Transcription of protein-encoding genes starts with forming a pre-initiation complex comprised of RNA polymerase II and several general transcription factors. To activate gene expression, transcription factors must overcome repressive chromatin structure, which is accomplished with multiprotein complexes. One such complex, SAGA, modifies the nucleosomal histones through acetylation and other histone modifications. A prototypical histone acetyltransferase (HAT) known as general control non-repressed protein 5 (GCN5), was defined biochemically as the first transcription-linked HAT with specificity for histone H3 lysine 14. In this review, we analyze the components of the putative plant SAGA complex during plant evolution, and current knowledge on the biological role of the key components of the HAT module, GCN5 and ADA2b in plants, will be summarized.

Analysis of table olives microbiome using next-generation sequencing has enriched the available information about the microbial community composition of this popular fermented food. In this study, 16S and 18S rRNA sequencing was performed on table olives of five Greek popular cultivars, Halkidikis, Thassou, Kalamon, Amfissis, and Konservolia, fermented either by Greek style (in brine or salt-drying) or by Spanish style, in order to evaluate their microbial communities. Moreover, analytical methods were used to evaluate their biochemical properties. The prevailing bacterial species of all olives belonged to Lactobacillaceae, Leuconostocaceae, and Erwiniaceae families, while the most abundant yeasts were of the Pichiaceae family. Principal coordinates analysis showed a clustering of samples cured by salt-drying and of samples stored in brine, regardless of their cultivar. The biochemical evaluation of total phenol content, antioxidant activity, hydroxytyrosol, oleuropein, oleocanthal, and oleacein showed that salt-dried olives had low amounts of hydroxytyrosol, while Spanish-style green olives had the highest amounts of oleocanthal. All the other values exhibited various patterns, implying that more than one factor affects the biochemical identity of the final product. The protocols applied in this study can provide useful insights for the final product, both for the producers and the consumers.

Olive tree growth and reproduction are severely affected by temperature extremes, compromising fruit yield. In that aspect, the olive varieties “Koroneiki” and “Mastoidis” were employed in a mild cold stress experiment, imitating night frost incidents to assess their biochemical, physiological and reproductive functions in relation to genotype. The physiological performance of the stressed plants was not significantly altered, suggesting that both cultivars were well adapted to mild cold night stress. The biochemical response of the plants, regarding antioxidant enzymes, H₂O₂ and TBARS accumulation, confirmed that both cultivars could cope with the stress applied. The mRNA levels of the PPO gene, which participates in hydroxytyrosol biosynthesis and plant defense, were elevated after 24-h stress at 0 °C, in both cultivars with “Mastoidis” plants exhibiting higher levels for a longer period. Three more genes involved in hydroxytyrosol biosynthesis upregulated their expression levels as a response to cold stress. The numerous plant phenology aspects measured reinforced the conclusion that both cultivars responded to the stress applied. The results of the present study may contribute to better understanding olive tree adaptive responses to low temperature events, an abiotic stress condition that is often present in an open plantation, thus assisting farmers on breeding and cultivar selection.

Research has highlighted the nutritional benefits of ancient grains, especially emmer (Triticum turgidum ssp. dicoccum) and einkorn (Triticum monococcum), compared to modern varieties of common and durum wheat, focusing on their higher levels of antioxidants and phytochemicals. In this study, grains from old Greek landraces of einkorn, emmer, durum and common wheat were compared to modern wheat cultivars, as well as barley, oats and rye grains, to investigate their unique genetic profile and nutritional properties. Genotyping of Triticum species was performed using SSR markers, which allowed differentiation up to cultivar level. Nutritional factors like the total content of bound and free polyphenols, flavonoids, antioxidant activity and fatty acid profile were assessed. The results showed that emmer and einkorn had the highest total polyphenol, flavonoid and mono-unsaturated fatty acids content, as well as higher antioxidant activity than common and durum wheat. Local landraces of common and durum wheat also exhibited higher values than commercial cultivars. The results of this study demonstrate the high nutritional value of ancient wheat varieties. Many of these cultivars have been put aside by more productive, yet with lower qualitative characteristics, commercial cultivars, underlining the importance of maintaining sustainable agricultural practices to ensure their continued cultivation.