Trehalose alleviates salt tolerance by improving photosynthetic performance and maintaining mineral ion homeostasis in tomato plants

Abstract

Trehalose (Tre), which was an osmoprotective or stabilizing molecule, played a protective role against different abiotic stresses in plants and showed remarkable perspectives in salt stress. In this study, the potential role of Tre in improving the resistance to salt stress in tomato plants was investigated. Tomato plants (Micro Tom) were treated with Hoagland nutrient solution (CK), 10 mM Tre (T), 150 mM sodium chloride (NaCl, S), and 10 mM Tre+150 mM NaCl (S+T) for 5 days. Our results showed that foliar application of Tre alleviated the inhibition of tomato plant growth under salt stress. In addition, salt stress decreased the values of net photosynthetic rate (Pn, 85.99%), stomata conductance (gs, 57.3%), and transpiration rate (Tr, 47.97%), but increased that of intercellular carbon dioxide concentration (Ci, 26.25%). However, exogenous application of Tre significantly increased photosynthetic efficiency, increased the activity of Calvin cycle enzymes [ribulose diphosphate carboxylase/oxygenase (Rubisco), fructose-1,6-bisphosphate aldolase (FBA), fructose-1, 6-bisphosphatase (FBPase), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and transketolase (TK)], up-regulated the expression of genes encoding enzymes, induced stomatal opening, and alleviated salt-induced damage to the chloroplast membrane and structure. In the saline environment, photosynthetic electron transport was restricted, resulting the J-I-P phase to decrease. At the same time, the absorption, capture, and transport energies per excited cross-section and per active reaction center decreased, and the dissipation energy increased. Conversely, Tre reversed these values and enhanced the photosystem response to salt stress by protecting the photosynthetic electron transport system. In addition, foliage application with Tre significantly increased the potassium to sodium transport selectivity ratio (SK–Na) by 16.08%, and increased the levels of other ions to varying degrees. Principal component analysis (PCA) analysis showed that exogenous Tre could change the distribution of elements in different organs and affect the expressions of SlSOS1, SlNHX, SlHKT1.1, SlVHA, and SlHA-A at the transcriptional level under salt stress, thereby maintaining ion homeostasis. This study demonstrated that Tre was involved in the process of mitigating salt stress toxicity in tomato plants and provided specific insights into the effectiveness of Tre in mediating salt tolerance.

Effects of Exogenous Glycine Betaine and Cycloleucine on Photosynthetic Capacity, Amino Acid Composition, and Hormone Metabolism in Solanum melongena L

“…Key enzymes of the Calvin cycle (RuBisCO, GAPDH, FBA, FBPase, and TK) play an irreplaceable role in photosynthesis 44,45 . RuBisCO and FBPase play important roles in carbon xation: reduction and RuBP regeneration, respectively.…”

“…The second leaf of ve plants was selected for a replicate of each treatment. The conditions set during measurement were as follows: leaf area, 1.7 cm 2 ; chamber ow rate, 200 mL min − 1 ; photosynthetically active irradiation, 1000 µmol m − 2 s − 1 ; carbon dioxide (CO 2 ) concentration, 400 µmol mol − 1 ; air temperature, 25℃; and relative humidity, 75% 44 .…”

“…When plants were grown for 60 days, the middle part of their leaves was cut off in 5×5 mm pieces with a scalpel and immersed in 2.5% glutaraldehyde xative for electron microscopy (Shanghai Yuanye Bio-Technology Co., Ltd., Shanghai, China). The dehydration method described by Yang, et al 44 was used.…”

The transcriptional regulatory network of hormones and genes under salt stress in tomato plants (Solanum lycopersicum L.)

“…Cultivated tomatoes had gradually lost their capacity to adapt to high salt stress during the domestication process ( Sato et al., 2012 ). At present, preliminary studies on mechanisms of salt tolerance in tomato had been reported ( Yang et al., 2022 ), but the hormone-related regulatory network of tomato plants under salt stress remained unclear. Further studies on the regulatory networks of hormone metabolism and signal transduction might be important to precisely elucidate the salt stress mechanism of tomato plants.…”

The Role of Trehalose-producing Bradyrhizobium japonicum and Azotobacter chroococcum in Enhancing Salinity Tolerance of Zea mays Plants

“…This crop is extremely vulnerable to abiotic stress brought on by drought, excessive salinity, and extreme temperatures, which can result in yield reductions of up to 15% and an estimated loss of 16 million tonnes of grain [24]. It is therefore necessary to put strategies in place to reduce these losses as [25] who proved that the exogenously application of soaking rice seeds with 25 mM of trehalose could alleviate the harmful effects of salinity stress [26] proved that foliar application of trehalose had significant and positive effect on most growth parameters of wheat plants [27] confirmed that trehalose can efectively alleviate salt stress and enhance salt tolerance of tomato [28] concluded that trehalose treatments (100 µM or 500 µM) had pronounce effect in alleviating the harmful effect of moderate and severe drought stress on cowpea plant and enhanced its drought tolerance [29] demonstrated that trehalose was involved in the process of mitigating salt stress toxicity in tomato plants and provided specific insights into the effectiveness of trehalose in mediating salt tolerance.…”