Protein complexes involved in epigenetic regulation of transcription have evolved as molecular strategies to face environmental stress in plants. SAGA (Spt–Ada–Gcn5 Acetyltransferase) is a transcriptional co-activator complex that regulates numerous cellular processes through the coordination of multiple post-translational histone modifications, including acetylation, deubiquitination, and chromatin recognition. The diverse functions of the SAGA complex involve distinct modules that are highly conserved between yeast, flies, and mammals. In this review, the composition of the SAGA complex in plants is described and its role in gene expression regulation under stress conditions summarized. Some of these proteins are likely involved in the regulation of the inducible expression of genes under light, cold, drought, salt, and iron stress, although the functions of several of its components remain unknown.

The onset and rate of senescence influence key agronomical traits, including grain yield (GY). Our objective was to assess the relationships between stay-green and GY in a set of fourteen spring bread wheat (Triticum aestivum L.) genotypes with contrasting tolerance to water stress. Based on leaf chlorophyll content index (Chl) and normalized vegetation index (NDVI) measurements, the senescence dynamics at leaf and canopy levels, respectively, were quantified. Parameters describing the dynamics of senescence were examined in glasshouse and field experiments under well-watered (WW) and water-limited (WL) regimes, and they included the following stay-green traits: maximum NDVI or Chl near to anthesis (NDVI_max, Chl_max), the senescence rate (SR, rate), the area under curve (Area_NDVI, Area_Chl), and the time from anthesis to 10 (t_onset), 50 (t₅₀, X₅₀) and 90% (t₉₀) senescence. Our results revealed that specific stay-green traits were significantly different among genotypes and water regimes in both glasshouse and field experiments. GY was positively correlated with t_total (0.42), t_onset (0.62) and NDVI_dif (0.63). Under WL, NDVI_dif and NDVI_max correlated with GY (0.66–0.58), but only t₅₀ correlated with GY under WW (0.62), indicating that phenotyping of stay-green trait is a useful tool for tracking the dynamics of senescence in WW and WL environments.

The remarkable capacity of the generalist aphid Myzus persicae to resist most classes of pesticides, along with the environmental and human health risks associated with these agrochemicals, has necessitated the development of safer and greener solutions to control this agricultural pest. Oligogalacturonides (OGs) are pectin-derived molecules that can be isolated from fruit industry waste. OGs have been shown to efficiently stimulate plant defenses against pathogens such as Pseudomonas syringae and Botrytis cinerea. However, whether OGs confer resistance against phytophagous insects such as aphids remains unknown. Here, we treated Arabidopsis plants with OGs and recorded their effects on the feeding performance and population of M. persicae aphids. We also identified the defense mechanism triggered by OGs in plants through the analysis of gene expression and histological approaches. We found that OG treatments increased their resistance to M. persicae infestation by reducing the offspring number and feeding performance. Furthermore, this enhanced resistance was related to a substantial accumulation of callose and reactive oxygen species and activation of the salicylic acid signaling pathway.

Canopy temperature (CT) is widely used to assess crop water and heat status, but it is often recorded at a single hour, implicitly treating CT as a stable trait. Here, we show that canopy cooling is a dynamic phenotype whose expression depends on time of day, phenological stage, and environment. First, we monitored 184 spring wheat (Triticum aestivum L.) genotypes in two Mediterranean environments (fully irrigated vs. rainfed, contrasting atmospheric demand) using UAV-based thermal imaging. CT was measured six times per day (10:30–17:30 h) at four reproductive stages (anthesis, milk-grain, milk-dough, and dough), enabling quantification of diurnal plasticity, seasonal shifts, and environmental effects on canopy cooling. Second, repeated-measures mixed models confirmed that Location, Stage, and Time of day, and all interactions, were highly significant (p < 0.001). Variance-component analyses showed a strong genetic signal within each Stage × Environment combination, with 87.6–97.7% of total variance attributable to genotypic effects pooled across hours. Third, the optimal phenotyping window was context dependent: under rainfed conditions, genotypic discrimination consistently peaked around mid-afternoon (~15:00 h), whereas under irrigation, the optimal window shifted with stage (13:30–15:00 h). Genotype rankings were also markedly less stable across hours under rainfed conditions, indicating substantial within-day re-ranking as atmospheric demand increased. Finally, thermal exposure analyses showed that exceeding a physiologically relevant threshold (CT > 32 °C) depended strongly on time of day and stage; maximum CT captured short heat events missed by daily means. Clustering and alluvial analyses revealed frequent reclassification across stages, with only a small subset remaining consistently cooler, particularly under stress. Random regression of CT on vapor pressure deficit (VPD) indicated that CT–VPD sensitivity was largely environment-dependent and showed weak cross-environment correspondence (Spearman ρ = −0.166). Overall, single-time-point CT phenotyping provides an incomplete view of thermal status, underscoring the need for multi-temporal protocols and context-specific measurement windows for breeding and physiological interpretation under drought and heat.