Hydroxycinnamoyltransferases Involved in the Accumulation of Caffeic Acid Esters in Gametophytes and Sporophytes of Equisetum arvense

Abstract

Four hydroxycinnamoyltransferases from Equisefum arvense L. were studied that catalyze the formation of mono-Ocaffeoylmeso-tartrate, di-O-caffeoyl-meso-tartrate, 5-Ocaffeoylshikimate (dactylifrate), and 5-Ocaffeoylquinate (chlorogenate). l h e enzymes were classified as coenzyme A (COA)-ester-dependent acyltransferases (EC 2.3.1), i.e. hydroxycinnamoyl-CoAmeso-tartrate hydroxycinnamoyltransferase (CTT), hydroxycinnamoyl-CoA:caffeoyl-meso-tartrate hydroxycinnamoyltransferase (CCT), hydroxycinnamoyl-CoAshikimate hydroxycinnamoyltransferase (CST), and hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase. The CTT, CCT, and CST were partially purified and separated from E. arvense gametophytes by hydrophobic interaction chromatography on Fractogel TSK Butyl-650 followed by molecular exclusion on fast protein liquid chromatography-Superdex-75 with 87-, 62-, and 130-fold enrichments and 12, 8, and 11% yields, respectively. The enzyme activities obtained with caffeoyl-COA were 95 (CTT), 74 (CCT), and 200 pkat (CST) kg-' protein. The apparent native relative molecular weight values were found t o be approximately 45,000 (CTT), 52,000 (CCT), and 50,000 (CST). Each enzyme showed highest activities at p H 7.5, the CCT and CST i n lris-HCI (1.2 and 1.0 M) and the CTT in imidazole-HCI (1.25 M). Enzyme activities were stimulated more than 3-fold by 1 O0 mM ascorbate. l h e apparent energies of activation (kilojoules mol-') were calculated t o be 56 (CTT), 69 (CST), and 76 (CCT). The enzymes accepted cinnamoyl-COA and various hydroxycinnamoyl-CoAs. The time course of the transferase activities along with that of a fourth one, hydroxycinnamoyl-CoA:quinate hydroxycinnamoyltransferase, and the pattern of product accumulation were determined during a 1 -year growth period of the E. arvense sporophytes.The sterile and fertile sporophytes of Equisetum arvense (horsetail) and some other Equisetum species accumulate a highly complex pattern of phenolic compounds, i.e. various flavonoids, styrylpyrone glucosides, and caffeic acid esters (Veit et al., 1995). In contrast, the gametophytes of E. arvense lack any flavonoids but accumulate styrylpyrone glucosides and caffeic acid esters. The latter are the most widespread hydroxycinnamic acid conjugates in plants (Merlgaard and Ravn, 1988 ( Matern and Kneusel, 1988). Recently, we elucidated the structures of caffeic acid esters in E. arvense, a tartrate diester and a shikimate monoester (Veit et al., 1991b(Veit et al., , 1992. Whereas the shikimate ester (5-O-caffeoylshikimate = dactylifrate) seems to be widespread among members of the Equisetaceae, along with a quinate ester (5-0-caffeoylquinate = chlorogenate), the occurrence of the tartrate ester is characteristic for E. arvense (Veit et al., 1992). These caffeic acid esters show, in contrast to the flavonoids and styrylpyrones, transient accumulation patterns in the sporophytes with high concentrations in spring decreasing to low amounts until the autumn months (Veit et al., 1991b;Weidner et al., 1991).As part of our studies on the e...

Environmental and developmental effects on the biosynthesis of UV‐B screening pigments in Scots pine (Pinus sylvestris L.) needles

“…Rye primary leaves responded most sensitively within 4 d after emerging from the coleoptile (Reuber et al 1996;Burchard, Bilger & Weissenböck 2000), and UV-B-dependent flavonoid accumulation in Arabidopsis was restricted to the early stages of leaf development (Lois 1994). HCT activities, involved in phytoalexin biosynthesis, were also developmentdependent in various systems, for example, wheat coleoptiles (Louis & Negrel 1991) and Equisetum sporophytes (Hohlfeld, Veit & Strack 1996).…”

Chicoric acid: chemistry, distribution, and production

“…Pure chicoric acid is a white powder (Synoradzki et al, 2005; personal observation), and now available as a purified standard via numerous chemical companies (e.g., Cerilliant Chemical Company, Indofine Chemical Company, Inc., Sigma-Aldrich Co, LLC, etc.). The most abundant natural form is L-chicoric acid [i.e., (-)-chicoric acid, 2,3-dicaffeoyl-L-tartaric acid, 2,3- O -dicaffeoyltartaric acid, 2R,3R- O -dicaffeoyltartaric acid, or di- E -caffeoyl-(2R-3R)-(-)-tartaric acid] and has been reported in the majority of the plants listed in Table 1, but the stereoisomer meso -chicoric acid (i.e., dicaffeoyl- meso -tartaric acid or di- E -caffeoyl-(2R-3S)-(-)-tartaric acid) has also been reported at a lesser levels in horsetail sprouts ( Equisetum arvense L.) (Veit et al, 1991, 1992; Hohlfeld et al, 1996), iceberg lettuce ( Lactuca sativa L.) (Baur et al, 2004; Luna et al, 2012), and purple coneflower ( Echinacea purpurea L. Monech) (Perry et al, 2001). …”

“…Snook et al (1994) showed that a small amount of L-chicoric acid in peanut leaf terminal methanol extract isomerized into meso -chicoric acid at room temperature. Although three accounts from a single research group confirmed by Nuclear Magnetic Resonance (NMR) the tartaric acid structure of purified meso -chicoric acid of horsetail barren sprouts (Veit et al, 1991, 1992; Hohlfeld et al, 1996), an independent report found L-chicoric acid, but no meso -chicoric acid in horsetail (Hasegawa and Taneyama, 1973). …”

Identification and Characterization of Five BAHD Acyltransferases Involved in Hydroxycinnamoyl Ester Metabolism in Chicory

“…A S. lycopersicum HQT was also shown to be involved in the formation of diCQA from CQA ( Moglia et al, 2014 ). In A. glabrata and Equisetum arvense , it was shown that CTA is synthesized through condensation of a caffeoyl-CoA with tartaric acid which is a typical mechanism of the BAHD family members ( Hohlfeld et al, 1996 ; Sullivan, 2014 ). Furthermore chicoric acid was demonstrated in vitro to be synthesized by transfer of a caffeoyl moiety of caffeoyl-CoA to CTA in E. arvense ( Hohlfeld et al, 1996 ).…”