CYP72A enzymes catalyse 13-hydrolyzation of gibberellins
Bioactive gibberellins (GAs, diterpenes) are essential hormones in land plants, controlling many aspects of plant growth and developments. In flowering plants, 13-OH (low bioactivity; such as GA1) and 13-H GAs (high bioactivity; such as GA4) frequently coexist. However, the bona fide GA 13-hydroxylase and its physiological functions in Arabidopsis remain unknown. Here, we report that novel cytochrome P450 genes (CYP72A9 and its homologs) encode active GA 13- hydroxylases in Brassicaceae plants. CYP72A9-overexpressing plants exhibited semi-dwarfism, which was caused by significant reduction in GA4 levels. Biochemical assays revealed that recombinant CYP72A9 protein catalyzed the conversion from 13-H GAs to the corresponding 13-OH GAs. CYP72A9 was expressed predominantly in developing seeds in Arabidopsis. Freshly harvested seeds of cyp72a9 mutants germinated more quickly than wild-type, while long-term storage and stratification-treated seeds did not. The evolutionary origin of GA 13- oxidases from the CYP72A subfamily also was investigated and discussed here.
This is a manuscript of an article published as He, Juan, Qingwen Chen, Peiyong Xin, Jia Yuan, Yihua Ma, Xuemei Wang, Meimei Xu, Jinfang Chu, Reuben J. Peters, and Guodong Wang. "CYP72A enzymes catalyse 13-hydrolyzation of gibberellins." Nature plants (2019). doi: 10.1038/s41477-019-0511-z. Posted with permission.