Potato (Solanum tuberosum) is highly water and space efficient but susceptible to abiotic stresses such as heat, drought, and flooding, which are severely exacerbated by climate change. Our understanding of crop acclimation to abiotic stress, however, remains limited. Here, we present a comprehensive molecular and physiological high-throughput profiling of potato (Solanum tuberosum, cv. Désirée) under heat, drought, and waterlogging applied as single stresses or in combinations designed to mimic realistic future scenarios. Stress responses were monitored via daily phenotyping and multi-omics analyses of leaf samples comprising proteomics, targeted transcriptomics, metabolomics, and hormonomics at several timepoints during and after stress treatments. Additionally, critical metabolites of tuber samples were analyzed at the end of the stress period. We performed integrative multi-omics data analysis using a bioinformatic pipeline that we established based on machine learning and knowledge networks. Waterlogging produced the most immediate and dramatic effects on potato plants, interestingly activating ABA responses similar to drought stress. In addition, we observed distinct stress signatures at multiple molecular levels in response to heat or drought and to a combination of both. In response to all treatments, we found a downregulation of photosynthesis at different molecular levels, an accumulation of minor amino acids, and diverse stress-induced hormones. Our integrative multi-omics analysis provides global insights into plant stress responses, facilitating improved breeding strategies toward climate-adapted potato varieties.

Elevated CO₂ concentration in the air (e[CO₂]) decreases stomatal density (SD) and stomatal conductance (g_s) where abscisic acid (ABA) may play a role, yet the underlying mechanism remains largely elusive. We investigated the effects of e[CO₂] (800 ppm) on leaf gas exchange and water relations of two tomato (Solanum lycopersicum) genotypes, Ailsa Craig (WT) and its ABA-deficient mutant (flacca). Compared to plants grown at ambient CO₂ (400 ppm), e[CO₂] stimulated photosynthetic rate in both genotypes, while depressed the g_s only in WT. SD showed a similar response to e[CO₂] as g_s, although the change was not significant. e[CO₂] increased leaf and xylem ABA concentrations and xylem sap pH, where the increases were larger in WT than in flacca. Although leaf water potential was unaffected by CO₂ growth environment, e[CO₂] lowered osmotic potential, hence tended to increase turgor pressure particularly for WT. e[CO₂] reduced hydraulic conductance of leaf and root in WT but not in flacca, which was associated with downregulation of gene expression of aquaporins. It is concluded that ABA-mediated regulation of g_s, SD, and gene expression of aquaporins coordinates the whole-plant hydraulics of tomato grown at different CO₂ environments.

Anthropogenic activities over the last century have caused rapid changes in environmental conditions through increasing CO₂ emissions in the atmosphere that contribute to global warming. Moreover, the increased global average temperature is linked with changes in the precipitation rate and distribution, resulting in a negative impact on crop health and productivity. Plants in nature often experience combined stresses; therefore, they have developed adaptive mechanisms to cope with fluctuating environmental conditions. Thus, investigating plant responses under unfavorable environmental conditions will provide a better understanding of how crops can adapt and thereby assist in selecting climate-resilient crops that can withstand climate variability. This review highlights the main adaptive physiological and biochemical responses of crops grown under elevated CO₂ (eCO₂) and exposed to combined abiotic stresses (drought and heat). Moreover, the mitigation and limitation impact of elevated CO₂ on plants under the combination of stress is discussed.

As drought and heat stress are major challenges for crop productivity under future climate changes, tolerant cultivars are highly in demand. This study investigated the potential of existing Nordic wheat genotypes to resist unfavorable conditions. Four genotypes were selected based on their heat sensitivity (heat-sensitive: LM19, SF1; heat-tolerant: LM62, NS3). At the tillering stage, the plants were subjected to four treatments under controlled conditions: control, drought, heat and combined drought and heat stress. The morpho-physiological performance was quantified during the early and late phase of stress, as well as the recovery phase. We applied an integrative image-based phenotyping approach monitoring plant growth dynamics by structural Red Green Blue (RGB) imaging, photosynthetic performance by chlorophyll fluorescence imaging and transpiration efficiency by thermal infrared imaging. The results demonstrated that the selected genotypes were moderately affected in their photosynthetic efficiency and growth under drought stress, whereas heat and combined stress caused rapid reductions in photosynthesis and growth. Furthermore, drought stress had a major impact on canopy temperature. The NS3 genotype was the most robust genotype, as indicated by its improved response under all stress treatments due to its relatively small biomass. However, the genotypes showed different tolerance to individual and combined stress.