Summary
Reactive oxygen species (ROS) play a key role in the acclimation process of plants to abiotic stress. They primarily function as signal transduction molecules that regulate different pathways ...during plant acclimation to stress, but are also toxic byproducts of stress metabolism. Because each subcellular compartment in plants contains its own set of ROS‐producing and ROS‐scavenging pathways, the steady‐state level of ROS, as well as the redox state of each compartment, is different at any given time giving rise to a distinct signature of ROS levels at the different compartments of the cell. Here we review recent studies on the role of ROS in abiotic stress in plants, and propose that different abiotic stresses, such as drought, heat, salinity and high light, result in different ROS signatures that determine the specificity of the acclimation response and help tailor it to the exact stress the plant encounters. We further address the role of ROS in the acclimation of plants to stress combination as well as the role of ROS in mediating rapid systemic signaling during abiotic stress. We conclude that as long as cells maintain high enough energy reserves to detoxify ROS, ROS is beneficial to plants during abiotic stress enabling them to adjust their metabolism and mount a proper acclimation response.
Significance Statement
Reactive oxygen species (ROS) primarily function as signal transduction molecules that regulate different pathways during acclimation to stress, but are also toxic byproducts of stress metabolism. Different subcellular compartments contain different sets of ROS‐producing and ROS‐scavenging pathways, and thus ROS levels can have different signatures in different cellular compartments. Here we review recent work on ROS and abiotic stress, and propose that different stresses, such as drought, heat, salinity and high light, result in different ROS signatures that determine the specificity of the acclimation response to a particular stress.
SUMMARY
Global warming and climate change are driving an alarming increase in the frequency and intensity of different abiotic stresses, such as droughts, heat waves, cold snaps, and flooding, ...negatively affecting crop yields and causing food shortages. Climate change is also altering the composition and behavior of different insect and pathogen populations adding to yield losses worldwide. Additional constraints to agriculture are caused by the increasing amounts of human‐generated pollutants, as well as the negative impact of climate change on soil microbiomes. Although in the laboratory, we are trained to study the impact of individual stress conditions on plants, in the field many stresses, pollutants, and pests could simultaneously or sequentially affect plants, causing conditions of stress combination. Because climate change is expected to increase the frequency and intensity of such stress combination events (e.g., heat waves combined with drought, flooding, or other abiotic stresses, pollutants, and/or pathogens), a concentrated effort is needed to study how stress combination is affecting crops. This need is particularly critical, as many studies have shown that the response of plants to stress combination is unique and cannot be predicted from simply studying each of the different stresses that are part of the stress combination. Strategies to enhance crop tolerance to a particular stress may therefore fail to enhance tolerance to this specific stress, when combined with other factors. Here we review recent studies of stress combinations in different plants and propose new approaches and avenues for the development of stress combination‐ and climate change‐resilient crops.
Significance Statement
Climate change and global warming increase the likelihood that trees and crop plants will be subjected to a combination of different abiotic and biotic stresses, compromising global food production and security. This paper reviews recent advances in the study of plant responses to stress combinations and proposes potential strategies to develop crops with high resilience to a wide range of stress factors and their combination.
Abiotic and biotic stress combinations Suzuki, Nobuhiro; Rivero, Rosa M.; Shulaev, Vladimir ...
The New phytologist,
July 2014, Letnik:
203, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Environmental stress conditions such as drought, heat, salinity, cold, or pathogen infection can have a devastating impact on plant growth and yield under field conditions. Nevertheless, the effects ...of these stresses on plants are typically being studied under controlled growth conditions in the laboratory. The field environment is very different from the controlled conditions used in laboratory studies, and often involves the simultaneous exposure of plants to more than one abiotic and/or biotic stress condition, such as a combination of drought and heat, drought and cold, salinity and heat, or any of the major abiotic stresses combined with pathogen infection. Recent studies have revealed that the response of plants to combinations of two or more stress conditions is unique and cannot be directly extrapolated from the response of plants to each of the different stresses applied individually. Moreover, the simultaneous occurrence of different stresses results in a high degree of complexity in plant responses, as the responses to the combined stresses are largely controlled by different, and sometimes opposing, signaling pathways that may interact and inhibit each other. In this review, we will provide an update on recent studies focusing on the response of plants to a combination of different stresses. In particular, we will address how different stress responses are integrated and how they impact plant growth and physiological traits.
Abiotic stresses such as drought, heat or salinity are a major cause of yield loss worldwide. Recent studies revealed that the acclimation of plants to a combination of different environmental ...stresses is unique and cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. Here we report on the response of Arabidopsis thaliana to a combination of salt and heat stress using transcriptome analysis, physiological measurements and mutants deficient in abscisic acid, salicylic acid, jasmonic acid or ethylene signaling. Arabidopsis plants were found to be more susceptible to a combination of salt and heat stress compared to each of the different stresses applied individually. The stress combination resulted in a higher ratio of Na+/K+ in leaves and caused the enhanced expression of 699 transcripts unique to the stress combination. Interestingly, many of the transcripts that specifically accumulated in plants in response to the salt and heat stress combination were associated with the plant hormone abscisic acid. In accordance with this finding, mutants deficient in abscisic acid metabolism and signaling were found to be more susceptible to a combination of salt and heat stress than wild type plants. Our study highlights the important role abscisic acid plays in the acclimation of plants to a combination of two different abiotic stresses.
Abiotic stresses such as drought, heat or salinity are major causes of yield loss worldwide. Recent studies have revealed that the acclimation of plants to a combination of different environmental ...stresses is unique and therefore cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. The efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Here, we report on the role of melatonin in the protection of the photosynthetic apparatus through the increase in ROS detoxification in tomato plants grown under the combination of salinity and heat, two of the most common abiotic stresses known to act jointly. Plants treated with exogenous melatonin showed a different modulation in the expression on some antioxidant-related genes and their related enzymes. More specifically, ascorbate peroxidase, glutathione reductase, glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase (APX, GR, GPX and Ph-GPX, resepctively) showed an antagonistic regulation as compared to plants that did not receive melatonin. This translated into a better antioxidant capacity and to a lesser ROS accumulation under stress combination. The performance of the photosynthesis parameters and the photosystems was also increased in plants treated with exogenous melatonin under the combination of salinity and heat. In accordance with these findings, tomato plants treated with melatonin were found to grow better under stress combination that the non-treated ones. Our study highlights the important role that exogenous melatonin plays in the acclimation of plants to a combination of two different abiotic stresses, and how this compound can specifically regulate oxidative stress-related genes and enzymes to increase plant tolerance.
Many studies have described the response mechanisms of plants to salinity and heat applied individually; however, under field conditions some abiotic stresses often occur simultaneously. Recent ...studies revealed that the response of plants to a combination of two different stresses is specific and cannot be deduced from the stresses applied individually. Here, we report on the response of tomato plants to a combination of heat and salt stress. Interestingly, and in contrast to the expected negative effect of the stress combination on plant growth, our results show that the combination of heat and salinity provides a significant level of protection to tomato plants from the effects of salinity. We observed a specific response of plants to the stress combination that included accumulation of glycine betaine and trehalose. The accumulation of these compounds under the stress combination was linked to the maintenance of a high K⁺ concentration and thus a lower Na⁺/K⁺ ratio, with a better performance of the cell water status and photosynthesis as compared with salinity alone. Our findings unravel new and unexpected aspects of the response of plants to stress combination and provide a proposed list of enzymatic targets for improving crop tolerance to the abiotic field environment.
Wine pomace (WP) is one of the agricultural byproducts that has received most attention from food scientists due to the wide range of interesting compounds that remain after the winemaking process. ...Different powdered products rich in phenolic compounds, with interesting antioxidant and antimicrobial activities, were obtained from WP by applying processes that are both environmentally friendly and economically affordable for the food industry. The products obtained showed high global antioxidant activities (ABTS assay), successfully delayed the onset of lipid oxidation in the Rancimat test, and showed different antimicrobial properties. Products derived from seed-free WP showed bactericidal effects against total aerobic mesophilic bacteria (TAMB) and lactic acid bacteria (LAB) and inhibited Enterobacteriaceae growth completely. The product derived from whole WP presented bacteriostatic activity against the three microorganism groups tested, whereas the product obtained from grape seed promoted TAMB and LAB growth but delayed Enterobacteriaceae proliferation.
Grazing plays an important role in milk production in most regions of the world. In this review, some challenges to the grazing cow are discussed together with opportunities for future improvement. ...We focus on daily feed intake, efficiency of pasture utilization, output of milk per head, environmental impact of grazing and the nutritional quality to humans of milk produced from dairy cows in contrasting production systems. Challenges are discussed in the context of a trend towards increased size of individual herds and include limited and variable levels of daily herbage consumption, lower levels of milk output per cow, excessive excretion of nitrogenous compounds and requirements for minimal periods of grazing regardless of production system. A major challenge is to engage more farmers in making appropriate adjustments to their grazing management. In relation to product quality, the main challenge is to demonstrate enhanced nutritional/processing benefits of milk from grazed cows. Opportunities include more accurate diet formulations, supplementation of grazed pasture to match macro‐ and micronutrient supply with animal requirement and plant breeding. The application of robotics and artificial intelligence to pasture management will assist in matching daily supply to animal requirement. Wider consumer recognition of the perceived enhanced nutritional value of milk from grazed cows, together with greater appreciation of the animal health, welfare and behavioural benefits of grazing should contribute to the future sustainability of demand for milk from dairy cows on pasture.
Understanding the behaviour of grazing animals at pasture is crucial in order to develop management strategies that will increase the potential productivity of grazing systems and simultaneously ...decrease the negative impact on the environment. The objective of this review was to summarize and analyse the scientific literature that has addressed the site use preference of grazing cattle using global positioning systems (GPS) collars in the past 21 years (2000-2020) to aid the development of more sustainable grazing livestock systems. The 84 studies identified were undertaken in several regions of the world, in diverse production systems, under different climate conditions and with varied methodologies and animal types. This work presents the information in categories according to the main findings reviewed, covering management, external and animal factors driving animal movement patterns. The results showed that some variables, such as stocking rate, water and shade location, weather conditions and pasture (terrain and vegetation) characteristics, have a significant impact on the behaviour of grazing cattle. Other types of bio-loggers can be deployed in grazing ruminants to gain insights into their metabolism and its relationship with the landscape they utilise. Changing management practices based on these findings could improve the use of grasslands towards more sustainable and productive livestock systems.
We investigated the effects of PSARK::IPT (for Senescence-Associated Receptor Kinase::Isopentenyltransferase) expression and cytokinin production on several aspects of photosynthesis in transgenic ...tobacco (Nicotiana tabacum cv SR1) plants grown under optimal or restricted (30% of optimal) watering regimes. There were no significant differences in stomatal conductance between leaves from wild-type and transgenic PSARK-IPT plants grown under optimal or restricted watering. On the other hand, there was a significant reduction in the maximum rate of electron transport as well as the use of triose-phosphates only in wild-type plants during growth under restricted watering, indicating a biochemical control of photosynthesis during growth under water deficit. During water deficit conditions, the transgenic plants displayed an increase in catalase inside peroxisomes, maintained a physical association among chloroplasts, peroxisomes, and mitochondria, and increased the CO₂ compensation point, indicating the cytokinin-mediated occurrence of photorespiration in the transgenic plants. The contribution of photorespiration to the tolerance of transgenic plants to water deficit was also supported by the increase in transcripts coding for enzymes involved in the conversion of glycolate to ribulose-1,5-bisphosphate. Moreover, the increase in transcripts indicated a cytokinin-induced elevation in photorespiration, suggesting the contribution of photorespiration in the protection of photosynthetic processes and its beneficial role during water stress.
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