Cytochrome P450 metabolizing fatty acids in plants: characterization and physiological roles

Abstract

In plants, fatty acids (FA) are subjected to various types of oxygenation reactions. Products include hydroxyacids, as well as hydroperoxides, epoxides, aldehydes, ketones and α,ω‐diacids. Many of these reactions are catalysed by cytochrome P450s (P450s), which represent one of the largest superfamilies of proteins in plants. The existence of P450‐type metabolizing FA enzymes in plants was established approximately four decades ago in studies on the biosynthesis of lipid polyesters. Biochemical investigations have highlighted two major characteristics of P450s acting on FAs: (a) they can be inhibited by FA analogues carrying an acetylenic function, and (b) they can be enhanced by biotic and abiotic stress at the transcriptional level. Based on these properties, P450s capable of producing oxidized FA have been identified and characterized from various plant species. Until recently, the vast majority of characterized P450s acting on FAs belonged to the CYP86 and CYP94 families. In the past five years, rapid progress in the characterization of mutants in the model plant Arabidopsis thaliana has allowed the identification of such enzymes in many other P450 families (i.e. CYP703, CYP704, CYP709, CYP77, CYP74). The presence in a single species of distinct enzymes characterized by their own regulation and catalytic properties raised the question of their physiological meaning. Functional studies in A. thaliana have demonstrated the involvement of FA hydroxylases in the synthesis of the protective biopolymers cutin, suberin and sporopollenin. In addition, several lines of evidence discussed in this minireview are consistent with P450s metabolizing FAs in many aspects of plant biology, such as defence against pathogens and herbivores, development, catabolism or reproduction.

Cytochrome P450 CYP94B3 mediates catabolism and inactivation of the plant hormone jasmonoyl-L-isoleucine

“…Whereas Arabidopsis contains six CYP94s, the family has undergone significant expansion in other species; CYP94s comprise the largest non-A-type P450 family in soybean and rice, which have 14 and 18 members, respectively (27). CYP94 genes are conserved in dicots, monocots, and nonvascular plants (e.g., Physcomitrella patens), but not in photosynthetic aquatic organisms (20,28). This phylogenetic distribution highlights the importance of CYP94 in land plants and further suggests that pathways for jasmonate catabolism are conserved in evolution.…”

“…1A), we focused our attention on members of the CYP86 and CYP94 families of P450 that are well characterized for their role in fatty acid ω-hydroxylation (Fig. 1B) (19)(20)(21). Second, based on the kinetics of substrate (JA/JA-Ile) and product (12OH-JAs) accumulation during the wound response (11,13), we reasoned that genes encoding enzymes involved in JA-Ile turnover may be induced by wounding.…”

Apoplastic Diffusion Barriers in Arabidopsis

“…These oxygenated FAs are generated by the enzyme-catalyzed insertion of oxygen into the carbon chain, which is catalyzed by cytochrome P450 oxygenases (P450s). The majority of FA hydroxylases belong to the CYP86 and CYP94 families of P450s; however, FA hydroxylases have recently been identified in other P450 families, including CYP77, CYP703, CYP704 and others (Pinot and Beisson, 2011). Thus, P450 genes represent prime candidates for involvement in polyester biosynthesis.…”

Diet of Arbuscular Mycorrhizal Fungi: Bread and Butter?

“…Transfer of FAs from chloroplasts to the ER can be facilitated by direct contact sites between these two compartments [83]. In the ER, the FAs are further processed by oxidation involving cytochrome P450/CYP enzymes to yield diOH-C16-CoA (and related products) [84], followed by condensation with glycerol-3-phosphate by an sn2-specific glycerol-3-phosphate acyl transferase (sn2-GPAT) to produce 2-monoacyl glycerol (2-MAG) [85,86]. 2-MAG is exported into the apoplast by ABCG transporters [87].…”