Impact of Environmental Factors on Stilbene Biosynthesis

Abstract

Stilbenes are a small family of polyphenolic secondary metabolites that can be found in several distantly related plant species. These compounds act as phytoalexins, playing a crucial role in plant defense against phytopathogens, as well as being involved in the adaptation of plants to abiotic environmental factors. Among stilbenes, trans-resveratrol is certainly the most popular and extensively studied for its health properties. In recent years, an increasing number of stilbene compounds were subjected to investigations concerning their bioactivity. This review presents the most updated knowledge of the stilbene biosynthetic pathway, also focusing on the role of several environmental factors in eliciting stilbenes biosynthesis. The effects of ultraviolet radiation, visible light, ultrasonication, mechanical stress, salt stress, drought, temperature, ozone, and biotic stress are reviewed in the context of enhancing stilbene biosynthesis, both in planta and in plant cell and organ cultures. This knowledge may shed some light on stilbene biological roles and represents a useful tool to increase the accumulation of these valuable compounds.

Keywords: biosynthetic pathway; environmental factors; phenylpropanoid pathway; phytoalexins; pinosylvin synthase; polyphenols; resveratrol synthase; secondary metabolites; stilbene biosynthesis; stilbene synthase; stilbenes.

Figure 1

Chemical structures of common stilbene monomer derivatives. (OGlu) O-β-D-glucopyranoside.

Figure 2

Stilbene biosynthesis in plants. (PAL) phenylalanine ammonia-lyase; (PTAL) bifunctional L-phenylalanine/L-tyrosine ammonia-lyase; (C4H) cinnamate 4-hydroxylase; (4CL) 4-coumarate:CoA ligase; (CNL) cinnamate: CoA ligase; (STS) stilbene synthase; (RS) resveratrol synthase; (PS) pinosylvin synthase.

Figure 3

Examples of reactions catalyzed by stilbene synthase enzymes. (A) Conversion of p-coumaroyl-CoA into t-resveratrol by resveratrol (RS) synthase (or trihydroxystilbene synthase I). (B) Conversion of cinnamoyl-CoA into t-pinosylvin by pinosylvin synthase (PS). (C) Conversion of dihydro-cinnamoyl-CoA into dihydropinosylvin by dihydro-pinosylvin synthase (DPS). (D) Conversion of caffeoyl-CoA into t-piceatannol, probably catalyzed by PS.

Figure 4

Reactions catalyzed by chalcone synthase (CHS) and stilbene synthase (STS) to produce naringenin chalcone and resveratrol, respectively. R = H phenylalanine (Phe); R = OH tyrosine (Tyr). Double arrows indicate multiple steps in the biosynthetic pathway.

Figure 5

Common examples of stilbene glucosylation.

Figure 6

Common methylated stilbenes are biosynthetically derived from pinosylvin, resveratrol, and piceatannol.

Figure 7

Major prenylated stilbenoids contained in peanuts.

Figure 8

Of resveratrol trimers and tetramers in grapevine: (1) trans-resveratrol; (2) (E and Z) ε-viniferin/ω-viniferin; (3) pallidol; (4) caraphenol B; (5) δ-viniferin (E and Z); (6) α-viniferin; (7) isohopeaphenol; (8) E-miyabenol C; (9) Z-miyabenol C; (10) vaticanol C isomer; and (11) ampelopsin H [181,182].