Physiological and Biochemical Responses to Salt Stress of Alfalfa Populations Selected for Salinity Tolerance and Grown in Symbiosis with Salt-Tolerant Rhizobium

Alfalfa and its rhizobial symbiont are sensitive to salinity. We compared the physiological responses of alfalfa populations inoculated with a salt-tolerant rhizobium strain, exposed to five NaCl concentrations (0, 20, 40, 80, or 160 mM NaCl). Two initial cultivars, Halo (H-TS0) and Bridgeview (B-TS0), and two populations obtained after three cycles of recurrent selection for salt tolerance (H-TS3 and B-TS3) were compared. Biomass, relative water content, carbohydrates, and amino acids concentrations in leaves and nodules were measured. The higher yield of TS3-populations than initial cultivars under salt stress showed the effectiveness of our selection method to improve salinity tolerance. Higher relative root water content in TS3 populations suggests that root osmotic adjustment is one of the mechanisms of salt tolerance. Higher concentrations of sucrose, pinitol, and amino acid in leaves and nodules under salt stress contributed to the osmotic adjustment in alfalfa. Cultivars differed in their response to recurrent selection: under a 160 mM NaCl-stress, aromatic amino acids and branched-chain amino acids (BCAAs) increased in nodules of B-ST3 as compared with B-TS0, while these accumulations were not observed in H-TS3. BCAAs are known to control bacteroid development and their accumulation under severe stress could have contributed to the high nodulation of B-TS3.

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Physiological characterisation and fine mapping of a salt-tolerant mutant in rice (Oryza sativa)

Functional Plant Biology ◽

10.1071/fp15126 ◽

2015 ◽

Vol 42 (11) ◽

pp. 1026 ◽

Cited By ~ 11

Author(s):

Ping Deng ◽

Dan Jiang ◽

Yanmin Dong ◽

Xingyu Shi ◽

Wen Jing ◽

...

Keyword(s):

Oryza Sativa ◽

Salt Stress ◽

Salt Tolerance ◽

Oryza Sativa L ◽

Recessive Gene ◽

Nacl Stress ◽

Shoot Biomass ◽

Salt Tolerant ◽

Candidate Locus ◽

F2 Population

Salt-tolerant mutants are valuable resources for basic and applied research on plant salt tolerance. Here, we report the isolation and characterisation of a salt-tolerant rice (Oryza sativa L.) mutant. This mutant was identified from an ethyl methanesulfonate-induced Nipponbare mutant library, designated as rice salt tolerant 1 (rst1). The rst1 mutant was tolerant to salt stress and showed significantly higher shoot biomass and chlorophyll content, but lower lipid peroxidation and electrolyte leakage under NaCl stress. The improved salt tolerance of this mutant may be due mainly to its enhanced ability to restrict Na+ accumulation in shoots under salt stress conditions. Genetic analysis indicated that the salt tolerance of the rst1 mutant was controlled by a single recessive gene. Quantitative trait locus (QTL) mapping for salt tolerance was performed using an F2 population of rst1 × Peiai 64. Two QTLs were detected, in which the locus on chromosome 6 was determined to be the candidate locus of the rst1 gene. The rst1 locus was subsequently shown to reside within a 270.4-kb region defined by the markers IM29432 and IM29702. This result will be useful for map-based cloning of the rst1 gene and for marker-assisted breeding for salt tolerance in rice.

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Genomic and transcriptomic analysis reveal molecular basis of salinity tolerance in a novel strong salt-tolerant rice landrace Changmaogu

Rice ◽

10.1186/s12284-019-0360-4 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 3

Author(s):

Bing-Rui Sun ◽

Chong-Yun Fu ◽

Zhi-Lan Fan ◽

Yu Chen ◽

Wen-Feng Chen ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Salinity Tolerance ◽

Molecular Basis ◽

Carotenoid Biosynthesis ◽

Seedling Stage ◽

Differentially Expressed ◽

Salt Tolerant ◽

Transcriptomic Sequencing ◽

Rice Landrace

Abstract Background Salt stress is an important factor that limits rice yield. We identified a novel, strongly salt tolerant rice landrace called Changmaogu (CMG) collected from a coastal beach of Zhanjiang, Guangdong Province, China. The salt tolerance of CMG was much better than that of the international recognized salt tolerant rice cultivar Pokkali in the germination and seedling stages. Results To understand the molecular basis of salt tolerance in CMG, we performed BSA-seq for two extreme bulks derived from the cross between CMG and a cultivar sensitive to salt, Zhefu802. Transcriptomic sequencing was conducted for CMG at the germination and young seedling stages. Six candidate regions for salt tolerance were mapped on Chromosome 1 by BSA-seq using the extreme populations. Based on the polymorphisms identified between both parents, we detected 32 genes containing nonsynonymous coding single nucleotide polymorphisms (SNPs) and frameshift mutations in the open reading frame (ORF) regions. With transcriptomic sequencing, we detected a large number of differentially expressed genes (DEGs) at the germination and seedling stages under salt stress. KEGG analysis indicated two of 69 DEGs shared at the germination and seedling stages were significantly enriched in the pathway of carotenoid biosynthesis. Of the 169 overlapping DEGs among three sample points at the seedling stage, 13 and six DEGs were clustered into the pathways of ABA signal transduction and carotenoid biosynthesis, respectively. Of the 32 genes carrying sequence variation, only OsPP2C8 (Os01g0656200) was differentially expressed in the young seedling stage under salt stress and also showed sequence polymorphism in the ORFs between CMG and Zhefu802. Conclusion OsPP2C8 was identified as the target candidate gene for salinity tolerance in the seedling stage. This provides an important genetic resource for the breeding of novel salt tolerant rice cultivars.

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Chitosan regulates metabolic balance, polyamine accumulation, and Na+ transport contributing to salt tolerance in creeping bentgrass

BMC Plant Biology ◽

10.1186/s12870-020-02720-w ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Wan Geng ◽

Zhou Li ◽

Muhammad Jawad Hassan ◽

Yan Peng

Keyword(s):

Amino Acids ◽

Salt Stress ◽

Salt Tolerance ◽

Antioxidant Enzyme ◽

Osmotic Adjustment ◽

Photochemical Efficiency ◽

Creeping Bentgrass ◽

Antioxidant Enzyme Activities ◽

Metabolic Balance ◽

Gaba Accumulation

Abstract Background Chitosan (CTS), a natural polysaccharide, exhibits multiple functions of stress adaptation regulation in plants. However, effects and mechanism of CTS on alleviating salt stress damage are still not fully understood. Objectives of this study were to investigate the function of CTS on improving salt tolerance associated with metabolic balance, polyamine (PAs) accumulation, and Na+ transport in creeping bentgrass (Agrostis stolonifera). Results CTS pretreatment significantly alleviated declines in relative water content, photosynthesis, photochemical efficiency, and water use efficiency in leaves under salt stress. Exogenous CTS increased endogenous PAs accumulation, antioxidant enzyme (SOD, POD, and CAT) activities, and sucrose accumulation and metabolism through the activation of sucrose synthase and pyruvate kinase activities, and inhibition of invertase activity. The CTS also improved total amino acids, glutamic acid, and γ-aminobutyric acid (GABA) accumulation. In addition, CTS-pretreated plants exhibited significantly higher Na+ content in roots and lower Na+ accumulation in leaves then untreated plants in response to salt stress. However, CTS had no significant effects on K+/Na+ ratio. Importantly, CTS enhanced salt overly sensitive (SOS) pathways and also up-regulated the expression of AsHKT1 and genes (AsNHX4, AsNHX5, and AsNHX6) encoding Na+/H+ exchangers under salt stress. Conclusions The application of CTS increased antioxidant enzyme activities, thereby reducing oxidative damage to roots and leaves. CTS-induced increases in sucrose and GABA accumulation and metabolism played important roles in osmotic adjustment and energy metabolism during salt stress. The CTS also enhanced SOS pathway associated with Na+ excretion from cytosol into rhizosphere, increased AsHKT1 expression inhibiting Na+ transport to the photosynthetic tissues, and also up-regulated the expression of AsNHX4, AsNHX5, and AsNHX6 promoting the capacity of Na+ compartmentalization in roots and leaves under salt stress. In addition, CTS-induced PAs accumulation could be an important regulatory mechanism contributing to enhanced salt tolerance. These findings reveal new functions of CTS on regulating Na+ transport, enhancing sugars and amino acids metabolism for osmotic adjustment and energy supply, and increasing PAs accumulation when creeping bentgrass responds to salt stress.

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Salt Tolerant Gossypium hirsutum L. Cultivars are Mostly Long-Staple Length Cultivars

10.21203/rs.3.rs-1210602/v1 ◽

2022 ◽

Author(s):

Rachel Predeepa ◽

Ranjith Kumar ◽

George C. Abraham ◽

T. S. Subramanian

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Gossypium Hirsutum ◽

Salinity Tolerance ◽

Molecular Techniques ◽

Salt Tolerant ◽

Cotton Lint ◽

Cropping Season ◽

Cotton Plants ◽

Staple Length

Abstract Background: Cotton is a major cash crop in the global and, in particular, the Indian markets, playing an important economic role in the textile and oil industries. The cotton plant is one of the highly bred plants that is highly sensitive to salt stress. As cotton is a non-food crop, the availability of non-saline terrain and water for the cultivation of cotton plants is only next to other food crops, thereby posing a need to better understand the salt tolerance of this plant. Gossypium hirsutum L. cultivars MCU 5, LRA 5166, and SVPR 2 were selected based on exomorphic traits like staple length and cropping season so that the genotypic responses to salt stress and salt shock can be compared for interpreting the effects of salinity on in vitro germination. Thus, this study aims to establish genotypic dependence on salinity tolerance. Results: The results affirmed genotypic variation in salinity tolerance, with MCU 5 tolerating salt stress better than LRA 5166 and SVPR 2 in all the observed stages of growth of the plant and the parameters measured. Further salt-tolerant cotton varieties were observed to be long-staple length varieties; staple length is the fiber character of the cotton lint. Moreover, salt tolerance in the vegetative growth stage of cotton plants is not independent of the germination stage of the plant.Conclusion: Nevertheless, the correlation of genotypic dependence to morphological characteristics, in particular, staple length (and cropping season), is of agronomic and commercial significance. Further research by screening and investigating a greater number of cultivars using biochemical and molecular techniques will provide a better understanding of this observed phenotypical relationship to the genotypes of cotton cultivars under salt stress.

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Stomatal and Metabolic Limitations to Photosynthesis Resulting from NaCl Stress in Perennial Ryegrass Genotypes Differing in Salt Tolerance

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.138.5.350 ◽

2013 ◽

Vol 138 (5) ◽

pp. 350-357 ◽

Cited By ~ 9

Author(s):

Tao Hu ◽

Haiying Yi ◽

Longxing Hu ◽

Jinmin Fu

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Perennial Ryegrass ◽

Stress Responses ◽

Large Subunit ◽

Nacl Stress ◽

Expression Level ◽

Transcriptional Level ◽

Salt Tolerant ◽

Rubisco Activity

Plants possess abiotic stress responses that alter photosynthetic metabolism under salinity stress. The objective of this study was to identify the stomatal and metabolic changes associated with photosynthetic responses to NaCl stress in perennial ryegrass (Lolium perenne). Five-week-old seedlings of two perennial ryegrass genotypes, PI 516605 (salt-sensitive) and BARLP 4317 (salt-tolerant), were subjected to 0 and 250 mm NaCl for 8 days. The salt tolerance in perennial ryegrass was significantly associated with leaf relative water content (RWC) and photosynthetic capacity through the maintenance of greater metabolic activities under prolonged salt stress. BARLP 4317 maintained greater turf quality, RWC, and stomatal limitations but a lower level of lipid peroxidation [malondialdehyde (MDA)] and intercellular CO2 concentration than PI 516605 at 8 days after treatment (DAT). Ribulose-1, 5-bisphosphate carboxylase:oxygenase (Rubisco) activity and activation state, transcriptional level of rbcL gene, and expression level of Rubisco large subunit (LSU) declined in stressed perennial ryegrass but were higher in salt-tolerant genotype at 8 DAT. Furthermore, photosynthetic rate increased linearly with increasing Rubisco activity, Rubisco activation state, and RWC in both genotypes. The same linear relationship was found between RWC and Rubisco activity. However, MDA content decreased linearly with increasing RWC in both genotypes. Salinity-induced inhibition of photosynthesis in perennial ryegrass was mainly the result of stomatal limitation during early salt stress and metabolic limitation associated with the inhibition of RWC, activity of Rubisco, expression level of rbcL gene, and LSU under a prolonged period of severe salinity.

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Application of SSR Technique for the Identification of Markers Linked to Salinity Tolerance in Rice

Progressive Agriculture ◽

10.3329/pa.v19i2.16929 ◽

2013 ◽

Vol 19 (2) ◽

pp. 57-65

Author(s):

MH Kabir ◽

MM Islam ◽

SN Begum ◽

AC Manidas

Keyword(s):

Salt Tolerance ◽

Ssr Markers ◽

Salinity Tolerance ◽

Seedling Stage ◽

Phenotypic Screening ◽

Salt Tolerant ◽

Marker Assisted Breeding ◽

Hydroponic System ◽

Rice Landrace ◽

Salt Susceptible

A cross was made between high yielding salt susceptible BINA variety (Binadhan-5) with salt tolerant rice landrace (Harkuch) to identify salt tolerant rice lines. Thirty six F3 rice lines of Binadhan-5 x Harkuch were tested for salinity tolerance at the seedling stage in hydroponic system using nutrient solution. In F3 population, six lines were found as salt tolerant and 10 lines were moderately tolerant based on phenotypic screening at the seedling stage. Twelve SSR markers were used for parental survey and among them three polymorphic SSR markers viz., OSR34, RM443 and RM169 were selected to evaluate 26 F3 rice lines for salt tolerance. With respect to marker OSR34, 15 lines were identified as salt tolerant, 9 lines were susceptible and 2 lines were heterozygous. While RM443 identified 3 tolerant, 14 susceptible and 9 heterozygous rice lines. Eight tolerant, 11 susceptible and 7 heterozygous lines were identified with the marker RM169. Thus the tested markers could be efficiently used for tagging salt tolerant genes in marker-assisted breeding programme.DOI: http://dx.doi.org/10.3329/pa.v19i2.16929 Progress. Agric. 19(2): 57 - 65, 2008

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Genetic Potential for Salt Tolerance During Germination in Lycopersicon Species

HortScience ◽

10.21273/hortsci.32.2.296 ◽

1997 ◽

Vol 32 (2) ◽

pp. 296-300 ◽

Cited By ~ 46

Author(s):

M.R. Foolad ◽

G.Y. Lin

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Genotypic Variation ◽

Control Treatment ◽

Molar Ratio ◽

Wild Accession ◽

Salt Tolerant ◽

Plant Introductions ◽

Genetic Potential ◽

Stress Levels

Seed of 42 wild accessions (Plant Introductions) of Lycopersicon pimpinellifolium Jusl., 11 cultigens (cultivated accessions) of L. esculentum Mill., and three control genotypes [LA716 (a salt-tolerant wild accession of L. pennellii Corr.), PI 174263 (a salt-tolerant cultigen), and UCT5 (a salt-sensitive breeding line)] were evaluated for germination in either 0 mm (control) or 100 mm synthetic sea salt (SSS, Na+/Ca2+ molar ratio equal to 5). Germination time increased in response to salt-stress in all genotypes, however, genotypic variation was observed. One accession of L. pimpinellifolium, LA1578, germinated as rapidly as LA716, and both germinated more rapidly than any other genotype under salt-stress. Ten accessions of L. pimpinellifolium germinated more rapidly than PI 174263 and 35 accessions germinated more rapidly than UCT5 under salt-stress. The results indicate a strong genetic potential for salt tolerance during germination within L. pimpinellifolium. Across genotypes, germination under salt-stress was positively correlated (r = 0.62, P < 0.01) with germination in the control treatment. The stability of germination response at diverse salt-stress levels was determined by evaluating germination of a subset of wild, cultivated accessions and the three control genotypes at 75, 150, and 200 mm SSS. Seeds that germinated rapidly at 75 mm also germinated rapidly at 150 mm salt. A strong correlation (r = 0.90, P < 0.01) existed between the speed of germination at these two salt-stress levels. At 200 mm salt, most accessions (76%) did not reach 50% germination by 38 days, demonstrating limited genetic potential within Lycopersicon for salt tolerance during germination at this high salinity.

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Evaluation of salinity tolerance indices in North African barley accessions at reproductive stage

Czech Journal of Genetics and Plant Breeding ◽

10.17221/50/2017-cjgpb ◽

2019 ◽

Vol 55 (No. 2) ◽

pp. 61-69 ◽

Cited By ~ 3

Author(s):

Dorsaf Allel ◽

Anis BenAmar ◽

Mounawer Badri ◽

Chedly Abdelly

Keyword(s):

Salt Tolerance ◽

Grain Yield ◽

Salinity Tolerance ◽

Selection Criteria ◽

Reproductive Stage ◽

Shoot Biomass ◽

Salt Tolerant ◽

North African ◽

Grain Number ◽

Selection Indices

Soil salinity is one of the main factors limiting cereal productivity in worldwide agriculture. Exploitation of natural variation in local barley germplasm is an effective approach to overcome yield losses. Three gene pools of North African Hordeum vulgare L. grown in Tunisia, Algeria and Egypt were evaluated at the reproductive stage under control and saline conditions. Assessment of stress tolerance was monitored using morphological, yield-related traits and phenological parameters of reproductive organs showing significant genetic variation. High heritability and positive relationships were found suggesting that some traits associated with salt tolerance could be used as selection criteria. The phenotypic correlations revealed that vegetative traits including shoot biomass, tiller number and leaf number along with yield-related traits such as spike number, one spike dry weight, grain number/plant and grain number/spike were highly positively correlated with grain yield under saline conditions. Hence, these traits can be used as reliable selection criteria to improve barley grain yield. Keeping a higher shoot biomass and longer heading and maturity periods as well as privileged filling ability might contribute to higher grain production in barley and thus could be potential target traits in barley crop breeding toward improvement of salinity tolerance. Multiple selection indices revealed that salt tolerance trait index provided a better discrimination of barley landraces allowing selection of highly salt-tolerant and highly productive genotypes under severe salinity level. Effective evaluation of salt tolerance requires an integration of selection indices to successfully identify and characterize salt tolerant lines required for valuable exploitation in the management of salt-affected areas.

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Early Growth Stage Characterization and the Biochemical Responses for Salinity Stress in Tomato

Plants ◽

10.3390/plants10040712 ◽

2021 ◽

Vol 10 (4) ◽

pp. 712

Author(s):

Md Sarowar Alam ◽

Mark Tester ◽

Gabriele Fiene ◽

Magdi Ali Ahmed Mousa

Keyword(s):

Salt Tolerance ◽

Salinity Tolerance ◽

Salinity Treatment ◽

Salt Tolerant ◽

Improvement Program ◽

Biochemical Basis ◽

Elevated Salinity ◽

Tolerance Indices ◽

Promising Source ◽

Tomato Genotypes

Salinity is one of the most significant environmental stresses for sustainable crop production in major arable lands of the globe. Thus, we conducted experiments with 27 tomato genotypes to screen for salinity tolerance at seedling stage, which were treated with non-salinized (S1) control (18.2 mM NaCl) and salinized (S2) (200 mM NaCl) irrigation water. In all genotypes, the elevated salinity treatment contributed to a major depression in morphological and physiological characteristics; however, a smaller decrease was found in certain tolerant genotypes. Principal component analyses (PCA) and clustering with percentage reduction in growth parameters and different salt tolerance indices classified the tomato accessions into five key clusters. In particular, the tolerant genotypes were assembled into one cluster. The growth and tolerance indices PCA also showed the order of salt-tolerance of the studied genotypes, where Saniora was the most tolerant genotype and P.Guyu was the most susceptible genotype. To investigate the possible biochemical basis for salt stress tolerance, we further characterized six tomato genotypes with varying levels of salinity tolerance. A higher increase in proline content, and antioxidants activities were observed for the salt-tolerant genotypes in comparison to the susceptible genotypes. Salt-tolerant genotypes identified in this work herald a promising source in the tomato improvement program or for grafting as scions with improved salinity tolerance in tomato.

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Physiological and transcriptomic analyses reveal the mechanisms underlying the salt tolerance of Zoysia japonica Steud.

10.21203/rs.2.16313/v3 ◽

2020 ◽

Author(s):

Jingjing Wang ◽

Cong An ◽

Hailin Guo ◽

Xiangyang Yang ◽

Jingbo Chen ◽

...

Keyword(s):

Signal Transduction ◽

Salt Stress ◽

Stress Response ◽

Salt Tolerance ◽

Molecular Mechanisms ◽

Salt Tolerant ◽

Zoysia Japonica ◽

Salt Stress Response ◽

Leaves And Roots ◽

Time Point

Abstract Background: Areas with saline soils are sparsely populated and have fragile ecosystems, which severely restricts the sustainable development of local economies. Zoysia grasses are recognized as excellent warm-season turfgrasses worldwide, with high salt tolerance and superior growth in saline-alkali soils. However, the mechanism underlying the salt tolerance of Zoysia species remains unknown. Results: The phenotypic and physiological responses of two contrasting materials, Zoysia japonica Steud. Z004 (salt sensitive) and Z011 (salt tolerant) in response to salt stress were studied. The results show that Z011 was more salt tolerant than was Z004, with the former presenting greater K+/Na+ ratios in both its leaves and roots. To study the molecular mechanisms underlying salt tolerance further, we compared the transcriptomes of the two materials at different time points (0 h, 1 h, 24 h, and 72 h) and from different tissues (leaves and roots) under salt treatment. The 24-h time point and the roots might make significant contributions to the salt tolerance. Moreover, GO and KEGG analyses of different comparisons revealed that the key DEGs participating in the salt-stress response belonged to the hormone pathway, various TF families and the DUF family. Conclusions: Z011 may have improved salt tolerance by reducing Na+ transport from the roots to the leaves, increasing K+ absorption in the roots and reducing K+ secretion from the leaves to maintain a significantly greater K+/Na+ ratio. Twenty-four hours might be a relatively important time point for the salt-stress response of zoysiagrass. The auxin signal transduction family, ABA signal transduction family, WRKY TF family and bHLH TF family may be the most important families in Zoysia salt-stress regulation. This study provides fundamental information concerning the salt-stress response of Zoysia and improves the understanding of molecular mechanisms in salt-tolerant plants.

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