Balancing salinity stress responses in halophytes and non-halophytes: a comparison between Thellungiella and Arabidopsis thaliana

Salinity is one of the major abiotic stress factors that drastically reduces agricultural productivity. In natural environments salinity often occurs together with other stresses such as dehydration, light stress or high temperature. Plants cope with ionic stress, dehydration and osmotic stress caused by high salinity through a variety of mechanisms at different levels involving physiological, biochemical and molecular processes. Halophytic plants exist successfully in stressful saline environments, but most of the terrestrial plants including all crop plants are glycophytes with varying levels of salt tolerance. An array of physiological, structural and biochemical adaptations in halophytes make them suitable models to study the molecular mechanisms associated with salinity tolerance. Comparative analysis of plants that differ in their abilities to tolerate salinity will aid in better understanding the phenomenon of salinity tolerance. The halophyte Thellungiella salsuginea has been used as a model for studying plant salt tolerance. In this review, T. salsuginea and the glycophyte Arabidopsis thaliana are compared with regards to their biochemical, physiological and molecular responses to salinity. In addition recent developments are presented for improvement of salinity tolerance in glycophytic plants using genes from halophytes.

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iTRAQ-Based Comparative Proteomic Analysis Provides Insights into Molecular Mechanisms of Salt Tolerance in Sugar Beet (Beta vulgaris L.)

International Journal of Molecular Sciences ◽

10.3390/ijms19123866 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3866 ◽

Cited By ~ 6

Author(s):

Guo-Qiang Wu ◽

Jin-Long Wang ◽

Rui-Jun Feng ◽

Shan-Jia Li ◽

Chun-Mei Wang

Keyword(s):

Salt Tolerance ◽

Sugar Beet ◽

Beta Vulgaris ◽

Molecular Mechanisms ◽

Stress Factors ◽

Pcr Analysis ◽

Absolute Quantitation ◽

Abiotic Stress Factors ◽

Starting Point ◽

Isobaric Tags

Salinity is one of the major abiotic stress factors that limit plant growth and crop yield worldwide. To understand the molecular mechanisms and screen the key proteins in response of sugar beet (Beta vulgaris L.) to salt, in the present study, the proteomics of roots and shoots in three-week-old sugar beet plants exposed to 50 mM NaCl for 72 h was investigated by isobaric Tags for Relative and Absolute Quantitation (iTRAQ) technology. The results showed that 105 and 30 differentially expressed proteins (DEPs) were identified in roots and shoots of salt-treated plants compared with untreated plants, respectively. There were 46 proteins up-regulated and 59 proteins down-regulated in roots; and 13 up-regulated proteins and 17 down-regulated proteins found in shoots, respectively. These DEPs were mainly involved in carbohydrate metabolism, energy metabolism, lipid metabolism, biosynthesis of secondary metabolites, transcription, translation, protein folding, sorting, and degradation as well as transport. It is worth emphasizing that some novel salt-responsive proteins were identified, such as PFK5, MDH, KAT2, ACAD10, CYP51, F3H, TAL, SRPR, ZOG, V-H+-ATPase, V-H+-PPase, PIPs, TIPs, and tubulin α-2/β-1 chain. qRT-PCR analysis showed that six of the selected proteins, including BvPIP1-4, BvVP and BvVAP in root and BvTAL, BvURO-D1, and BvZOG in shoot, displayed good correlation between the expression levels of protein and mRNA. These novel proteins provide a good starting point for further research into their functions using genetic or other approaches. These findings should significantly improve the understanding of the molecular mechanisms involved in salt tolerance of sugar beet plants.

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Low Mannitol Concentrations in Arabidopsis thaliana Expressing Ectocarpus Genes Improve Salt Tolerance

Plants ◽

10.3390/plants9111508 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1508

Author(s):

Pramod Rathor ◽

Tudor Borza ◽

Yanhui Liu ◽

Yuan Qin ◽

Sophia Stone ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Salt Tolerance ◽

Transgenic Plants ◽

Salinity Stress ◽

Stress Responses ◽

Molecular Mechanisms ◽

Ion Homeostasis ◽

Biotic And Abiotic Stress ◽

Expression Of Genes ◽

Wide Range

Mannitol is abundant in a wide range of organisms, playing important roles in biotic and abiotic stress responses. Nonetheless, mannitol is not produced by a vast majority of plants, including many important crop plants. Mannitol-producing transgenic plants displayed improved tolerance to salt stresses though mannitol production was rather low, in the µM range, compared to mM range found in plants that innately produce mannitol. Little is known about the molecular mechanisms underlying salt tolerance triggered by low concentrations of mannitol. Reported here is the production of mannitol in Arabidopsis thaliana, by expressing two mannitol biosynthesis genes from the brown alga Ectocarpus sp. strain Ec32. To date, no brown algal genes have been successfully expressed in land plants. Expression of mannitol-1-phosphate dehydrogenase and mannitol-1-phosphatase genes was associated with the production of 42.3–52.7 nmol g−1 fresh weight of mannitol, which was sufficient to impart salinity and temperature stress tolerance. Transcriptomics revealed significant differences in the expression of numerous genes, in standard and salinity stress conditions, including genes involved in K+ homeostasis, ROS signaling, plant development, photosynthesis, ABA signaling and secondary metabolism. These results suggest that the improved tolerance to salinity stress observed in transgenic plants producing mannitol in µM range is achieved by the activation of a significant number of genes, many of which are involved in priming and modulating the expression of genes involved in a variety of functions including hormone signaling, osmotic and oxidative stress, and ion homeostasis.

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Jute Responses and Tolerance to Abiotic Stress: Mechanisms and Approaches

Plants ◽

10.3390/plants10081595 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1595

Author(s):

Khussboo Rahman ◽

Naznin Ahmed ◽

Md. Rakib Hossain Raihan ◽

Farzana Nowroz ◽

Faria Jannat ◽

...

Keyword(s):

Abiotic Stress ◽

Stress Responses ◽

Growth Yield ◽

Climatic Conditions ◽

Stress Factors ◽

Growth Physiology ◽

Abiotic Stress Factors ◽

Hot And Humid Climates ◽

Adverse Environmental Conditions ◽

Cold Metal

Jute (Corchorus spp.) belongs to the Malvaceae family, and there are two species of jute, C. capsularis and C. olitorious. It is the second-largest natural bast fiber in the world according to production, which has diverse uses not only as a fiber but also as multiple industrial materials. Because of climate change, plants experience various stressors such as salt, drought, heat, cold, metal/metalloid toxicity, and flooding. Although jute is particularly adapted to grow in hot and humid climates, it is grown under a wide variety of climatic conditions and is relatively tolerant to some environmental adversities. However, abiotic stress often restricts its growth, yield, and quality significantly. Abiotic stress negatively affects the metabolic activities, growth, physiology, and fiber yield of jute. One of the major consequences of abiotic stress on the jute plant is the generation of reactive oxygen species, which lead to oxidative stress that damages its cellular organelles and biomolecules. However, jute’s responses to abiotic stress mainly depend on the plant’s age and type and duration of stress. Therefore, understanding the abiotic stress responses and the tolerance mechanism would help plant biologists and agronomists in developing climate-smart jute varieties and suitable cultivation packages for adverse environmental conditions. In this review, we summarized the best possible recent literature on the plant abiotic stress factors and their influence on jute plants. We described the possible approaches for stress tolerance mechanisms based on the available literature.

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Overexpression of SgGH3.1 from Fine-Stem Stylo (Stylosanthes guianensis var. intermedia) Enhances Chilling and Cold Tolerance in Arabidopsis thaliana

Genes ◽

10.3390/genes12091367 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1367

Author(s):

Ming Jiang ◽

Long-Long Ma ◽

Huai-An Huang ◽

Shan-Wen Ke ◽

Chun-Sheng Gui ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Cold Stress ◽

Stress Responses ◽

Molecular Mechanisms ◽

Transcriptome Profiling ◽

Pasture Legumes ◽

Cold Tolerant ◽

Whole Transcriptome ◽

Altered Sensitivity ◽

Exogenous Iaa

Stylosanthes (stylo) species are commercially significant tropical and subtropical forage and pasture legumes that are vulnerable to chilling and frost. However, little is known about the molecular mechanisms behind stylos’ responses to low temperature stress. Gretchen-Hagen 3 (GH3) proteins have been extensively investigated in many plant species for their roles in auxin homeostasis and abiotic stress responses, but none have been reported in stylos. SgGH3.1, a cold-responsive gene identified in a whole transcriptome profiling study of fine-stem stylo (S. guianensis var. intermedia) was further investigated for its involvement in cold stress tolerance. SgGH3.1 shared a high percentage of identity with 14 leguminous GH3 proteins, ranging from 79% to 93%. Phylogenetic analysis classified SgGH3.1 into Group Ⅱ of GH3 family, which have been proven to involve with auxins conjugation. Expression profiling revealed that SgGH3.1 responded rapidly to cold stress in stylo leaves. Overexpression of SgGH3.1 in Arabidopsis thaliana altered sensitivity to exogenous IAA, up-regulated transcription of AtCBF1-3 genes, activated physiological responses against cold stress, and enhanced chilling and cold tolerances. This is the first report of a GH3 gene in stylos, which not only validated its function in IAA homeostasis and cold responses, but also gave insight into breeding of cold-tolerant stylos.

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Breeding for abiotic stresses for sustainable agriculture

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2007.2179 ◽

2007 ◽

Vol 363 (1492) ◽

pp. 703-716 ◽

Cited By ~ 155

Author(s):

J.R Witcombe ◽

P.A Hollington ◽

C.J Howarth ◽

S Reader ◽

K.A Steele

Keyword(s):

Salinity Tolerance ◽

Abiotic Stresses ◽

Genetic Resistance ◽

Aluminium Toxicity ◽

Stress Factors ◽

Aluminium Tolerance ◽

Abiotic Stress Factors ◽

Genomic Technologies ◽

Component Traits ◽

Good Potential

Using cereal crops as examples, we review the breeding for tolerance to the abiotic stresses of low nitrogen, drought, salinity and aluminium toxicity. All are already important abiotic stress factors that cause large and widespread yield reductions. Drought will increase in importance with climate change, the area of irrigated land that is salinized continues to increase, and the cost of inorganic N is set to rise. There is good potential for directly breeding for adaptation to low N while retaining an ability to respond to high N conditions. Breeding for drought and salinity tolerance have proven to be difficult, and the complex mechanisms of tolerance are reviewed. Marker-assisted selection for component traits of drought in rice and pearl millet and salinity tolerance in wheat has produced some positive results and the pyramiding of stable quantitative trait locuses controlling component traits may provide a solution. New genomic technologies promise to make progress for breeding tolerance to these two stresses through a more fundamental understanding of underlying processes and identification of the genes responsible. In wheat, there is a great potential of breeding genetic resistance for salinity and aluminium tolerance through the contributions of wild relatives.

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The neonicotinoid insecticide thiamethoxam enhances expression of stress-response genes in Zea mays in an environmentally specific pattern

Genome ◽

10.1139/gen-2020-0110 ◽

2020 ◽

Author(s):

Megan Alexandra House ◽

Clarence J Swanton ◽

Lewis N Lukens

Keyword(s):

Cell Growth ◽

Stress Responses ◽

Molecular Mechanisms ◽

Light Stress ◽

Global Gene Expression ◽

Specific Pattern ◽

Plant Responses ◽

Biotic And Abiotic Stress ◽

Neonicotinoid Insecticide ◽

Upregulated Genes

Recent studies indicate that thiamethoxam (TMX), a neonicotinoid insecticide, can affect plant responses to environmental stressors, such as neighboring weeds. The molecular mechanisms behind both stable and environmentally-specific responses to TMX likely involve genes related to defense/stress responses. We investigated the effect of a TMX seed treatment on global gene expression in maize coleoptiles both under normal conditions and under low red to far-red (R/FR) light stress induced by the presence of neighboring plants. The neighboring plant treatment upregulated genes involved in biotic and abiotic stress responses and also affected specific photosynthesis and cell-growth related genes. Low R:FR light may enhance maize resistance to herbivores and pathogens. TMX appears to compromise resistance. The TMX treatment stably repressed many genes that encode proteins involved in biotic stress responses, as well as cell-growth genes. Notably, TMX effects on many genes’ expression were conditional on the environment. In response to low R:FR, plants treated with TMX engage genes in the JA, and other stress-related, response pathways. Neighboring weeds may condition TMX treated plants to become more stress tolerant.

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Exposure to High-Intensity Light Systemically Induces Micro-Transcriptomic Changes in Arabidopsis thaliana Roots

International Journal of Molecular Sciences ◽

10.3390/ijms20205131 ◽

2019 ◽

Vol 20 (20) ◽

pp. 5131

Author(s):

Barczak-Brzyżek Anna ◽

Brzyżek Grzegorz ◽

Koter Marek ◽

Gawroński Piotr ◽

Filipecki Marcin

Keyword(s):

Arabidopsis Thaliana ◽

Stress Responses ◽

High Intensity ◽

Light Stress ◽

Adaptive Responses ◽

Stress Signal ◽

Below Ground ◽

Stress Signals ◽

Transcriptomic Changes ◽

High Intensity Light

In full sunlight, plants often experience a light intensity exceeding their photosynthetic capacity and causing the activation of a set of photoprotective mechanisms. Numerous reports have explained, on the molecular level, how plants cope with light stress locally in photosynthesizing leaves; however, the response of below-ground organs to above-ground perceived light stress is still largely unknown. Since small RNAs are potent integrators of multiple processes including stress responses, here, we focus on changes in the expression of root miRNAs upon high-intensity-light (HL) stress. To achieve this, we used Arabidopsis thaliana plants growing in hydroponic conditions. The expression of several genes that are known as markers of redox changes was examined over time, with the results showing that typical HL stress signals spread to the below-ground organs. Additionally, micro-transcriptomic analysis of systemically stressed roots revealed a relatively limited reaction, with only 17 up-regulated and five down-regulated miRNAs. The differential expression of candidates was confirmed by RT-qPCR. Interestingly, the detected differences in miRNA abundance disappeared when the roots were separated from the shoots before HL treatment. Thus, our results show that the light stress signal is induced in rosettes and travels through the plant to affect root miRNA levels. Although the mechanism of this regulation is unknown, the engagement of miRNA may create a regulatory platform orchestrating adaptive responses to various simultaneous stresses. Consequently, further research on systemically HL-regulated miRNAs and their respective targets has the potential to identify attractive sequences for engineering stress tolerance in plants.

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Qualitative and quantitative variation in the mechanisms of salinity tolerance determined by multivariate assessment of diverse rice (Oryza sativa L.) genotypes

Plant Genetic Resources ◽

10.1017/s1479262115000118 ◽

2015 ◽

Vol 14 (2) ◽

pp. 91-100 ◽

Cited By ~ 3

Author(s):

Mohammad Rashed Hossain ◽

Jeremy Pritchard ◽

Brian V. Ford-Lloyd

Keyword(s):

Salt Tolerance ◽

Salinity Tolerance ◽

Molecular Mechanisms ◽

Oryza Sativa L ◽

Plant Genetic Resources ◽

Screening Method ◽

Physiological Mechanism ◽

Physiological Traits ◽

Ion Balance ◽

Wide Range

Climate change-induced events are causing salinization of many rice-growing areas, requiring the identification of new sources of genetic variation for salt tolerance in plant genetic resources since commonly grown cultivars are sensitive to salt. To identify the level of salt tolerance across a wide range of genotypes, we used a multivariate screening method using multiple growth and physiological traits simultaneously. For this purpose, four indica, two japonica and two wild rice genotypes were grown hydroponically under 40 and 80 mM NaCl stresses; fourteen different growth, qualitative and physiological traits, e.g. plant height, biomass, root and shoot elongation rates, and tissue ion accumulation, were recorded. In general, indica varieties performed better than both japonica and wild species. Our approach identified the existence of qualitatively different mechanisms of salt tolerance across the genotypes. For example, Pokkali, a salt-tolerant indica variety, displayed both ‘Na exclusion’ and ‘ion balance’ mechanisms, whereas PSBRc50 and IR58 showed only ‘Na exclusion’, and the Japonica genotypes Banikat and Nipponbare showed only ‘ion balance’. The results demonstrated that the tolerance is dependent on the level of stress and that this varies between genotypes; Nipponbare is moderately tolerant to 40 mM NaCl but not to 80 mM. We also suggest that the use of multivariate analyses can simplify the complex salinity tolerance picture and can effectively reveal the salinity tolerant genotype from a wide range of germplasm. The results reported here identify different physiological mechanism of tolerance across the genotypes and provide a sound basis for future studies examining their underlying molecular mechanisms.

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Transcriptional Factors Regulate Plant Stress Responses Through Mediating Secondary Metabolism

Genes ◽

10.3390/genes11040346 ◽

2020 ◽

Vol 11 (4) ◽

pp. 346 ◽

Cited By ~ 7

Author(s):

Tehseen Ahmad Meraj ◽

Jingye Fu ◽

Muhammad Ali Raza ◽

Chenying Zhu ◽

Qinqin Shen ◽

...

Keyword(s):

Secondary Metabolism ◽

Stress Responses ◽

Molecular Mechanisms ◽

Plant Stress ◽

Defense Responses ◽

Stress Sensitivity ◽

Transcriptional Factors ◽

Stress Factors ◽

Defense Gene Expression ◽

Signaling Crosstalk

Plants are adapted to sense numerous stress stimuli and mount efficient defense responses by directing intricate signaling pathways. They respond to undesirable circumstances to produce stress-inducible phytochemicals that play indispensable roles in plant immunity. Extensive studies have been made to elucidate the underpinnings of defensive molecular mechanisms in various plant species. Transcriptional factors (TFs) are involved in plant defense regulations through acting as mediators by perceiving stress signals and directing downstream defense gene expression. The cross interactions of TFs and stress signaling crosstalk are decisive in determining accumulation of defense metabolites. Here, we collected the major TFs that are efficient in stress responses through regulating secondary metabolism for the direct cessation of stress factors. We focused on six major TF families including AP2/ERF, WRKY, bHLH, bZIP, MYB, and NAC. This review is the compilation of studies where researches were conducted to explore the roles of TFs in stress responses and the contribution of secondary metabolites in combating stress influences. Modulation of these TFs at transcriptional and post-transcriptional levels can facilitate molecular breeding and genetic improvement of crop plants regarding stress sensitivity and response through production of defensive compounds.

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