Mechanism of salt tolerance ability of novel Desertifilum salkalinema SSAU 7 for sustainable development.

Soil salinity is one of the major global issues affecting soil quality and agricultural productivity. The plant growth-promoting halophilic bacteria that can thrive in regions of high salt (NaCl) concentration have the ability to promote the growth of plants in salty environments. In this study, attempts have been made to understand the salinity adaptation of plant growth-promoting moderately halophilic bacteria Chromohalobacter salexigens ANJ207 at the genetic level through transcriptome analysis. In order to identify the stress-responsive genes, the transcriptome sequencing of C. salexigens ANJ207 under different salt concentrations was carried out. Among the 8,936 transcripts obtained, 93 were upregulated while 1,149 were downregulated when the NaCl concentration was increased from 5 to 10%. At 10% NaCl concentration, genes coding for lactate dehydrogenase, catalase, and OsmC-like protein were upregulated. On the other hand, when salinity was increased from 10 to 25%, 1,954 genes were upregulated, while 1,287 were downregulated. At 25% NaCl, genes coding for PNPase, potassium transporter, aconitase, excinuclease subunit ABC, and transposase were found to be upregulated. The quantitative real-time PCR analysis showed an increase in the transcript of genes related to the biosynthesis of glycine betaine coline genes (gbcA, gbcB, and L-pro) and in the transcript of genes related to the uptake of glycine betaine (OpuAC, OpuAA, and OpuAB). The transcription of the genes involved in the biosynthesis of L-hydroxyproline (proD and proS) and one stress response proteolysis gene for periplasmic membrane stress sensing (serP) were also found to be increased. The presence of genes for various compatible solutes and their increase in expression at the high salt concentration indicated that a coordinated contribution by various compatible solutes might be responsible for salinity adaptation in ANJ207. The investigation provides new insights into the functional roles of various genes involved in salt stress tolerance and oxidative stress tolerance produced by high salt concentration in ANJ207 and further support the notion regarding the utilization of bacterium and their gene(s) in ameliorating salinity problem in agriculture.

Background: Salt stress is a significant environmental factor that affects plant growth and productivity, particularly in regions with increasing soil salinization. Understanding the impact of different salt types and concentrations on seed germination and seedling vigor is crucial for developing strategies to mitigate salinity stress in agricultural settings. This study evaluates the effects of NaCl and KCl at varying concentrations on the germination and seedling vigor of the Goksu chickpea cultivar (Cicer arietinum L.). Methods: The study was conducted at Gaziantep University, Nurdagi Vocational School between November 2022 and January 2023. This study evaluates the effects of different salt types (NaCl and KCl) and their varying concentrations on the germination and seedling vigor of the Goksu chickpea cultivar. The experiment was conducted under controlled conditions with seven different concentrations of each salt (0, 25, 50, 75, 100, 125 and 150 mm). Result: It is indicated that increasing salt concentrations had a negative impact on all measured parameters. GP decreased significantly with higher salt levels, with NaCl treatments generally exhibiting higher GP compared to KCl. The MGT increased with higher salt concentrations, reflecting the delayed germination process under salinity stress. Both radicle and PL were adversely affected, with NaCl having a more pronounced negative impact compared to KCl. The GI, CVG and SVI also decreased significantly with higher salt concentrations, demonstrating the overall decline in seedling vigor under salinity stress.

Dryland field validation of genotypic variation in salt tolerance of chickpea (Cicer arietinum L.) determined under controlled conditions

Chlorophyll fluorescence (CF) parameters, plant growth, and chlorophyll and proline content were investigated in the seedlings of four tomato (Solanum lycopersicum L.) cultivars (‘Dafnis’, ‘Maxifort’, ‘BKO’, and ‘B-blocking’) exposed to 0, 50, 100, 150, 200, 300, and 400 mM NaCl concentrations for 15 days. The maximum quantum yield (Fv/Fm) showed progressively decreased at 300 and 400 mM salt concentrations in all the cultivars, with the highest decrement in Dafnis. In contrast, the quantum yield of nonregulated energy dissipation in photosystem II (PSII) [Y(NO)] showed a reverse accumulation pattern at higher salt concentrations as the treatment time increased, regardless of the genotype. Other CF parameters, such as the coefficient of nonphotochemical quenching, excitation transfer efficiency from antenna pigments to the reaction center of PSII in the light-adapted state, effective quantum yield of photochemical energy conversion in PSII, nonphotochemical quenching, and the ratio of chlorophyll fluorescence decrease were lower at higher salt concentrations; however, some inconsistencies were observed at 5 and 10 days after the treatment time depending upon the cultivar and salt concentration. Growth parameters such as plant height, stem diameter, number of nodes, and shoot fresh and dry weight decreased by about 2.2–3.2, 1.1–1.6, 1.7–2.0, 3.1–6.8, and 1.8–3.2 times, respectively, in the salt-stressed cultivars. In the seedlings, the proline content significantly increased, with the highest increment observed in the seedlings treated with 100–200 mM salt concentration. Both chlorophyll a and b decreased as the salt concentration increased. Among the four cultivars, Dafnis showed the highest response to the salt concentrations with respect to all the parameters. In conclusion, our results suggest that the CF parameters Fv/Fm and Y(NO) can be used as indices for screening tomato genotypes with salt tolerance.

A greenhouse experiment was conducted on four crop plants in the western region of Gujarat State, India to assess their responses to increasing levels of soil salinity. Of the four crop plants tested (Hordeum vulgare, barley; Triticum aestivum, wheat; Cicer arietinum, gram and Brassica juncea, mustard), barley appeared to be the most tolerant to salinity with regard to seed germination and early growth of the plants. Wheat, gram and mustard were tolerant only to low soil salinity. However, high salt concentrations in the soil reduced the absorption of nitrogen and phosphorus by the young plants. The imbalance of mineral nutrients resulted in a reduction or an inhibition of plant growth. High salinity also caused burning symptoms on the leaves and shoot apices of barley.

The phase behavior of polyelectrolyte complexes and coacervates (PECs) at low salt concentrations has been well characterized, but their behavior at concentrations well above the binodal is not well understood. Here, we investigate the phase behavior of stoichiometric poly(styrene sulfonate)/poly(diallyldimethylammonium) mixtures at high salt and high polymer concentrations. Samples were prepared by direct mixing of PSS/PDADMA PECs, water, and salt (KBr). Phase separation was observed at salt concentrations approximately 1 M above the binodal. Characterization by thermogravimetric analysis, FTIR, and NMR revealed that both phases contained significant amounts of polymer, and that the polymer-rich phase was enriched in PSS, while the polymer-poor phase was enriched in PDADMA. These results suggest that high salt concentrations drive salting out of the more hydrophobic polyelectrolyte (PSS), consistent with behavior observed in weak polyelectrolyte systems. Interestingly, at the highest salt and polymer concentrations studied, the polymer-rich phase contained both PSS and PDADMA, suggesting that high salt concentrations can drive salting out of partially-neutralized complexes as well. Characterization of the behavior of PECs in the high concentration limit appears to be a fruitful avenue for deepening fundamental understanding of the molecular-scale factors driving phase separation in these systems.

Saffron stigmas are widely used as food additives and as traditional medicine in Iran and many other countries. The unique taste, flavor and pharmaceutical properties of saffron stigmas are due to the presence of three apocarotenoids secondary metabolites crocin, picrocrocin and safranal. There is limited knowledge about the effect of environmental stresses on the metabolism of apocarotenoids in saffron. We analyzed the content of crocin and picrocrocin and the expression of key genes of apocarotenoid biosynthesis pathways (CsCCD2, CsCCD4, CsUGT2, CsCHY-β and CsLCYB) in saffron plants exposed to moderate (90mM) and high (150mM) salt (NaCl)concentrations. Measuring ion concentrations in leaves showed an increased accumulation of Na+ and decreased uptake of K+ in salt treated compared to control plants indicating an effective salt stress. HPLC analysis of apocarotenoids revealed that crocin production was significantly halted (P < 0.05) with increasing salt concentration while picrocrocin level did not change with moderate salt but significantly dropped by high salt concentration. Real-time PCR analysis revealed a progressive decrease in transcript levels of CsUGT2 and CsLCYB genes with increasing salt concentration (P < 0.05). The expression of CsCCD2 and CsCHY-β tolerated moderate salt concentration but significantly downregulated with high salt concentration. CsCCD4 however responded differently to salt concentration being decreased with moderate salt but increased at higher salt concentration. Our result suggested that salt stress had an adverse effect on the production of saffron apocarotenoids and it is likely influencing the quality of saffron stigma produced.

The effects of 0.0, 0.01, 0.1, and 1.0 M concentrations of sodium, copper and calcium chloride salts added to a Pima clay loam with and without 15 NH 4 Cl on mineralization of soil nitrogen, nitrification, and immobilization were measured over a 49‐day period. Dilute concentrations of salt, 15 NH 4 Cl, and dilute salts plus 15 NH 4 Cl stimulated mineralization of soil N. The “priming effect” was shown to be real and not just a simple exchange. Nitrification of native ammonium nitrogen and 15 N‐labeled ammonium decreased with increasing concentrations of salt. High concentrations of copper and calcium chloride salts inhibited nitrification of 15 N‐labeled ammonium more than sodium salts. Immobilization of 15 NH 4 + ‐N was decreased significantly by high concentrations of salt. Gaseous loss processes were decreased with increased salts.

We investigated if salt tolerance can be inferred from observable cues based on a woody species’ native habitat and leaf traits. Such inferences could improve species selection for urban landscapes constrained by soils irrigated with reclaimed water. We studied the C3 tree species Acer grandidentatum Nutt. (canyon maple; xeric-non-saline habitat) that was hypothesized to have some degree of salt tolerance based on its semiarid but non-saline native habitat. We compared it with A. macrophyllum Pursh. (bigleaf maple) from mesic/riparian-non-saline habitats with much larger leaves and Eucalyptus camaldulensis Dehnh. (eucalyptus/red gum) from mesic-saline habitats with schlerophyllous evergreen leaves. Five levels of increasing salt concentrations (non-saline control to 12 dS·m−1) were applied over 5 weeks to container-grown seedling trees in two separate studies, one in summer and the other in fall. We monitored leaf damage, gas exchange, and hydric behavior as measures of tree performance for 3 weeks after target salinity levels were reached. Eucalyptus was the most salt-tolerant among the species. At all elevated salinity levels, eucalyptus excluded salt from its root zone, unlike either maple species. Eucalyptus maintained intact, undamaged leaves with no effect on photosynthesis but with minor reductions in stomatal conductance (gS). Conversely, bigleaf maple suffered increasing leaf damage, nearly defoliated at the highest levels, with decreasing gas exchange as salt concentration increased. Canyon maple leaves were not damaged and gas exchange was minimally affected at 3 dS·m−1 but showed increasing damage at higher salt concentration. Salt-tolerant eucalyptus and riparian bigleaf maple framed canyon maple’s moderate salt tolerance up to 3 dS·m−1 that appears related to seasonal soil drying in its semiarid native habitat. These results highlight the potential to infer a degree of salt tolerance from either native habitat or known drought tolerance in selecting plant species for urban landscapes limited by soil salinity or brackish irrigation water. Observable cues such as xeri-morphic leaf traits may also provide visual evidence of salt tolerance.

Polymyxa betae Keskin is the only natural transmitting vector of the Beet necrotic yellow vein virus (BNYVV) among the cultivated sugar beet. This work aims to study the impact of salt stress on fungus-virus-host relationships. The fungal infected fine roots of sugar beet plant naturally infected with BNYVV were collected and treated with different salt concentrations (0, 2000, 4000, 6000 and 8000 ppm) of NaCl for one day prior to mixing it with a sterile soil. After virus symptoms appeared on leaves, disease severity has been determined, leave and roots tissues were collected for BNYVV detection. It was found that severe symptoms on sugar beet inoculated with treated roots by low salt concentrations (2000 and 4000 ppm) while at high salt concentrations, 8000 ppm less injury approximately as control treated with H2O. On the other hand it was found the cystosorial colonization was increased in low salt concentrations (2000 and 4000 ppm) while decrease in high salt concentrations (6000 and 8000 ppm) especially in 8000 ppm. The same trend results were observed in virus concentration in roots where as the BNYVV concentration was increased in low salt concentrations (2000 and 4000 ppm) while decrease in high salt concentrations (6000 and 8000 ppm). So the relation between capacity of fungal vector to infect the plant by virus and salinity concentration are antagonistic. Soil salinity extremes most often lead to decrease infection of BNYVV via effect on fungal zoospore. Key words: Polymyxa betae, sugar beet, rhizomania, beet necrotic yellow vein virus (BNYVV), salinity.

For plants and other species alike, phosphorus (P) is the second most essential macronutrient. However, it becomes unavailable to plants because of its fixation with soil collisions, and hence cannot enter the food chain. In a pot trial, the impact of mycorrhizae and various organic amendments on P uptake and plant growth of spinach (Spinacia oleracea) was assessed. Farmyard manure (FYM), biogas slurry (BGS), and compost were used as organic amendments at a rate of 1.5% w/w in each treatment, along with mycorrhizae. Mycorrhizae and organic amendments applied together were found to boost plant growth and increase P uptake. FYM + mycorrhizae and BGS + mycorrhizae combinations resulted in increased root length, shoot height, shoot fresh weight, root fresh weight and leaf area. BGS + mycorrhizae combinations also showed increased P absorption, leading to higher photosynthetic activity and biomass. Mycorrhizae and organic amendments were shown to increase P uptake by as much as 42.25% and plant growth by 57.39%. We concluded that using this strategy in the field can be an economically viable option while also lowering the potential for negative environmental effects caused by the overuse of chemical fertilizers

In this article, interactions between Bacillus subtilis single-stranded DNA binding proteins (BsSSB) and single-stranded DNA (ssDNA) were systematically studied. The effect of different molar ratios between BsSSB and ssDNA on their binding modes was first investigated by electrophoretic mobility shift assays (EMSAs). It is found that a high molar ratio of BsSSB to ssDNA can produce BsSSB-ssDNA complexes formed in the mode of two proteins binding one 65-nt (nucleotide) ssDNA whereas a low molar ratio facilitates the formation of BsSSB-ssDNA complexes in the mode of one protein binding one 65-nt ssDNA. Furthermore, two binding modes are in dynamic equilibrium. The unbinding force of BsSSB-ssDNA complexes was measured quantitatively in solutions with different salt concentrations by using AFM-based single-molecule force spectroscopy (SMFS). Our results show that the unbinding force is about 10 pN higher at high salt concentration (0.5 M NaCl) than at low salt concentration (0.1 M NaCl) and the lifetime of BsSSB-ssDNA complexes at high salt concentration is twice as long as that at low salt concentration. These results indicate that more tightly packed BsSSB-ssDNA complexes can form at high salt (0.5 M NaCl) concentration. In addition, the results of EMSA show that ssDNA, which is bound to BsSSB, can dissociate from BsSSB in the presence of the cDNA strand, indicating the dynamic nature of BsSSB-ssDNA interactions.

Summary The effects of salinity on some agro-physiological properties, such as dry matter, nutrient contents, chlorophyll contents, and ionic balance, of maize plants were investigated. Plants were treated with six salt sources (NaCl, Na 2 SO 4 , CaCl 2 , CaSO 4 , MgCl 2 and MgSO 4 ) at four concentrations (0, 40, 80 and 120 mM) for 30 days in a growth medium. Salt type and concentration affected soil pH and electrical conductivity. Soil salinity affected the parameters considered and changed the nutrient balance of the plants. High salt concentration caused substantial reduction in plant growth. Different salt concentrations negatively affected plant dry weight. The highest decrease rates of plant dry weight were obtained for NaCl application followed by Na 2 SO 4 , CaCl 2 , MgCl 2 , CaSO 4 and MgSO 4 . Total chlorophyll and nitrate contents of the plants decreased with increasing salt concentrations, and the lowest value was obtained for NaCl application. Proline contents of the plants were increased with increasing salt concentrations, and the highest value was obtained for 120 mM NaCl application. The effects of salt concentrations on N, K and P contents of the plants were significant. The highest reduction rate was determined with NaCl application, but the lowest with MgSO 4 . Fe, Mn and Cu contents of the plants showed similar variation: the highest reduction was recorded with NaCl and the lowest with CaCl 2 . The highest decrease in Zn content occurred with MgSO 4 application, but the lowest with NaCl.

Soil salinity is a major abiotic factor which adversely affects the crop growth and productivity worldwide. Higher salt concentration caused ion imbalance and hyperosmotic stress which often lead to oxidative stress in plants. Soil salinization is mainly due to the poor irrigation management practices and natural causes. A total 20 % of the world’s cultivated lands and almost half of all irrigated lands are affected by high salinity. This chapter begins by stressing the importance of research into plant salt tolerance. After a brief outline of salinity-induced damage to both agricultural yield and growth of plants, strategies which plants adopt to deal with salinity are discussed, and current biotechnological efforts towards producing salt-tolerant crops are summarized. Particular attention is paid towards the application of plant growth-promoting bacteria in agriculture system for producing salt stress-tolerant crops and a fundamental understanding towards the mechanisms of beneficial plant–microbe interaction in the presence of salt.

Soil salinization is a widespread hindrance that endangers agricultural production and ecological security. High salt concentrations in saline soils are primarily caused by osmotic stress, ionic toxicity and oxidative stress, which have a negative impact on plant growth and development. In order to withstand salt stress, plants have developed a series of complicated physiological and molecular mechanisms, encompassing adaptive changes in the structure and function of various plant organs, as well as the intricate signal transduction networks enabling plants to survive in high-salinity environments. This review summarizes the recent advances in salt perception under different tissues, physiological responses and signaling regulations of plant tolerance to salt stress. We also examine the current knowledge of strategies for breeding salt-tolerant plants, including the applications of omics technologies and transgenic approaches, aiming to provide the basis for the cultivation of salt-tolerant crops through molecular breeding. Finally, future research on the application of wild germplasm resources and muti-omics technologies to discover new tolerant genes as well as investigation of crosstalk among plant hormone signaling pathways to uncover plant salt tolerance mechanisms are also discussed in this review.