The cytochrome P450 CYP77A4 is involved in auxin-mediated patterning of the Arabidopsis thaliana embryo

• Published in: Development (Cambridge) Vol. 145; no. 17
• Main Authors: Kawade, Kensuke, Li, Yimeng, Koga, Hiroyuki, Sawada, Yuji, Okamoto, Mami, Kuwahara, Ayuko, Tsukaya, Hirokazu, Hirai, Masami Yokota
• Format: Journal Article
• Language: English
• Published: England 01.09.2018
• Subjects: Arabidopsis thaliana; Quantitative phenome analysis; Auxin distribution; Cytochrome P450; Embryonic patterning; Fatty-acid epoxidase
• ISSN: 0950-1991; 1477-9129
• DOI: 10.1242/dev.168369

Metabolism often plays an important role in developmental control, in addition to supporting basal physiological requirements. However, our understanding of this interaction remains limited. Here, we performed quantitative phenome analysis of cytochrome P450 mutants to identify a novel interaction between development and metabolism. We found that mutants exhibit specific defects in cotyledon development, including asymmetric positioning and cup-shaped morphology, which could be rescued by introducing the gene. Microscopy revealed that the abnormal patterning was detected at least from the 8-cell stage of the embryos. We next analysed auxin distribution in mutant embryos, as the phenotypes resembled those of auxin-related mutants. We found that the auxin response pattern was severely perturbed in the embryos owing to an aberrant distribution of the auxin efflux carrier PIN1. CYP77A4 intracellularly localised to the endoplasmic reticulum, which is consistent with the notion that this enzyme acts as an epoxidase of unsaturated fatty acids in the microsomal fraction. We propose that the CYP77A4-dependent metabolic pathway is an essential element for the establishment of polarity in plant embryos.