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Drought stress is one of the main environmental factors that limit plant growth and productivity. In order to endure such stress, which increases every year, plants developed different strategies to withstand drought conditions, including an enzymatic antioxidant defense system with enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), and glutathione-S-transferase (GST), among others, playing key roles. Therefore, efforts to develop new drought-tolerant varieties have become essential for maintaining human populations increasing researchers' interest in tools and/or mechanisms involved in drought tolerance. Thus, this work is aimed at offering a systematic review of the correlation between gene expression and antioxidant enzyme activity in water-stress tolerant plants for fourteen most important food crops worldwide, according to FAO, and Arabidopsis thaliana. This systematic review was performed using the free software StArt and the PICOS strategy. Among the factors that generate drought tolerance is the increased activity/gene expression of antioxidant enzymes. The use of plant regulators stood out as the most critical substance among chemical inputs; however, these do not provide long-term tolerance and therefore, the development of genetically modified organisms would be the most efficient technique for promoting tolerance to long-term water deficit in plants. In this systematic review, data was collected, and forty candidate genes were identified as responsible for water deficit tolerance, which can be used by plant breeding programs to develop genetically engineered products. [ABSTRACT FROM AUTHOR]

Rosa damascena is one of the oldest valuable rose flower varieties that is almost drough tolerant. However, selecting and identifying landraces that are more tolerant to drought conditions will be effective in developing the cultivation of the plant under stress. The most important step in developing drought-tolerant plants is the evaluation and identification of resistant and susceptible genotypes. In this case, an experiment was performed under in vitro conditions using five levels (0, 25, 50, 75, and 100 g/L) of polyethylene glycol (PEG) on four landraces of the Damask rose (Maragheh, Urmia, Pakdasht, and Kashan). Based on the findings, the resistance of the different landraces to a water deficit was measured by the Design-Expert software using the response level (RSM) method. The results showed that Maragheh, with the highest fresh and dry weight, total chlorophyll, chlorophyll a, chlorophyll b, proline and an increase in the superoxide dismutase activity, had a high tolerance to drought stress. Moreover, Maragheh with a decreasing leaf number, height, malondialdehyde, hydrogen peroxide and having a higher membrane stability index, showed a better defence mechanism against oxidative stress than the other landraces. Also, after Maragheh, Pakdasht had the best performance compared to the other two landraces up to 75g/L of PEG, but not as well as Maragheh at the highest level of the tested PEG. Urmia and especially Kashan probably do not have much tolerance to drought stress regarding all the results and levels of desirability.

Climate change alters regular weather seasonality. Corn is one of the main crops affected by irregular water regimes. Due to complications in decision-making processes related to climate change, it is estimated that planting corn outside the optimal window results in around USD 340 million in losses per year in the United States' Corn Belt. In turn, exogenous plant growth regulators have been gaining prominence due to their potential to positively influence the morphology and physiology of plants under stress. This study was based on the hypothesis that the use of plant growth regulators can assist in mitigating the adverse effects of climate change on corn plants sown both inside and outside the recommended planting period. In this context, the effects of biostimulant application on gas exchange in corn plants sown within and outside the recommended period were evaluated. The experiment was carried out in randomized blocks in a 4 × 5 × 2 factorial scheme with four repetitions. These were four sowing times, the application of the biostimulants via seeds in five doses, and foliar applications (presence and absence). The biostimulant doses were 0.00, 6.25, 12.50, 18.75, and 25 mL kg−1. The foliar application used a dose of 500 mL ha−1. Only in the period (2017/2) higher doses of biostimulants indicated a decrease in the water use efficiency of plants, suggesting the need to evaluate this variable carefully. In this regard, future studies may investigate the ideal doses and application timings of biostimulants for different edaphoclimatic conditions. In general, the combined use of biostimulants on seeds and as a foliar treatment boosted physiological activity and stimulated photosynthetic processes in corn plants. Based on these data, plant regulators can be a useful tool to mitigate the adverse effects of climate change on corn plants sown inside and outside the planting period. [ABSTRACT FROM AUTHOR]

Water deficit during grain filling is a key factor on soybean (Glycine max (L.) Merrill) production, but plant response to different water stress levels should be better understood. This study evaluated soybean plant response to different soil water levels during grain filling. It was assessed the gravimetrical humidity and soil matric potential, leaf relative water content, leaf water potential, proline, and yield components of plants under a range of days without irrigation (0, 3, 6, 9, and 12) during grain filling phase. Until soil matric potential was around −0.8 atm soybean water deficit tolerance mechanisms were enough to maintain leaf relative water content and leaf water potential at acceptable levels, which proline concentration was a key factor in this mechanism. Leaf relative water content and leaf water potential showed to be related in maintaining soybean yield under water deficit and they may be used in studies of soybean tolerant cultivars to water restriction. From 9 days on, critical yield losses were observed due to water stress. The information presented in this study supports soybean producers in decision-making in irrigated systems to minimize productivity losses due to water deficit during the critical period of the crop–grain filling. [ABSTRACT FROM AUTHOR]

Rosa damascena is one of the oldest valuable rose flower varieties that is almost drough tolerant. However, selecting and identifying landraces that are more tolerant to drought conditions will be effective in developing the cultivation of the plant under stress. The most important step in developing drought-tolerant plants is the evaluation and identification of resistant and susceptible genotypes. In this case, an experiment was performed under in vitro conditions using five levels (0, 25, 50, 75, and 100 g/L) of polyethylene glycol (PEG) on four landraces of the Damask rose (Maragheh, Urmia, Pakdasht, and Kashan). Based on the findings, the resistance of the different landraces to a water deficit was measured by the Design-Expert software using the response level (RSM) method. The results showed that Maragheh, with the highest fresh and dry weight, total chlorophyll, chlorophyll a, chlorophyll b, proline and an increase in the superoxide dismutase activity, had a high tolerance to drought stress. Moreover, Maragheh with a decreasing leaf number, height, malondialdehyde, hydrogen peroxide and having a higher membrane stability index, showed a better defence mechanism against oxidative stress than the other landraces. Also, after Maragheh, Pakdasht had the best performance compared to the other two landraces up to 75g/L of PEG, but not as well as Maragheh at the highest level of the tested PEG. Urmia and especially Kashan probably do not have much tolerance to drought stress regarding all the results and levels of desirability. [ABSTRACT FROM AUTHOR]

Water deficit negatively impacts crop productivity and quality. Plants face these challenges by adjusting biological processes and molecular functions according to the intensity and duration of the stress. The cultivated potato (Solanum tuberosum) is considered sensitive to water deficit, thus breeding efforts are needed to enhance its resilience. To capture novel functional information and gene regulatory networks, we carried out mass spectrometry-based proteomics in potato cell suspensions exposed to abrupt or stepwise osmotic stresses. Both forms of stress triggered significant alterations in protein expression, though with divergent response mechanisms. Stress response pathways orchestrated by key proteins enrolled in primary and secondary metabolism, antioxidant processes, transcriptional and translational machinery and chromatin organization were found in adapted cells. Target metabolites and reactive oxygen species levels were quantified to associate functional outcomes with the proteome study. Remarkably, we also showed that adapted cells tolerate an array of diverse conditions, including anoxia, salt and heat stress. Finally, the expression patterns of genes encoding selected differentially expressed proteins were investigated in potato plants subjected to either drought or salt stress. Collectively, our findings reveal the complex cellular strategies of osmotic stress adaptation, identifying new fundamental genes that could enhance potato resilience., (© 2024 The Author(s). Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Climate change alters regular weather seasonality. Corn is one of the main crops affected by irregular water regimes. Due to complications in decision-making processes related to climate change, it is estimated that planting corn outside the optimal window results in around USD 340 million in losses per year in the United States’ Corn Belt. In turn, exogenous plant growth regulators have been gaining prominence due to their potential to positively influence the morphology and physiology of plants under stress. This study was based on the hypothesis that the use of plant growth regulators can assist in mitigating the adverse effects of climate change on corn plants sown both inside and outside the recommended planting period. In this context, the effects of biostimulant application on gas exchange in corn plants sown within and outside the recommended period were evaluated. The experiment was carried out in randomized blocks in a 4 × 5 × 2 factorial scheme with four repetitions. These were four sowing times, the application of the biostimulants via seeds in five doses, and foliar applications (presence and absence). The biostimulant doses were 0.00, 6.25, 12.50, 18.75, and 25 mL kg−1. The foliar application used a dose of 500 mL ha−1. Only in the period (2017/2) higher doses of biostimulants indicated a decrease in the water use efficiency of plants, suggesting the need to evaluate this variable carefully. In this regard, future studies may investigate the ideal doses and application timings of biostimulants for different edaphoclimatic conditions. In general, the combined use of biostimulants on seeds and as a foliar treatment boosted physiological activity and stimulated photosynthetic processes in corn plants. Based on these data, plant regulators can be a useful tool to mitigate the adverse effects of climate change on corn plants sown inside and outside the planting period.

Limited soil water availability is a major threat to agricultural productivity because it inhibits plant growth and yields. Soil microorganisms having the ability to alleviate abiotic stress and promoting plant development would be highly valuable tools in sustainable agriculture. To this purpose, two Rhizobium leguminosarum strains were tested for their potential to induce tolerance against water deficits in Triticum durum grown under two hydric conditions in greenhouse experiments. For this, physiological and biochemical parameters were measured as criteria to assess the effect of R. leguminosarum inoculation on T. durum under water deficiency. In the presence of rhizobia, wheat plants were able to withstand water stress more effectively than un-inoculated plant, as indicated by the recorded increases in relative water content of inoculated plants compared to un-inoculated plants, higher accumulation of osmoprotectant (soluble sugar), lower MDA and H2O2 accumulation, and increased in antioxidant responses (peroxidase). Under water-limited condition, co-inoculation of selected rhizobia was better than single application for one of studied genotype, which let us hypothesize that this variation in responsiveness indicates a possible genotype effect. As a result, rhizobia from various legumes have a huge potential for enhancing the water deficiency stress tolerance of cereals. [ABSTRACT FROM AUTHOR]