Two Arabidopsis cytochrome P450 monooxygenases, CYP714A1 and CYP714A2, function redundantly in plant development through gibberellin deactivation

Abstract

SUMMARYThe rice gene ELONGATED UPPERMOST INTERNODE1 (EUI1) encodes a P450 monooxygenase that epoxidizes gibberellins (GAs) in a deactivation reaction. The Arabidopsis genome contains a tandemly duplicated gene pair ELA1 (CYP714A1) and ELA2 (CYP714A2) that encode EUI homologs. In this work, we dissected the functions of the two proteins. ELA1 and ELA2 exhibited overlapping yet distinct gene expression patterns. We showed that while single mutants of ELA1 or ELA2 exhibited no obvious morphological phenotype, simultaneous elimination of ELA1 and ELA2 expression in ELA1-RNAi/ela2 resulted in increased biomass and enlarged organs. By contrast, transgenic plants constitutively expressing either ELA1 or ELA2 were dwarfed, similar to those overexpressing the rice EUI gene. We also discovered that overexpression of ELA1 resulted in a severe dwarf phenotype, while overexpression of ELA2 gave rise to a breeding-favored semi-dwarf phenotype in rice. Consistent with the phenotypes, we found that the ELA1-RNAi/ela2 plants increased amounts of biologically active GAs that were decreased in the internodes of transgenic rice with ELA1 and ELA2 overexpression. In contrast, the precursor GA 12 slightly accumulated in the transgenic rice, and GA 19 highly accumulated in the ELA2 overexpression rice. Taken together, our study strongly suggests that the two Arabidopsis EUI homologs subtly regulate plant growth most likely through catalyzing deactivation of bioactive GAs similar to rice EUI. The two P450s may also function in early stages of the GA biosynthetic pathway. Our results also suggest that ELA2 could be an excellent tool for molecular breeding for high yield potential in cereal crops.

Rice HOX12 Regulates Panicle Exsertion by Directly Modulating the Expression of ELONGATED UPPERMOST INTERNODE1

“…Arabidopsis contains two closely related EUI1-like P450s, CYP714A1 and CYP714A2 (Zhang et al, 2011;Nomura et al, 2013). Overexpression of either CYP714A1 or CYP714A2 also results in dwarfism, which is similar to the phenotype of plants overexpressing the rice EUI1 gene (Zhang et al, 2011;Nomura et al, 2013). These results suggest that the regulation of internode elongation by EUI1 is evolutionarily conserved.…”

“…Transgenic Arabidopsis thaliana plants overexpressing rice CYP714B1 or CYP714B2 show semidwarfism . Arabidopsis contains two closely related EUI1-like P450s, CYP714A1 and CYP714A2 (Zhang et al, 2011;Nomura et al, 2013). Overexpression of either CYP714A1 or CYP714A2 also results in dwarfism, which is similar to the phenotype of plants overexpressing the rice EUI1 gene (Zhang et al, 2011;Nomura et al, 2013).…”

A mechanically sensitive cell layer regulates the physical properties of the Arabidopsis seed coat

“…We interrogated available transcriptional data generated in zou-4 mutant versus wild-type seeds at the mid torpedo stage of embryo development 22 to identify genes expressed in the seed coat (based on in silico data 1 ) and upregulated in the zou-4 mutant background. One such gene is At5g24910, which encodes the cytochrome p450 mono-oxygenase CYP714A1, also named EUI-LIKE P450 A1 (ELA1) 23,24 . Upregulation of ELA1 in zou mutants is confirmed using quantitative reverse transcription PCR (Fig.…”

Impacts of Diversification of Cytochrome P450 on Plant Metabolism

“…27) Arabidopsis CYP714A1 and CYP714A2 are redundant genes for GA inactivation. 28) These facts suggest that C-13 hydroxylation is an inactivation process of GA rather than a biosynthetic reaction.…”