Salt Stress In Soybean Research Articles

Changes in photosynthesis and chlorophyll fluorescence in two soybean (Glycine max) varieties under NaCl stress

Traditional detection methods of crop information are often destructive and low efficiency. In this study, a new evaluation method was developed based on photosynthesis and chlorophyll fluorescence. Via analysis of the changes under NaCl stress during the seedling stage of two varieties, the salt resistance mechanism of soybeans was explored and a non-destructive stress-recognition method was developed. In this experiment, two soybean varieties were treated with one of four levels of NaCl stress: CK (0 mmol/L), LS (50 mmol/L), MS (100 mmol/L), and HS (150 mmol/L), for 15 d. The normal functions of the photosynthetic system of soybeans were enhanced under LS NaCl stress, but were inhibited under HS NaCl stress. Biomass, net leaf photosynthetic rate (Pn), stomatal conductance (gs), intercellular carbon dioxide concentration (Ci), transpiration rate (Tr), chlorophyll fluorescence parameters Y(II) and PSII decreased. However, in contrast to the findings of other studies on the influence of severe drought stress on soybean for long periods in which non-photochemical quenching coefficient (qN) decreased, this parameter increased under salt stress in soybean. The results demonstrate that the method developed is a promising tool for rapid and non-destructive detection of soybean photosynthetic responses under salt stress in the field. Keywords: biomass, chlorophyll fluorescence parameters, NaCl stress, photosynthetic parameters, soybean DOI: 10.25165/j.ijabe.20211403.5941 Citation: Luo B, Wang C, Wang X D, Zhang H, Zhou Y N, Wang W S, et al. Changes in photosynthesis and chlorophyll fluorescence in two soybean (Glycine max) varieties under NaCl stress. Int J Agric & Biol Eng, 2021; 14(3): 76–82.

Changes in photosynthesis and chlorophyll fluorescence in two soybean (Glycine max) varieties under NaCl stress

Traditional detection methods of crop information are often destructive and low efficiency. In this study, a new evaluation method was developed based on photosynthesis and chlorophyll fluorescence. Via analysis of the changes under NaCl stress during the seedling stage of two varieties, the salt resistance mechanism of soybeans was explored and a non-destructive stress-recognition method was developed. In this experiment, two soybean varieties were treated with one of four levels of NaCl stress: CK (0 mmol/L), LS (50 mmol/L), MS (100 mmol/L), and HS (150 mmol/L), for 15 d. The normal functions of the photosynthetic system of soybeans were enhanced under LS NaCl stress, but were inhibited under HS NaCl stress. Biomass, net leaf photosynthetic rate (Pn), stomatal conductance (gs), intercellular carbon dioxide concentration (Ci), transpiration rate (Tr), chlorophyll fluorescence parameters Y(II) and PSII decreased. However, in contrast to the findings of other studies on the influence of severe drought stress on soybean for long periods in which non-photochemical quenching coefficient (qN) decreased, this parameter increased under salt stress in soybean. The results demonstrate that the method developed is a promising tool for rapid and non-destructive detection of soybean photosynthetic responses under salt stress in the field. Keywords: biomass, chlorophyll fluorescence parameters, NaCl stress, photosynthetic parameters, soybean DOI: 10.25165/j.ijabe.20211403.5941 Citation: Luo B, Wang C, Wang X D, Zhang H, Zhou Y N, Wang W S, et al. Changes in photosynthesis and chlorophyll fluorescence in two soybean (Glycine max) varieties under NaCl stress. Int J Agric & Biol Eng, 2021; 14(3): 76–82.

Exogenous Selenium Mitigates Salt Stress in Soybean by Improving Growth, Physiology, Glutathione Homeostasis and Antioxidant Defense

The mechanism of selenium (Se)-induced salt tolerance was studied in moderately sensitive soybean (Glycine max L.) plants. To execute this view, soybean plants were imposed with salt stress (EC 6 dS m−1 ) applying NaCl. ... | Find, read and cite all the research you need on Tech Science Press

Stress induced dynamic adjustment of conserved miR164:NAC module.

Salinity and drought are the two major stresses limiting the productivity of economically important crops such as Glycine max (soybean). The incidence of these stresses during the pod development stages affects the quality and quantity of seeds, which compromise the yield of soybean. The miR164:NAC module has been shown to play a critical role in regulating the response to salt and drought stress in several plant species. However, biological role of miR164:NAC module in salt stress in soybean is not fully understood. In this study, we identified 215 salt responsive miRNAs, using miScript miRNA array with a sensitive and a tolerant soybean genotype, William82 and INCASoy36, respectively. The targets of these salt regulated miRNAs were searched in the degradome datasets. It was found that four salt stress deregulated miRNAs targeted the NAC transcription factor and among these miR164k and miR408d showed antagonistic expression in the two soybean genotypes. The expression of miR164k was higher in salt tolerant INCASoy36 as compared to salt sensitive William82, under unstressed conditions. However under salt stress, miR164k was downregulated in INCASoy36 (-2.65 fold), whereas it was upregulated in William82 (4.68 fold). A transient co-expression assay validated that gma-miR164k directs the cleavage of GmNAC1 transcript. Bioinformatics analysis revealed that the regulation of NAC transcription factor family by members of miR164 family is conserved across many species. The dynamic expression profiles of miR164 and NAC-TFs were captured in different tissues of rice, tobacco, and two soybean genotypes under drought and salt stress conditions. Collectively, our results suggest that genetically determined dynamic modulation of the conserved miR164:NAC-TF module may play an important role in determining the adaptive response of plants to stress.

Dynamic Changes in Genome-Wide Histone3 Lysine27 Trimethylation and Gene Expression of Soybean Roots in Response to Salt Stress.

Soybean is an important economic crop for human diet, animal feeds and biodiesel due to high protein and oil content. Its productivity is significantly hampered by salt stress, which impairs plant growth and development by affecting gene expression, in part, through epigenetic modification of chromatin status. However, little is known about epigenetic regulation of stress response in soybean roots. Here, we used RNA-seq and ChIP-seq technologies to study the dynamics of genome-wide transcription and histone methylation patterns in soybean roots under salt stress. Eight thousand seven hundred ninety eight soybean genes changed their expression under salt stress treatment. Whole-genome ChIP-seq study of an epigenetic repressive mark, histone H3 lysine 27 trimethylation (H3K27me3), revealed the changes in H3K27me3 deposition during the response to salt stress. Unexpectedly, we found that most of the inactivation of genes under salt stress is strongly correlated with the de novo establishment of H3K27me3 in various parts of the promoter or coding regions where there is no H3K27me3 in control plants. In addition, the soybean histone modifiers were identified which may contribute to de novo histone methylation and gene silencing under salt stress. Thus, dynamic chromatin regulation, switch between active and inactive modes, occur at target loci in order to respond to salt stress in soybean. Our analysis demonstrates histone methylation modifications are correlated with the activation or inactivation of salt-inducible genes in soybean roots.

Identification of responsive miRNAs involved in combination stresses of phosphate starvation and salt stress in soybean root

Salt stress and phosphate (Pi) starvation severely affect plants growth and development. MicroRNAs involved in single stress of Pi starvation or salt stress have been reported in many plant species. However, the combination stresses of Pi starvation and salt stress responsive microRNAs and their target genes have not been reported. In the study, we generated 7 small RNA libraries under 4 different treatments with three independent biological replicates: CK, salt stress (SR1, SR5), Pi starvation (LPR1, LPR5), and the double stresses of salt stress/Pi starvation (DR1, DR5) in soybean root by using Illumina HiSeqTM2000 sequencing technique. Total of 5285 miRNAs including 3616 conserved and 1669 novel miRNAs were identified. Among them, 21 miRNAs including gma-miR169l-3p, gma-miR5036, gma-miR862a, and gma-398a/b, were detected to respond to the single stress and the double stresses of Pi starvation and salt stress. The target genes for the identified miRNAs such as ethylene-responsive transcription factor 4, protein phosphatase 2C, and superoxide dismutase [Cu-Zn], were classified into different biological processes including metabolic process, signaling transduction. The expression patterns of several identified miRNAs were validated by RT-qPCR and the results of RT-qPCR were consistent with the result of IlluminaHiSeq. The Na+, K+, and PO43− contents under different treatments were detected in soybean roots and leaves. Our findings identified the differentially expressed miRNAs in response to the combination stresses of Pi starvation and salt stress, which providing the essential information for enhancing the resistance to salt stress and Pi starvation in soybean.

Comparative Transcriptional Profiling of Soybean Orthologs of Arabidopsis Trichome Developmental Genes under Salt Stress

The aim of this study was to determine the ultrastructural changes and regulation of trichome-metabolism-related genes against salt stress in soybean (Glycine max L. Merr.) plants. The 14-day-old Ataem-7 and S04-05 soybean seedlings were subjected to 0, 50, 100, and 150 mM NaCl stress. While the chlorophyll quantities were reduced, the activities of guaiacol peroxidase were increased in both varieties due to increasing NaCl concentrations. In S04-05 soybean variety, trichome densities were increased on both surfaces of the leaves whereas decreases were recorded in Ataem-7 variety at 150 mM NaCl treatment. Stomatal densities were increased on both surfaces of the leaves of both soybean varieties after salinity stress. We also performed a qRT-PCR analysis to evaluate the relative transcription levels of the soybean orthologs of Arabidopsis trichome developmental genes. qRT-PCR analysis demonstrated an induction of the soybean orthologs of GL2 and GL3 genes in soybean plants after 50, 100, and 150 mM NaCl treatments in both varieties. While the expression level of TTG1 ortholog gene was negatively affected in both soybean varieties under different concentrations of salinity, GL1 ortholog gene expression profile differed as a result of changing salt concentrations in both varieties with respect to control plants. It is observed that the regulation of trichome formation differs between two soybean varieties.

Interactive effects of aphid feeding and virus infection on host gene expression and volatile compounds in salt-stressed soybean, Glycine max (L.) Merr.

Saline soils are becoming an important limiting factor in production agriculture. Soybean cultivars [Glycine max (L.) Merr.] differ in their ability to tolerate salt stress with those that cannot limit ion uptake into leaves being salt sensitive. Those that can partially limit ion uptake into leaves are generally more salt tolerant. Soybean mosaic virus (SMV) is an important viral pathogen of soybean worldwide and is commonly transmitted by the soybean aphid, Aphis glycines Matsumura. In this study, we investigate the interaction of salt stress in soybean with SMV infection and infestation by the soybean aphid by measuring aphid populations in a no-choice assay, gene expression levels, and the induction of volatile organic compounds using static headspace GC–MS analysis. Salt stress and SMV infection both reduced total aphid populations, though SMV did not reduce the total number of aphids per gram of fresh weight. Aphid suppression of a calcium EF hand gene and OPR1 was lost when salt-sensitive soybean plants were salt stressed and when salt-tolerant plants were subjected to all three stressors. The relative levels of SMV in aphid-infested soybeans were increased by salt stress in the salt-sensitive cultivar, whereas SMV levels decreased in the salt-tolerant cultivar. Static headspace collection of volatile organic compounds revealed that salt stress and SMV infection had suppressive activities on aphid-induced terpenes. These results suggest that although salt stress has a negative impact on aphid population size, the changes in volatiles and SMV levels could alter the incidence of SMV in salt-stressed fields.

The miR172c-NNC1 module modulates root plastic development in response to salt in soybean

BackgroundPlant roots are highly plastic to high salinity. However, the molecular mechanism by which root developmental plasticity is regulated remains largely unknown. Previously we reported that miR172c-NNC1 module plays a key role in soybean-rhizobial symbiosis. The fact that the miR172c promoter contains several stress-related cis elements indicates that miR172c may have a role in root response to abiotic stress.ResultsHere we showed that miR172c is greatly induced by salt stress in soybean. Overexpression of miR172c and knockdown of miR172c activity resulted in substantially increased and reduced root sensitivity to salt stress, respectively. Furthermore, we show that the target gene NNC1 (Nodule Number Control 1) of miR172c was downregulated by salt stress. The transgenic roots overexpressing or knocking down NNC1 expression also exhibited the altered root sensitivity to salt stress.ConclusionThe study reveals the crucial role of miR172c-NNC1 module in root stress tolerance to salt stress in soybean.

Overexpression of GmFDL19 enhances tolerance to drought and salt stresses in soybean.

The basic leucine zipper (bZIP) family of transcription factors plays an important role in the growth and developmental process as well as responds to various abiotic stresses, such as drought and high salinity. Our previous work identified GmFDL19, a bZIP transcription factor, as a flowering promoter in soybean, and the overexpression of GmFDL19 caused early flowering in transgenic soybean plants. Here, we report that GmFDL19 also enhances tolerance to drought and salt stress in soybean. GmFDL19 was determined to be a group A member, and its transcription expression was highly induced by abscisic acid (ABA), polyethylene glycol (PEG 6000) and high salt stresses. Overexpression of GmFDL19 in soybean enhanced drought and salt tolerance at the seedling stage. The relative plant height (RPH) and relative shoot dry weight (RSDW) of transgenic plants were significantly higher than those of the WT after PEG and salt treatments. In addition, the germination rate and plant height of the transgenic soybean were also significantly higher than that of WT plants after various salt treatments. Furthermore, we also found that GmFDL19 could reduce the accumulation of Na+ ion content and up-regulate the expression of several ABA/stress-responsive genes in transgenic soybean. We also found that GmFDL19 overexpression increased the activities of several antioxidative enzyme and chlorophyll content but reduced malondialdehyde content. These results suggested that GmFDL19 is involved in soybean abiotic stress responses and has potential utilization to improve multiple stress tolerance in transgenic soybean.

Overexpression of AtSZF2 from Arabidopsis Showed Enhanced Tolerance to Salt Stress in Soybean

Overexpression of AtSZF2 from Arabidopsis Showed Enhanced Tolerance to Salt Stress in Soybean

Coordination between Bradyrhizobium and Pseudomonas alleviates salt stress in soybean through altering root system architecture

ABSTRACTIt is a well accepted strategy to improve plant salt tolerance through inoculation with beneficial microorganisms. However, its underlying mechanisms still remain unclear. In the present study, hydroponic experiments were conducted to evaluate the effects of Bradyrhizobium japonicum USDA 110 with salt-tolerant Pseudomonas putida TSAU1 on growth, protein content, nitrogen, and phosphorus uptake as well as root system architecture of soybean (Glycine max L.) under salt stress. The results indicated that the combined inoculation with USDA 110 and TSAU1 significantly improved plant growth, nitrogen and phosphorus contents, and contents of soluble leaf proteins under salt stress compared to the inoculation with the symbiont alone or compared to un-inoculated ones. The root architectural traits, like root length, surface area, project area, and root volume; as well as nodulation traits were also significantly increased by co-inoculation with USDA 110 and TSAU1. The plant-growth promoting rhizobacteria (PGPR) P. putida strain TSAU1 could improve the symbiotic interaction between the salt-stressed soybean and B. japonicum USDA 110. In conclusion, inoculation with B. japonicum and salt-tolerant P. putida synergistically improved soybean salt tolerance through altering root system architecture facilitating nitrogen and phosphorus acquisition, and nodule formation.

Genome-wide characterization of the ankyrin repeats gene family under salt stress in soybean

Ankyrin repeats (ANK) gene family are common in diverse organisms and play important roles in cell growth, development and response to environmental stresses. Recently, genome-wide identification and evolutionary analyses of the ANK gene family have been carried out in Arabidopsis, rice and maize. However, little is known about the ANK genes in the whole soybean genome. In this study, we described the identification and structural characterization of 162ANK genes in soybean (GmANK). Then, comprehensive bioinformatics analyses of GmANK genes family were performed including gene locus, phylogenetic, domain composition analysis, chromosomal localization and expression profiling. Domain composition analyses showed that GmANK proteins formed eleven subfamilies in soybean. In sicilo expression analysis of these GmANK genes demonstrated that GmANK genes show a diverse/various expression pattern, suggesting that functional diversification of GmANK genes family. Based on digital gene expression profile (DGEP) data between cultivated soybean and wild type under salt treatment, some GmANKs related to salt/drought response were investigated. Moreover, the expression pattern and subcellular localization of GmANK6 were performed. The results will provide important clues to explore ANK genes expression and function in future studies in soybean.

Global Analysis of WRKY Genes and Their Response to Dehydration and Salt Stress in Soybean.

WRKY proteins are plant specific transcription factors involved in various developmental and physiological processes, especially in biotic and abiotic stress resistance. Although previous studies suggested that WRKY proteins in soybean (Glycine max var. Williams 82) involved in both abiotic and biotic stress responses, the global information of WRKY proteins in the latest version of soybean genome (Wm82.a2v1) and their response to dehydration and salt stress have not been reported. In this study, we identified 176 GmWRKY proteins from soybean Wm82.a2v1 genome. These proteins could be classified into three groups, namely group I (32 proteins), group II (120 proteins), and group III (24 proteins). Our results showed that most GmWRKY genes were located on Chromosome 6, while chromosome 11, 12, and 20 contained the least number of this gene family. More GmWRKY genes were distributed on the ends of chromosomes to compare with other regions. The cis-acting elements analysis suggested that GmWRKY genes were transcriptionally regulated upon dehydration and salt stress. RNA-seq data analysis indicated that three GmWRKY genes responded negatively to dehydration, and 12 genes positively responded to salt stress at 1, 6, and 12 h, respectively. We confirmed by qRT-PCR that the expression of GmWRKY47 and GmWRKY 58 genes was decreased upon dehydration, and the expression of GmWRKY92, 144 and 165 genes was increased under salt treatment.

Potential of thermal image analysis for screening salt stress-tolerant soybean (Glycine max)

Non-destructive high-throughput phenotyping based on phenomics is an emerging technology for assessing the genetic diversity of various traits and screening in breeding programmes. In this study, non-destructive measurements of leaf temperature and chlorophyll fluorescence were conducted to investigate the physiological responses of soybean (Glycine max) to salt stress so as to set up a non-destructive screening method. Two-week-old seedlings of soybean in the V2 stage were treated with 0, 12.5, 25, 50 and 100 mM NaCl to induce salt stress. Three parameters, photosynthesis rate, stomatal conductance and chlorophyll fluorescence, decreased significantly, while soybean leaf temperature increased by exhibiting a positive correlation with NaCl concentration (P< 0.001). Soybean leaf temperature increased significantly at 50 mM NaCl when compared with the untreated control, although no visual symptom was observed. We selected leaf temperature as a major physiological parameter of salt stress as its measurement is much easier, faster and cheaper than that of other physiological parameters. Therefore, leaf temperature can be used for evaluating the responses to salt stress in soybean as a non-destructive and phenomic parameter. The results of this study suggest that non-destructive parameters such as chlorophyll fluorescence and leaf temperature are useful tools for assessing the genetic diversity of soybean with regard to salt stress tolerance and to screen salt stress-tolerant soybean for breeding.

A salt stress-activated mitogen-activated protein kinase in soybean is regulated by phosphatidic acid in early stages of the stress response

Salt stress inhibits plant growth and development and plants activate kinase-dependent survival pathways in response to salt stress. However, the role of soybean mitogenactivated protein kinases (MAPKs) in salt stress response has yet to be characterized. In this study, we found that salt stress activates Glycine max MAP kinase 1 (GMK1), a soybean MAPK. The activity of GMK1 induced with increasing salt concentrations, up to 300 mM NaCl, after 5 min of the treatment and was regulated by post-translational modification. We found that mastoparan, a heteromeric G-protein activator, also activated GMK1, and that n-butanol, a phospholipase D inhibitor, and neomycin, a phospholipase C inhibitor, inhibited its activity. Moreover, GMK1 activity was reduced by suramin, a heteromeric G-protein inhibitor, and by two inhibitors of phosphatidic acid (PA) generation after 5 min of 300 mM NaCl treatment. Endogenous PA levels were highest 5 min after induction of salt stress, and exogenous PA directly activated GMK1. From these data, we propose that salt stress signaling is transduced from heteromeric G-protein to GMK1 via phospholipases in the early stages of the response to salt stress in soybean.

Root Growth Inhibition and Lignification Induced by Salt Stress in Soybean

AbstractSalt stress was evaluated on root growth, enzyme activities (phenylalanine ammonia‐lyase or PAL and soluble plus cell wall‐bound peroxidase or POD), hydrogen peroxide (H2O2) production, total phenolic content and lignin content and composition in soybean (Glycine max L. Merrill) roots. Three‐day‐old seedlings were cultivated in half‐strength Hoagland’s solution (pH 6.0), with or without addition of 50–200 mm of NaCl, into a growth chamber (25 °C, 12/12 h light/dark photoperiod, irradiance of 280 μmol m−2 s−1) for 24 h. In general, root length and fresh and dry weights decreased after NaCl treatment. PAL activity decreased, soluble and cell wall‐bound POD activities increased, and H2O2 content significantly decreased after NaCl exposure. Consequently, total phenolic and lignin contents and p‐hydroxyphenyl (H) and syringyl (S) monomers of lignin increased in NaCl‐treated roots. Altogether, these results suggest that the effects caused by NaCl may be owing to the enhanced lignin production that solidifies the cell wall and restricts root growth.

Molecular cloning and characterization of a novel soybean gene encoding a leucine-zipper-like protein induced to salt stress

To understand molecular responses to salt stress in soybean ( Glycine max [L.] Merr.), we identified 106 salt-inducible soybean genes that expressed differentially at 72 h after 100 mM NaCl treatment using the cDNA-amplified fragment length polymorphism (AFLP) method. The genes were designated as G. max Transcript-Derived Fragments ( GmTDFs). Among these genes, we characterized a soybean gene GmTDF-5 that encoded an unknown protein of 367 amino acids. The GmTDF-5 protein was a putative cytosolic protein with two leucine-zipper motifs at the N-terminal and was calculated as 40.7 kDa. Southern blot analysis indicated that GmTDF-5 presents as an intron-less single gene on soybean genome and possibly distributes narrowly throughout the higher plants. By 100 mM NaCl treatment, the gene expression of GmTDF-5 was induced in the stem and lower-expanded leaf, and the amount of mRNA increased 5.1- and 2.0-fold up to 72 h, respectively. Interestingly, GmTDF-5 expression in the upper-leaf appeared dramatically with 10.0-fold increase at 72 h after the salt stress, but not until 48 h. Hyperosmotic pressure (mannitol treatment) and dehydration also caused the increases similar to NaCl treatment in the levels of GmTDF-5 expression. These results suggest that GmTDF-5 might be a novel cytosolic leucine-zipper-like protein functioning in mature organs of soybean shoot against water-potential changes.

Discrimination of genes expressed in response to the ionic or osmotic effect of salt stress in soybean with cDNA‐AFLP

Abstract‘Ionic effects’ and ‘osmotic effects’ are major components of salt stress in plants. In this study these two parameters were clearly discriminated in soybean (Glycine max (L.) Merr.) using a modified cDNA‐amplified fragment length polymorphism (AFLP) technique. Soybean (cv. Lee) seedlings were exposed to iso‐osmotic treatment consisting of 100 mm NaCl and 12% (w/v) polyethylene glycol 6000 for 24 h. The NaCl treatment fully activated salt tolerance as confirmed by the expression of the inositol‐1‐phosphate synthase gene. Then, gene expression in each sample was examined by cDNA‐AFLP, and 140 differentially expressed cDNA fragments were obtained out of 13 000 amplicons. The percentage of transcripts dependent on ionic (NaCl‐specific) and osmotic effects (common with NaCl and polyethylene glycol) could be evaluated for 44 and 40% of them, respectively. cDNA‐AFLP also revealed the distribution of transcripts in shoots and roots. The ionic effect‐dependent gene expression was more abundant in roots indicating that they showed a greater response to ionic stress than shoots. Several ion transporters, transcription factors and redox enzymes that were specific to the ionic effect may play important roles in the salt tolerance of soybean. The technical advantages of this modified cDNA‐AFLP method are also discussed.

Enhancement of salt tolerance in soybean with NaCl pretreatment

Acclimation response to salt stress in soybean (Glycine max [L.] Merr. cv. Lee) was found in this study. Soybean seedlings were exposed to 0, 34 and 68 mM NaCl for 23 days (pretreatment), thereafter plants were exposed to 0, 68 and 137 mM NaCl until maturity (main treatment). There was no effect of pretreatment on growth, but at 137 mM NaCl, Na+ concentration in leaves of the plants pretreated with 34 mM NaCl was lower than that of plants pretreated with 0 and 68 mM NaCl. Furthermore, the survival rate under 137 mM NaCl improved with the 34 mM NaCl pretreatment. Therefore, it is possible that soybean can acclimate to salt stress by its increased survival rate, without showing any improvement in growth. The regulation of Na+ or Cl− concentration in leaves could be one of the possible factors involved in salt acclimation of soybean.