Global warming and increasing water scarcity pose major challenges to agriculture, emphasizing the need to translate stress-biology insights into the development of drought-resilient cultivars. In this study, we evaluated a panel of six diverse sorghum ( Sorghum bicolor) accessions grown under field-imposed drought conditions in central Arizona, integrating physiological, transcriptomic, and oxidative stress measurements over a seven-week period. Using network analyses informed by co-expression correlations, transcription factor (TF) binding motif signatures, and protein–protein interactions, we identified a drought-associated module strongly correlated with photosynthetic capacity. This module contained a stress-responsive TF, SbDof8 (referred to here as SbCDF2/3-like, or SbCDF2/3L), as a highly connected hub gene, and CDF2/3-associated binding motifs were over-represented in the promoters of co-expressed module members. These co-expressed members were enriched for stress response, metabolic, and photosynthesis-related processes, and consistently maintain higher expression under drought in tolerant compared to sensitive accessions. Analysis of an independent sorghum drought time-course dataset comprised of two unique accessions revealed concordant expression patterns of SbCDF2/3L and photosynthesis-associated module genes between drought-tolerant and drought-sensitive genotypes, reinforcing the robustness of this regulatory module. Together, our results highlight a subset of photosystem I (PSI)–related genes, including light-harvesting proteins, PSI subunits, and importantly, a potential drought responsive transcriptional regulator that are collectively upregulated in resilient accessions as a means of coping with drought response. These data highlight promising breeding targets for improving drought resilience and biomass productivity in sorghum under field conditions.

Climate change increases the frequency and severity of heatwaves that negatively affect plant survival and productivity. To investigate the possibility that heat stress primes plants and their offspring for future exposure, we exposed successive generations of Arabidopsis thaliana to severe heatwave conditions. Heat-primed offspring had a higher seed production after exposure to heat stress. DNA methylation mutants were more sensitive and showed no priming effect, whereas demethylation mutants showed the opposite response, confirming the involvement of DNA methylation in the response to the treatments. Consistently, bisulfite sequencing showed a global hypermethylation of genomic, conversely mitochondrial DNA revealed hypomethylation in response to heat. mRNA sequencing indicated that priming particularly affected genes related to the mitochondrial energy system and oxidative stress responses. Consistently, under heat conditions respiration rates and antioxidant enzymes activities (APX, POX, CAT, DHAR and MDHAR) were less increased, whereas soluble sugar and tocopherol levels were higher in primed plants. Under heat conditions membrane peroxidation (MDA) and protein carbonylation levels of primed plants were significantly lower, correlating with a lower increase of electrolyte leakage. These results demonstrate that heat stress induces heritable epigenetic changes involving DNA methylation affecting respiration and antioxidant activities enhancing the protection from oxidative damage. This increases the resilience of the plant and its progeny and affects our predictions of climate change responses of plants.

To understand the growth response to drought, we performed a proteomics study in the leaf growth zone of maize (Zea mays L.) seedlings and functionally characterized the role of starch biosynthesis in the regulation of growth, photosynthesis and antioxidant capacity, using the shrunken2 mutant (sh2), defective in ADP-glucose pyrophosphorylase. Drought induced differential expression of 284 proteins overrepresented for photosynthesis, amino acids, sugar and starch metabolism, and redox-regulation. Changes in protein levels correlated with enzyme activities (increased ATP synthase, cysteine synthase, starch synthase, RuBisCo, peroxiredoxin, glutaredoxin, thioredoxin and decreased triosephosphate isomerase, ferredoxin, cellulose synthase activities, respectively) and metabolite concentrations (increased ATP, cysteine, glycine, serine, starch, proline and decreased cellulose levels). The sh2 mutant had a reduced ability to increase starch levels under drought conditions, causing soluble sugar starvation at the end of the night and impaired leaf growth. Increased RuBisCo activity and pigment concentrations observed in WT in response to drought were lacking in the mutant, which suffered more oxidative damage and recovered more slowly after re-watering. These results demonstrate that starch biosynthesis plays a crucial role in maintaining leaf growth under drought stress and facilitates enhanced carbon acquisition upon recovery.

Ocean acidification is impacting marine life all over the world. Understanding how species are able to cope with the changes of seawater carbonate chemistry represents a challenging issue. We addressed this topic using underwater CO2 vents that naturally acidify some marine areas occurring off the island of Ischia. There, the brown alga Sargassum vulgare dominates the most acidified area, showing a pH value of 6.7, comparable to future, i.e. 2300, acidification scenarios. The novelty of the present study is the characterization of the S. vulgare proteome as response to ocean acidification. A total of 584 and 535 proteins were characterized in populations grown on current pH and acidified sites, respectively. 507 Proteins were significantly expressed in samples from both sites: 41 proteins were either up-regulated or exclusively present under acidified conditions, whereas 108 proteins were either down-regulated in the acidified site or present only under control conditions. Functionally, a decrease in proteins related to transcription and translation, and ER/Golgi trafficking and vesicular transport was observed under acidification. The up-regulated proteins are involved in the photosynthetic process and stress response. In addition, aminoacids metabolism was affected, which was reflected in their levels. Analyses of other metabolites revealed variations in the levels of some fatty acids and phenols. Overall, the results obtained by proteomics and metabolites analysis, integrated with previous transcriptomic, physiological and biochemical studies, have allowed to delineate the molecular strategies adopted by S. vulgare to grow in future acidified environments.