An Evolutionarily Diverged CCD4 Enzyme Negatively Regulates Mesocotyl Elongation in Rice

ABSTRACT: Carotenoid cleavage dioxygenases (CCDs) catalyze the formation of phytohormones and other growth regulators, yet the CCD4 subfamily remains underexplored in cereals. The rice gene LOC_Os12g24800 has often been misannotated as nine-cis-epoxycarotenoid dioxygenase 2 (NCED2), implicating it in abscisic acid (ABA) biosynthesis. Here, we provide a definitive functional characterization of LOC_Os12g24800 and demonstrate that it encodes a CCD4-type enzyme, OsCCD4b, distinct from NCEDs. Using in vitro, in vivo, transgenic assays, and CRISPR/Cas9 and overexpressing lines, we show that OsCCD4b preferentially cleaves carotenoids at the C7′–C8′ double bond, producing C30 and C10 apocarotenoids, in contrast to the cleavage specificity of Arabidopsis CCD4. Moreover, we identify 3-OH-β-cyclocitral, a maj

INSTRUMENT(S): DESeq, Illumina Novaseq platform, Growthroom, Hisat2 v2.0.5, Illumina HiSeq 4000

ORGANISM(S): Oryza sativa

SUBMITTER: ABDUGAFFOR ABLAZOV 

PROVIDER: E-MTAB-16215 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress