Photosynthetically active radiation (PAR) is an important environmental cue inducing the production of many secondary metabolites involved in plant oxidative stress avoidance and tolerance. To examine the complex role of PAR irradiance and specific spectral components on the accumulation of phenolic compounds (PheCs), we acclimated spring barley (Hordeum vulgare) to different spectral qualities (white, blue, green, red) at three irradiances (100, 200, 400 µmol m⁻² s⁻¹). We confirmed that blue light irradiance is essential for the accumulation of PheCs in secondary barley leaves (in UV-lacking conditions), which underpins the importance of photoreceptor signals (especially cryptochrome). Increasing blue light irradiance most effectively induced the accumulation of B-dihydroxylated flavonoids, probably due to the significantly enhanced expression of the F3′H gene. These changes in PheC metabolism led to a steeper increase in antioxidant activity than epidermal UV-A shielding in leaf extracts containing PheCs. In addition, we examined the possible role of miRNAs in the complex regulation of gene expression related to PheC biosynthesis.

Accumulation and metabolic profile of phenolic compounds (PheCs; serving as UV-screening pigments and antioxidants) as well as carbon fixation rate (A_n) and plant growth are sensitive to irradiance and temperature. Since these factors are naturally co-acting in the environment, it is worthy to study the combined effects of these environmental factors to assess their possible physiological consequences. We investigated how low and high irradiance in combination with different temperatures modify the metabolic profile of PheCs and expression of genes involved in the antioxidative enzyme and PheCs biosynthesis, in relation to photosynthetic activity and availability of non-structural carbohydrates (NSC) in spring barley seedlings. High irradiance positively affected A_n, NSC, PheCs content, and antioxidant activity (AOX). High temperature led to decreased A_n, NSC, and increased dark respiration, whilst low temperature was accompanied by reduction of UV-A shielding but increase of PheCs content and AOX. Besides that, irradiance and temperature caused changes in the metabolic profile of PheCs, particularly alteration in homoorientin/isovitexin derivatives ratio, possibly related to demands on AOX-based protection. Moreover, we also observed changes in the ratio of sinapoyl-/feruloyl- acylated flavonoids, the function of which is not yet known. The data also strongly suggested that the NSC content may support the PheCs production.

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.

The correct tools for characterization of histone proteoforms are essential for deciphering plant epigenetic mechanisms and their subsequent application in biotechnology. Insights into the epigenetic landscape of plant chromatin can be advanced using bottom-up proteomics. MS analysis of histone peptides relies on careful sample preparation, including chemical derivatization of amine groups prior to MS to improve their chromatographic behaviour during nanoHPLC separation. Characterizing histones in plant tissues remains especially challenging due to the presence of diverse, species-specific compounds that interfere with MS analysis. In this study, we evaluated the impact of different protocols for the preparation of histones from maize (Zea mays) leaves on the quality of MS data. We were able to enhance the MS-based plant histone analysis protocol by combining chemical derivatization using trimethylacetic anhydride with enzymatic digestion with a novel protease, Arg-C Ultra. In addition, fluorescence-assisted cell sorting proved to be effective in isolating pure histone samples without the need for protein purification by precipitation. Our proposed new workflows produce highly pure histone extracts that are suitable for quantitative analysis of post-translational modifications and variant composition. They therefore offer a powerful tool for investigating epigenetic patterns and their dynamics in agriculturally important crops.

Due to the ongoing climate change plants face multiple stress factors (mainly the abiotic ones) simultaneously, which means that the reduced yields of critical crops (including wheat, rice, or barley) can be expected. Therefore, our understanding of the light and temperature sensing mechanisms and related signaling is of primary importance. Herein we present a review focused on the direct sensing (ensured via photoreceptors) of light, which is the main abiotic factor driving the development, phenology, and especially resistance against oxidative stress via the increased accumulation of protective metabolites of crops. Thus, in the following text, special attention is paid to the description of the plant photoreceptors, their mode of action, ranges of perception, and related signaling pathways leading to the activation of target transcription factors. These finally lead to alterations in the expression of target genes related to photoprotection. Due to the focus of our research, genes related to the production of phenolic compounds (PheCs) were selected as a representative group of target genes having a UV-screening, and antioxidative function meaning that their activation and activity of resulting proteins can significantly contribute to the increased tolerance of plants against stress cues.

Temperature plays a pivotal role in defining the distribution of species and the fitness of individuals within species' ranges. Phenotypic plasticity can allow individuals to cope with varying environmental conditions, including rapid climate change. Populations at range edges experience more variable conditions than core populations and thus are hypothesized to exhibit higher thermal plasticity. However, as the strength of plasticity often varies between individuals, it can also differ among local populations at range edges. We studied the extent of and variation in thermal plasticity for several traits within and between populations of the perennial herb Plantago lanceolata L. (Plantaginaceae) at its northern range edge. We sampled seeds from nine sites within a 50 × 50 km region and grew them under three temperature regimes in a greenhouse. We measured traits related to size, flowering, pathogen responses, and inflorescence pigmentation. We expected to find higher plasticity in traits less strongly connected to fitness and that differences between individuals would outweigh differences between populations in underpinning this variation in plasticity. Our results show thermal plasticity in leaf size and abundance, flowering probability and abundance, and pigmentation. Notably, we also found increased pathogen symptoms and higher infection rates of one of two viruses screened, highlighting the potential for changes in pathogen sensitivity and exposure under climate change. Importantly, in all traits but flower abundance, more variation in plasticity was attributable to differences within populations than between populations. Although this contribution was small in magnitude compared to thermal effects on traits, the higher intra‐ versus interpopulation variation in plasticity suggests that differences between individuals provide most of the variation in thermal plasticity, which may be driven by small‐scale variations in habitat conditions, highlighting the need for conservation strategies that consider microhabitat variation to support short‐term adaptive responses to thermal variability.