) form hormones and signaling molecules. Here we show that a member of an overlooked plant CCD subfamily from rice, that we name Zaxinone Synthase (ZAS), can produce zaxinone, a novel apocarotenoid metabolite in vitro. Loss-of-function mutants (zas) contain less zaxinone, exhibit retarded growth and showed elevated levels of strigolactones (SLs), a hormone that determines plant architecture, mediates mycorrhization and facilitates infestation by root parasitic weeds, such as Striga spp. Application of zaxinone can rescue zas phenotypes, decrease SL content and release and promote root growth in wild-type seedlings. In conclusion, we show that zaxinone is a key regulator of rice development and biotic interactions and has potential for increasing crop growth and combating Striga, a severe threat to global food security.
Bibliographical noteFunding Information:
This work was supported by baseline funding and Competitive Research Grant (CRG2017) given to S. A-B. from King Abdullah University of Science and Technology and by Green-Rice (FACCE-JPI ERA-NET + Agriculture food security and climate change) grant given to P.B. and 60% Projects (University of Torino) given to L.L. We thank Dr. Giampiero Valè and Dr. Gabriele Orasen for the support provided for the field experiment and grains collection at CRA-RIS of Vercelli, Dr. Tadao Asami for providing D6−5-deoxystrigol standard, Anthony Boisseau and Dragos-Bogdan Ilies for technical support in the in vitro assays.
© 2019, The Author(s).
ASJC Scopus subject areas
- General Chemistry
- General Biochemistry, Genetics and Molecular Biology
- General Physics and Astronomy