Bridging the Gap: From Photoperception to the Transcription Control of Genes Related to the Production of Phenolic Compounds

Abstract

Phenolic compounds are a group of secondary metabolites responsible for several processes in plants-these compounds are involved in plant-environment interactions (attraction of pollinators, repelling of herbivores, or chemotaxis of microbiota in soil), but also have antioxidative properties and are capable of binding heavy metals or screening ultraviolet radiation. Therefore, the accumulation of these compounds has to be precisely driven, which is ensured on several levels, but the most important aspect seems to be the control of the gene expression. Such transcriptional control requires the presence and activity of transcription factors (TFs) that are driven based on the current requirements of the plant. Two environmental factors mainly affect the accumulation of phenolic compounds-light and temperature. Because it is known that light perception occurs via the specialized sensors (photoreceptors) we decided to combine the biophysical knowledge about light perception in plants with the molecular biology-based knowledge about the transcription control of specific genes to bridge the gap between them. Our review offers insights into the regulation of genes related to phenolic compound production, strengthens understanding of plant responses to environmental cues, and opens avenues for manipulation of the total content and profile of phenolic compounds with potential applications in horticulture and food production.

Keywords: photoreceptors; radiation; temperature; transcription factors.

Figure 4

Mechanism of the transcription control of target genes by PhyB interaction with PIFs (scheme was adopted from [60] and modified).

Figure 1

General scheme of direct light perception in plants (simplified). The absorption of light turns inactive photoreceptors into active states and causes conformational changes, which differ between the different types of photoreceptors (in some cases monomerization occurs, while in others dimerization, and other changes in higher-order structures are documented). Such changes significantly affect the protein–protein interactions that follow and are different for different photoreceptors. The vast majority of activated photoreceptors interact with the COP/SPA/E3 ubiquitin ligase complex and therefore lead to the stabilization of transcription factors driving the gene expression of target genes. The remaining photoreceptors (zeitlupes and phototropins) interact with other proteins and do not contribute to the COP/SPA signaling.

Figure 2

Domain architecture and absorption ranges of the photoreceptors. This scheme represents each group of known plant photoreceptors with highlighted absorption ranges, domain architecture, and the corresponding part of the spectra these photoreceptors play a role in (adopted and modified based on publications [22,23,24,25]).

Figure 3

The mechanism of the photoreceptors sensing, signaling, and regeneration. For each plant photoreceptor, the basic mechanism of the photo sensing is indicated (it can be either monomerization, dimerization, or conformational changes), together with the light region that induced the active state of photoreceptors, and the signaling pathway where the light signal is further propagated (the related literature is cited in the text accompanying this scheme).

Figure 5

The simplified scheme of the transcriptional control of the genes related to the production of phenolic compounds (scheme was adopted from [112] and modified).