Improvement of Salt Tolerance Mechanisms of Barley Cultivated Under Salt Stress Using Azospirillum brasilense

Author(s):  
M. N. A. Omar ◽  
M. E. H. Osman ◽  
W. A. Kasim ◽  
I. A. Abd El-Daim
2018 ◽  
Author(s):  
Reza Shokri-Gharelo ◽  
Pouya Motie-Noparvar

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.


1998 ◽  
Vol 4 (S2) ◽  
pp. 1174-1175
Author(s):  
A.D. Barnabas ◽  
R. Jagels ◽  
W.J. Przybylowicz ◽  
J. Mesjasz-Przybylowicz

Ruppia maritima L. is a submerged halophyte which occurs frequently in estuaries where sodium chloride is the dominant salt. Unlike terrestrial halophytes, R. maritima does not possess any specialised salt-secreting structures such as salt glands. Knowledge of salt tolerance mechanisms in this plant is important to our understanding of its biology. In a previous study it was shown that leaf epidermal cells of R. maritima, which possess transfer cell characteristics, are implicated in salt regulation. In the present investigation, the effect of calcium (Ca) on salt tolerance of leaf epidermal cells was studied since Ca has been found to be an important factor in resistance to salt stress in terrestrial plants.Plants were grown in artificial seawater of high salinity (33%) and at two different Ca concentrations : 400 ppm (high Ca) and 100 ppm (low Ca).


2020 ◽  
Author(s):  
Francisco Gil_Muñoz ◽  
Nicolas Delhomme ◽  
Ana Quiñones ◽  
Maria del Mar Naval ◽  
Maria Badenes ◽  
...  

Abstract Background Drought and salinity are two of the main challenges in agriculture. In many areas, crop production needs solutions to adapt the grown species to the increasing salinity. Research on physiological and molecular responses activated by salinity in plants is needed to elucidate mechanisms of salinity tolerance. Transcriptome profiling (RNA-Seq) is a powerful tool to study the transcriptomic profile of genotypes under stress conditions. In temperate fruit tree species, tree grafting on salinity tolerant rootstocks is a common method to compensate for the cultivar saline sensitivity. Persimmon species have different levels of tolerance to salinity, knowledge of this variability provides the basics for development of salt tolerant rootstocks.Results In this study, we conducted a physiological and transcriptomic profiling of roots and leaves in tolerant and sensitive plants of persimmon rootstock, Diospyros lotus, grown under saline and control conditions. Results from characterization of the physiological responses along with gene expression changes in roots and leaves allowed identifying several salt-tolerance mechanisms related to Ion transport and thermospermine synthesis. Differences were observed in putative H+/ATPases that allow transmembrane ionic transport and Chloride channel protein-like genes. Furthermore, an overexpression of thermospermine synthase found in the roots of tolerant plants may indicate that alterations in root architecture could act as an additional mechanism of response to salt stress. Conclusions Results indicate that D. lotus presents a genetic variability for salt tolerance trait related to the regulation of chloride transport, transmembrane electrochemical potential and thermospermine root synthesis. The study provides knowledge on mechanism of salt stress tolerance in persimmon for further breeding of tolerant persimmon rootstocks.


2021 ◽  
Vol 12 ◽  
Author(s):  
Maryamsadat Vaziriyeganeh ◽  
Shanjida Khan ◽  
Janusz J. Zwiazek

Elevated soil salinity exacerbated by human activities and global climate change poses serious threats to plant survival. Although halophytes provide many important clues concerning salt tolerance in plants, some unanswered questions remain to be addressed, including the processes of water and solute transport regulation. We performed high-throughput RNA-sequencing in roots and metabolome characterizations in roots and leaves of Puccinellia nuttalliana halophytic grass subjected to 0 (control) and 150 mM NaCl. In RNAseq, a total of 31 Gb clean bases generated were de novo assembled into 941,894 transcripts. The PIP2;2 and HKT1;5 transcript levels increased in response to the NaCl treatment implying their roles in water and ion homeostasis. Several transcription factors, including WRKY39, DEK3, HY5, and ABF2, were also overexpressed in response to NaCl. The metabolomic analysis revealed that proline and dopamine significantly increased due to the upregulation of the pathway genes under salt stress, likely contributing to salt tolerance mechanisms. Several phosphatidylcholines significantly increased in roots suggesting that the alterations of membrane lipid composition may be an important strategy in P. nuttalliana for maintaining cellular homeostasis and membrane integrity under salt stress. In leaves, the TCA cycle was enriched suggesting enhanced energy metabolism to cope with salt stress. Other features contributing to the ability of P. nuttalliana to survive under high salinity conditions include salt secretion by the salt glands and enhanced cell wall lignification of the root cells. While most of the reported transcriptomic, metabolomics, and structural alterations may have consequences to water balance maintenance by plants under salinity stress, the key processes that need to be further addressed include the role of the changes in the aquaporin gene expression profiles in the earlier reported enhancement of the aquaporin-mediated root water transport.


2013 ◽  
Vol 40 (9) ◽  
pp. 805 ◽  
Author(s):  
Ricardo Gil ◽  
Monica Boscaiu ◽  
Cristina Lull ◽  
Inmaculada Bautista ◽  
Antonio Lidón ◽  
...  

A general response of plants to high soil salinity relies on the cellular accumulation of osmolytes, which help the plant to maintain osmotic balance under salt stress condition and/or act as ‘osmoprotectants’ with chaperon or reactive oxygen species (ROS) scavenging activities. Yet the ecological relevance of this response for the salt tolerance mechanisms of halophytes in their natural habitats remains largely unknown. In this review, we describe and discuss published data supporting the participation of compatible solutes in those mechanisms, with especial focus on soluble carbohydrates. Evidence for a functional role of carbohydrates in salt tolerance include: (i) relatively high levels of specific sugars and polyols have been detected in many halophytic taxa; (ii) an increase in salt tolerance has often been observed in parallel with increased intracellular levels of particular soluble carbohydrates, in transgenic plants overexpressing the corresponding biosynthetic enzymes; (iii) there are several examples of genes involved in carbohydrate metabolism which are induced under salt stress conditions; (iv) specific sugars or polyols have been shown to accumulate in different halophytes upon controlled salt treatments; and (v) although very few field studies on environmentally induced carbohydrate changes in halophytes exist, in general they also support the involvement of this type of osmolytes in salt stress tolerance mechanisms. We also highlight the complexities of unequivocally attributing carbohydrates a biological role in salt tolerance mechanisms of a given tolerant species. It is proposed that research on halophytes in their natural ecosystems should be intensified, correlating seasonal changes in carbohydrate contents with the degree of environmental stress affecting the plants. This could be an important complement to experiments made under more controlled (but artificial) conditions, such as laboratory set-ups.


2004 ◽  
Vol 59 (11-12) ◽  
pp. 835-842 ◽  
Author(s):  
Balasubramanian Ramani ◽  
Holger Zorn ◽  
Jutta Papenbrock

This study was aimed at understanding the role of sulfolipids in salt tolerance mechanisms of the halophytes Aster tripolium L., Compositae, and Sesuvium portulacastrum L., Aizoaceae, and of the glycophyte Arabidopsis thaliana (L.) Heynh., Brassicaceae. In Aster and Sesuvium the sulfolipid contents increased significantly under salt stress conditions (517 mᴍ or 864 mᴍ). In Arabidopsis, changes in sulfolipid contents were not observed (NaCl up to 100 mᴍ). The fatty acid profile of sulfoquinovosyldiacylglycerol (SQDG) in Aster was modified with increasing NaCl concentrations. LC-MS analyses of sulfolipids from Aster and Sesuvium revealed the presence of 18:3/18:3 and 16:0/18:3 molecules. Obviously, the function of sulfolipids during salt stress differs between halophytic species and between halophytes and glycophytes where sulfolipid accumulation was not observed.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yanira Estrada ◽  
Amanda Fernández-Ojeda ◽  
Belén Morales ◽  
José M. Egea-Fernández ◽  
Francisco B. Flores ◽  
...  

Yield losses due to cultivation in saline soils is a common problem all over the world as most crop plants are glycophytes and, hence, susceptible to salt stress. The use of halophytic crops could be an interesting alternative to cope with this issue. The Amaranthaceae family comprises by far the highest proportion of salt-tolerant halophytic species. Amaranth and quinoa belong to this family, and their seeds used as pseudo-cereal grains have received much attention in recent years because of their exceptional nutritional value. While advances in the knowledge of salt tolerance mechanisms of quinoa have been remarkable in recent years, much less attention was received by amaranth, despite evidences pointing to amaranth as a promising species to be grown under salinity. In order to advance in the understanding of strategies used by amaranth to confront salt stress, we studied the comparative responses of amaranth and quinoa to salinity (100 mM NaCl) at the physiological, anatomical, and molecular levels. Amaranth was able to exhibit salt tolerance throughout its life cycle, since grain production was not affected by the saline conditions applied. The high salt tolerance of amaranth is associated with a low basal stomatal conductance due to a low number of stomata (stomatal density) and degree of stomata aperture (in adaxial surface) of leaves, which contributes to avoid leaf water loss under salt stress in a more efficient way than in quinoa. With respect to Na+ homeostasis, amaranth showed a pattern of Na+ distribution throughout the plant similar to glycophytes, with the highest accumulation found in the roots, followed by the stem and the lowest one detected in the leaves. Contrarily, quinoa exhibited a Na+ includer character with the highest accumulation detected in the shoots. Expression levels of main genes involved in Na+ homeostasis (SOS1, HKT1s, and NHX1) showed different patterns between amaranth and quinoa, with a marked higher basal expression in amaranth roots. These results highlight the important differences in the physiological and molecular responses of amaranth and quinoa when confronted with salinity.


2018 ◽  
Author(s):  
Reza Shokri-Gharelo ◽  
Pouya Motie-Noparvar

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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