Salt stress influence on stomatal and hydraulic conductivity, as well as on the level of aquaporins in leaf cells of barley plants, differing in salt tolerance

We studied participation of aquaporins in the regulation of leaf hydraulic conductivity and relationship of hydraulic conductivity with accumulation of ABA and stomatal closure during salt stress. Using the method of immunohistochemical localization we showed that salinity led to greater decline in the level of aquaporins in the region of the vascular leaf bundles of the more salt-tolerant Prairia cultivar, accompanied by a noticeable decrease in hydraulic conductivity of the leaf. In the less salt-tolerant plants of the Mikhailovsky cultivar, significant changes in the level of aquaporins under the influence of salt stress were not found. The degree of decrease in the hydraulic conductivity of the leaf in plants of two cultivars under the influence of salt stress correlated with a decrease in transpiration. Immunohistochemical localization of abscisic acid (ABA) in leaf cells showed that during salt stress this hormone accumulated in leaf mesophyll cells and stomata. The uptake of exogenous hormone from the nutrient solution and its entry into the leaf through the vascular bundles was accompanied by an increase in staining for aquaporins and the hydraulic conductivity of the leaves, which is characteristic of the ABA action. Differences in the localization of exogenous and endogenous hormones were obviously the cause of the opposite directions of changes in hydraulic conductivity: its increase under the influence of an exogenous ABA and a decrease - under the influence of salt stress. ABA concentration assessment in xylem showed the absence of its increase during salt stress, which explains the absence changes of staining for this hormone in the region of the leaf vascular bundles and indicates that accumulation of ABA in a short-term salt stress is not the result of its delivery from the roots, but the result of its synthesis in the shoot itself.

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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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Antioxidative and Metabolic Contribution to Salinity Stress Responses in Two Rapeseed Cultivars during the Early Seedling Stage

Antioxidants ◽

10.3390/antiox10081227 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1227

Author(s):

Ali Mahmoud El-Badri ◽

Maria Batool ◽

Ibrahim A. A. Mohamed ◽

Zongkai Wang ◽

Ahmed Khatab ◽

...

Keyword(s):

Salt Stress ◽

Salinity Stress ◽

Stress Responses ◽

Antioxidant Activities ◽

Tricarboxylic Acid Cycle ◽

Seedling Stage ◽

Plant Performance ◽

Salt Tolerant ◽

Brassica Napus L ◽

Early Seedling

Measuring metabolite patterns and antioxidant ability is vital to understanding the physiological and molecular responses of plants under salinity. A morphological analysis of five rapeseed cultivars showed that Yangyou 9 and Zhongshuang 11 were the most salt-tolerant and -sensitive, respectively. In Yangyou 9, the reactive oxygen species (ROS) level and malondialdehyde (MDA) content were minimized by the activation of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) for scavenging of over-accumulated ROS under salinity stress. Furthermore, Yangyou 9 showed a significantly higher positive correlation with photosynthetic pigments, osmolyte accumulation, and an adjusted Na+/K+ ratio to improve salt tolerance compared to Zhongshuang 11. Out of 332 compounds identified in the metabolic profile, 225 metabolites were filtrated according to p < 0.05, and 47 metabolites responded to salt stress within tolerant and sensitive cultivars during the studied time, whereas 16 and 9 metabolic compounds accumulated during 12 and 24 h, respectively, in Yangyou 9 after being sown in salt treatment, including fatty acids, amino acids, and flavonoids. These metabolites are relevant to metabolic pathways (amino acid, sucrose, flavonoid metabolism, and tricarboxylic acid cycle (TCA), which accumulated as a response to salinity stress. Thus, Yangyou 9, as a tolerant cultivar, showed improved antioxidant enzyme activity and higher metabolite accumulation, which enhances its tolerance against salinity. This work aids in elucidating the essential cellular metabolic changes in response to salt stress in rapeseed cultivars during seed germination. Meanwhile, the identified metabolites can act as biomarkers to characterize plant performance in breeding programs under salt stress. This comprehensive study of the metabolomics and antioxidant activities of Brassica napus L. during the early seedling stage is of great reference value for plant breeders to develop salt-tolerant rapeseed cultivars.

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Morpho- biochemical evaluation of Brassica rapa sub-species for salt tolerance

Genetika ◽

10.2298/gensr1601323j ◽

2016 ◽

Vol 48 (1) ◽

pp. 323-338 ◽

Cited By ~ 3

Author(s):

Sohail Jan ◽

Zabta Shinwari ◽

Malik Rabbani

Keyword(s):

Salt Stress ◽

Chlorophyll A ◽

Brassica Rapa ◽

Research Work ◽

Poor Performance ◽

Dry Weight ◽

Salt Tolerant ◽

Relative Water ◽

Maximum Tolerance ◽

Yellow Type

Salt stress is one of the key abiotic stresses that affect both the qualitative and quantitative characters of many Brassica rapa sub-species by disturbing its normal morphobiochemical processes. Therefore, the present research work was designed to study the effect of different NaCl events (0, 50,100 and 150 mmol) on morphological and biochemical characters and to screen salt tolerant genotypes among brown, yellow and toria types of B. rapa sub-species. The plants were grown in test tubes with addition of four level of NaCl (0, 50,100 and 150 mmol). The effect of salinity on shoot and root length, shoot/ root fresh and dry weight, relative water content (RWC), proline and chlorophyll a, b, a+b contents was recorded after 4 weeks of sowing. The genotype 22861 (brown type) showed excellent morphological and biochemical performance at all stress levels followed by Toria-Sathi and Toria-A respectively as compared to Check variety TS-1. The genotype 26158 (yellow type) gave very poor performance and retard growth. The %RWC values and chlorophyll a, b and a+b contents were decreased several folds with the increase of salt concentration. While, the proline contents was increased with raising of salt stress. The brown and toria types showed maximum tolerance to salt stress at early germination stages as compare to yellows one. The present study will serve as model to develop quick salt tolerant genotypes among different plant sub-species against salt stress.

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Morpho-physiological and gene expression responses of wheat by Aegilops cylindrica amphidiploids to salt stress

10.1101/2020.06.07.139220 ◽

2020 ◽

Author(s):

Razieh Kiani ◽

Ahmad Arzani ◽

S. A. M. Mirmohammady Meibody ◽

Mehdi Rahimmalek ◽

Khadijeh Razavi

Keyword(s):

Salt Stress ◽

Expression Patterns ◽

Ion Homeostasis ◽

Transcript Level ◽

Salt Tolerant ◽

Quantitative Real Time Pcr ◽

Aegilops Cylindrica ◽

Significant Differential Expression ◽

Lower Root ◽

Vacuolar Sequestration

AbstractAegilops cylindrica Host is one of the most salt-tolerant species in the Triticeae tribe. Amphidiploid plants derived from hybridization of ‘Roshan’ × Aegilops cylindrica and ‘Chinese Spring’ × Ae. cylindrica genotypes contrasting in salt tolerance were assessed for their morpho-physiological responses and the expression patterns of two genes related to ion homeostasis under 250 mM NaCl. Results showed that salt stress caused significant declines in both their morphological and phenological traits. Moreover, salt stress reduced not only their chlorophyll content but also their root and shoot K contents and K/Na ratios, while it led to significant enhancements in the remaining traits. Similar to Ae. cylindrica, the amphidiploids subjected to salt stress exhibited significantly higher H2O2 levels, root and shoot K contents, and root and shoot K/Na ratios accompanied by lower root and shoot Na contents and MDA concentrations when compared with the same traits in the wheat parents. Quantitative Real-Time PCR showed significant differential expression patterns of the NHX1 and HKT1;5 genes between the amphidiploids and their parents. The transcript level of HKT1;5 was found to be higher in the roots than in the shoots of both the amphidiploids and Ae. cylindrica while NHX1 exhibited a higher expression in the shoot tissues. The consistency of these data provides compelling support for the hypothesis that active exclusion of Na from the roots and elevated vacuolar sequestration of Na in the leaves might explain the declining Na levels in the shoots and roots of both the amphidiploids and Ae. cylindrica relative to those measured in wheat parents. It is concluded that the hybridized amphiploids are potentially valuable resources for salt improvement in bread wheat through the backcrossing approach.

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Arbuscular mycorrhizal symbioses alleviating salt stress in maize is associated with a decline in root-to-leaf gradient of Na+/K+ ratio

BMC Plant Biology ◽

10.1186/s12870-021-03237-6 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Hao Wang ◽

Tingting An ◽

Di Huang ◽

Runjin Liu ◽

Bingcheng Xu ◽

...

Keyword(s):

Salt Stress ◽

Root System ◽

Chloroplast Ultrastructure ◽

Arbuscular Mycorrhizal ◽

Am Fungi ◽

Mesophyll Cells ◽

Influx Rate ◽

Maize Genotypes ◽

Ionic Imbalance ◽

Underlying Mechanisms

Abstract Background Inoculation of arbuscular mycorrhizal (AM) fungi has the potential to alleviate salt stress in host plants through the mitigation of ionic imbalance. However, inoculation effects vary, and the underlying mechanisms remain unclear. Two maize genotypes (JD52, salt-tolerant with large root system, and FSY1, salt-sensitive with small root system) inoculated with or without AM fungus Funneliformis mosseae were grown in pots containing soil amended with 0 or 100 mM NaCl (incrementally added 32 days after sowing, DAS) in a greenhouse. Plants were assessed 59 DAS for plant growth, tissue Na+ and K+ contents, the expression of plant transporter genes responsible for Na+ and/or K+ uptake, translocation or compartmentation, and chloroplast ultrastructure alterations. Results Under 100 mM NaCl, AM plants of both genotypes grew better with denser root systems than non-AM plants. Relative to non-AM plants, the accumulation of Na+ and K+ was decreased in AM plant shoots but increased in AM roots with a decrease in the shoot: root Na+ ratio particularly in FSY1, accompanied by differential regulation of ion transporter genes (i.e., ZmSOS1, ZmHKT1, and ZmNHX). This induced a relatively higher Na+ efflux (recirculating) rate than K+ in AM shoots while the converse outcoming (higher Na+ influx rate than K+) in AM roots. The higher K+: Na+ ratio in AM shoots contributed to the maintenance of structural and functional integrity of chloroplasts in mesophyll cells. Conclusion AM symbiosis improved maize salt tolerance by accelerating Na+ shoot-to-root translocation rate and mediating Na+/K+ distribution between shoots and roots.

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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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Vigor and alpha-amylase activity in common bean seeds under salt stress conditions

Semina Ciências Agrárias ◽

10.5433/1679-0359.2021v42n6supl2p3633 ◽

2021 ◽

Vol 42 (6supl2) ◽

pp. 3633-3650

Author(s):

Matheus Santin Padilha ◽

◽

Cileide Maria Medeiros Coelho ◽

Natalia Carolina Moraes Ehrhardt-Brocardo ◽

◽

...

Keyword(s):

Salt Stress ◽

Common Bean ◽

Stress Condition ◽

Amylase Activity ◽

Reduction Rate ◽

Stress Conditions ◽

Alpha Amylase ◽

Reserve Mobilization ◽

Relationship Of ◽

The Relationship

Seeds with high vigor have greater capacity for hydrolysis and mobilization of stored reserves, which results in the formation of vigorous seedlings, and this behavior is observed under abiotic stress conditions. This study proposes to investigate the relationship of the enzyme alpha-amylase in lots of common-bean seeds with contrasting vigor, when subjected to the absence and presence of salt stress, aiming to identify the relationship of this enzyme with the vigor of the seed lot under these conditions. Seven common-bean cultivars were used. Physiological quality was determined by germination, vigor index and seedling length. The mobilization of reserves was evaluated under absence and presence of salt stress simulated with a NaCl solution with a concentration of 50 mmol L-1. The analyzed variables regarding reserve mobilization were reserve reduction, reserve reduction rate, seedling dry weight, reserve mobilization rate, starch, starch reduction rate and alpha-amylase activity. Results showed that the stress condition negatively affected all the evaluated variables; however, the cultivars classified as having greater vigor showed better physiological performance under stress. Salt stress in common-bean seeds affects seedling performance and reduces alpha-amylase activity during germination, and high-vigor seed lots exhibited higher enzyme activity in the no-stress condition.

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The full-length transcriptome of Spartina alterniflora reveals the complexity of high salt tolerance in monocotyledonous halophyte

10.1101/680819 ◽

2019 ◽

Cited By ~ 2

Author(s):

Wenbin Ye ◽

Taotao Wang ◽

Wei Wei ◽

Shuaitong Lou ◽

Faxiu Lan ◽

...

Keyword(s):

Gene Expression ◽

Salt Stress ◽

Alternative Splicing ◽

Salt Tolerance ◽

Protein Kinases ◽

Spartina Alterniflora ◽

High Salt ◽

Full Length ◽

Salt Tolerant ◽

High Salt Tolerance

ABSTRACTSpartina alterniflora (Spartina) is the only halophyte in the salt marsh. However, the molecular basis of its high salt tolerance remains elusive. In this study, we used PacBio full-length single molecule long-read sequencing and RNA-seq to elucidate the transcriptome dynamics of high salt tolerance in Spartina by salt-gradient experiments (0, 350, 500 and 800 mM NaCl). We systematically analyzed the gene expression diversity and deciphered possible roles of ion transporters, protein kinases and photosynthesis in salt tolerance. Moreover, the co-expression network analysis revealed several hub genes in salt stress regulatory networks, including protein kinases such as SaOST1, SaCIPK10 and three SaLRRs. Furthermore, high salt stress affected the gene expression of photosynthesis through down-regulation at the transcription level and alternative splicing at the post-transcriptional level. In addition, overexpression of two Spartina salt-tolerant genes SaHSP70-I and SaAF2 in Arabidopsis significantly promoted the salt tolerance of transgenic lines. Finally, we built the SAPacBio website for visualizing the full-length transcriptome sequences, transcription factors, ncRNAs, salt-tolerant genes, and alternative splicing events in Spartina. Overall, this study sheds light on the high salt tolerance mechanisms of monocotyledonous-halophyte and demonstrates the potential of Spartina genes for engineering salt-tolerant plants.

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Beyond the greenhouse: coupling environmental and salt stress response reveals unexpected global transcriptional regulatory networks in Salicornia bigelovii

10.1101/2020.03.17.995720 ◽

2020 ◽

Author(s):

Houda Chelaifa ◽

Manikandan Vinu ◽

Massar Dieng ◽

Youssef Idaghdour ◽

Ayesha Hasan ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Model Systems ◽

Biofuel Production ◽

Salt Tolerant ◽

Plant Model ◽

Tissue Specific ◽

Stress Regulation ◽

Salicornia Bigelovii ◽

Tolerant Plant

AbstractSoil salinity is an increasing threat to global food production systems. As such, there is a need for salt tolerant plant model systems in order to understand salt stress regulation and response. Salicornia bigelovii, a succulent obligatory halophyte, is one of the most salt tolerant plant species in the world. It possesses distinctive characteristics that make it a candidate plant model for studying salt stress regulation and tolerance, showing promise as an economical non-crop species that can be used for saline land remediation and for large-scale biofuel production. However, available S. bigelovii genomic and transcriptomic data are insufficient to reveal its molecular mechanism of salt tolerance. We performed transcriptome analysis of S. bigelovii flowers, roots, seeds and shoots tissues cultivated under desert conditions and irrigated with saline aquaculture effluent. We identified a unique set of tissue specific transcripts present in this non-model crop. A total of 66,943 transcripts (72.63%) were successfully annotated through the GO database with 18,321 transcripts (27.38%) having no matches to known transcripts. Excluding non-plant transcripts, differential expression analysis of 49,914 annotated transcripts revealed differentially expressed transcripts (DETs) between the four tissues and identified shoots and flowers as the most transcriptionally similar tissues relative to roots and seeds. The DETs between above and below ground tissues, with the exclusion of seeds, were primarily involved in osmotic regulation and ion transportation. We identified DETs between shoots and roots implicated in salt tolerance including SbSOS1, SbNHX, SbHKT6 upregulated in shoots relative to roots, while aquaporins (AQPs) were up regulated in roots. We also noted that DETs implicated in osmolyte regulation exhibit a different profile among shoots and roots. Our study provides the first report of a highly upregulated HKT6 from S. bigelovii shoot tissue. Furthermore, we identified two BADH transcripts with divergent sequence and tissue specific expression pattern. Overall, expression of the ion transport transcripts suggests Na+ accumulation in S. bigelovii shoots. Our data led to novel insights into transcriptional regulation across the four tissues and identified a core set of salt stress-related transcripts in S. bigelovii.

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Molecular response of canola to salt stress: insights on tolerance mechanisms

10.7287/peerj.preprints.26716 ◽

2018 ◽

Author(s):

Reza Shokri-Gharelo ◽

Pouya Motie-Noparvar

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Edible Oils ◽

Biodiesel Fuel ◽

Molecular Response ◽

Salt Tolerant ◽

Tolerance Mechanisms ◽

Brassica Napus L ◽

Salt Response ◽

The Many

Canola (Brassica napus L.) is widely cultivated around the world for the production of edible oils and biodiesel fuel. Despite many canola varieties being described as ‘salt-tolerant’, plant yield and growth decline drastically with increasing salinity. Although many studies have resulted in better understanding of the many important salt-response mechanisms that control salt signaling in plants, detoxification of ions, and synthesis of protective metabolites, the engineering of salt-tolerant crops has only progressed slowly. Genetic engineering has been considered as an efficient method for improving the salt tolerance of canola but there are many unknown or little-known aspects regarding canola response to salinity stress at the cellular and molecular level. In order to develop highly salt-tolerant canola, it is essential to improve knowledge of the salt-tolerance mechanisms, especially the key components of the plant salt-response network. In this review, we focus on studies of the molecular response of canola to salinity to unravel the different pieces of the salt response puzzle. The paper includes a comprehensive review of the latest studies, particularly of proteomic and transcriptomic analysis, including the most recently identified canola tolerance components under salt stress, and suggests where researchers should focus future studies.

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