Adaptive Mechanisms of Halophytes and Their Potential in Improving Salinity Tolerance in Plants

Abstract

Soil salinization, which is aggravated by climate change and inappropriate anthropogenic activities, has emerged as a serious environmental problem, threatening sustainable agriculture and future food security. Although there has been considerable progress in developing crop varieties by introducing salt tolerance-associated traits, most crop cultivars grown in saline soils still exhibit a decline in yield, necessitating the search for alternatives. Halophytes, with their intrinsic salt tolerance characteristics, are known to have great potential in rehabilitating salt-contaminated soils to support plant growth in saline soils by employing various strategies, including phytoremediation. In addition, the recent identification and characterization of salt tolerance-related genes encoding signaling components from halophytes, which are naturally grown under high salinity, have paved the way for the development of transgenic crops with improved salt tolerance. In this review, we aim to provide a comprehensive update on salinity-induced negative effects on soils and plants, including alterations of physicochemical properties in soils, and changes in physiological and biochemical processes and ion disparities in plants. We also review the physiological and biochemical adaptation strategies that help halophytes grow and survive in salinity-affected areas. Furthermore, we illustrate the halophyte-mediated phytoremediation process in salinity-affected areas, as well as their potential impacts on soil properties. Importantly, based on the recent findings on salt tolerance mechanisms in halophytes, we also comprehensively discuss the potential of improving salt tolerance in crop plants by introducing candidate genes related to antiporters, ion transporters, antioxidants, and defense proteins from halophytes for conserving sustainable agriculture in salinity-prone areas.

Ethanol Treatment Enhances Physiological and Biochemical Responses to Mitigate Saline Toxicity in Soybean

“…Climate change-induced extreme environmental conditions, such as salinity, drought, temperature extremes, and waterlogging, pose serious challenges to global agriculture, threatening food security [ 1 ]. Furthermore, given the current water-scarce scenario, high saline water is increasingly being used to meet the growing need for water for agricultural production in many parts of the world [ 2 , 3 ]. Consequently, an increasing level of soil salinity has emerged as a paramount environmental problem, affecting around 3.6 billion hectares (Bha) out of 5.22 Bha of the world’s agricultural land, with an annual loss of USD 27.5 billion [ 2 , 4 , 5 ].…”

“…Furthermore, given the current water-scarce scenario, high saline water is increasingly being used to meet the growing need for water for agricultural production in many parts of the world [ 2 , 3 ]. Consequently, an increasing level of soil salinity has emerged as a paramount environmental problem, affecting around 3.6 billion hectares (Bha) out of 5.22 Bha of the world’s agricultural land, with an annual loss of USD 27.5 billion [ 2 , 4 , 5 ]. Plants grown in salt-contaminated soils have accumulated excessive toxic ions, resulting in a variety of morphological, physiological, and biochemical disturbances, such as ionic disparities, poor gas exchange performance, photosynthetic pigments loss, low water status, and excessive reactive oxygen species (ROS)-induced oxidative damage to cellular components [ 2 , 6 , 7 , 8 , 9 ].…”

“…Consequently, an increasing level of soil salinity has emerged as a paramount environmental problem, affecting around 3.6 billion hectares (Bha) out of 5.22 Bha of the world’s agricultural land, with an annual loss of USD 27.5 billion [ 2 , 4 , 5 ]. Plants grown in salt-contaminated soils have accumulated excessive toxic ions, resulting in a variety of morphological, physiological, and biochemical disturbances, such as ionic disparities, poor gas exchange performance, photosynthetic pigments loss, low water status, and excessive reactive oxygen species (ROS)-induced oxidative damage to cellular components [ 2 , 6 , 7 , 8 , 9 ]. Plants, on the other hand, employ a wide array of mechanisms to counteract the detrimental consequences of salt stress.…”

“…Plants, on the other hand, employ a wide array of mechanisms to counteract the detrimental consequences of salt stress. For example, salt-exposed plants mount mechanisms to (i) reduce toxic ion accumulations in the aerial parts; (ii) limit the destruction of photosynthetic pigments; (iii) increase the accumulation of osmoprotectants, such as proline (Pro), free amino acids and soluble sugars; and (iv) enhance the activities of antioxidant enzymes, including superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), glutathione S -transferase (GST), and glutathione peroxidase (GPX), and the contents of nonenzymatic compounds, such as carotenoids, phenolic compounds, and flavonoids [ 2 , 7 , 8 ].…”

Melatonin increases growth and salt tolerance of Limonium bicolor by improving photosynthetic and antioxidant capacity

“…Among these stressors, soil salinization is becoming an increasingly serious problem worldwide, causing cultivated land loss and desertification and seriously impacting agriculture and the economy [ 10 , 17 , 18 , 36 ]. Some plants such as halophytes with high salt tolerance can survive in saline soils being higher or equal to 200 mM NaCl, which can increase the use of saline land and even improve it [ 7 , 11 , 31 , 32 , 41 ]. Salt stress causes not only osmotic and ionic stresses, but also oxidative stress, which inhibits photosynthesis, nutrient use, protein synthesis, and enzyme activity [ 8 , 17 , 18 , 37 ].…”