Overexpression of an adenosine diphosphate-ribosylation factor gene from the halophytic grass Spartina alterniflora confers salinity and drought tolerance in transgenic Arabidopsis (original) (raw)
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Salinity and drought are two very important abiotic stressors that negatively impact the growth and yield of all sensitive crop plants. Genes from halophytes have been shown to be useful to engineer crop plants that can survive under adverse soil and water conditions. The present report establishes, for the first time, the physiological role of a class one ADP ribosylation factor gene (SaARF1) from the halophyte Spartina alterniflora (smooth cordgrass) in imparting salinity and drought stress tolerance when expressed in both monocot (rice) and dicot (Arabidopsis) systems. The Arabidopsis and rice plants overexpressing ARF1 are many-fold more tolerant to salt and drought than wild-type (WT) plants. The transgenics exhibited improved growth and productivity relative to WT through tissue tolerance by maintaining higher relative water content and membrane stability, and higher photosynthetic yield by retaining higher chlorophyll concentration and fluorescence under stress conditions compared to WT. These findings indicated that genes from halophyte resources can be useful to engineer and improve salt and drought stress tolerance in both monocot and dicot plants.
Biochemical and Biophysical Research Communications, 2012
Salinity and drought are the most important environmental constraints limiting crop growth and productivity. Here, we have characterized a gene 'SabNAC' encoding the b subunit of nascent polypeptide associated complex from a halophyte Spartina alterniflora and investigated its role toward abiotic stress regulation. Expression of SabNAC was differentially regulated by abiotic stresses, including salinity, drought, cold, and ABA in leaves and roots of S. alterniflora. Constitutive over-expression of SabNAC in Arabidopsis exhibited normal growth under non-stress conditions but enhanced tolerance to salt and drought stresses. Transgenic SabNAC Arabidopsis retained more chlorophyll, proline, and showed improved ionic homeostasis with less damage under stress conditions compared to WT plants. This is a first report to demonstrate the involvement of bNAC in imparting abiotic stress tolerance which might be due to protection of the newly synthesized polypeptides involved in various stress tolerance mechanisms from abiotic stress induced damage and inhibition of cell death in plant.
Background: SUMO (Small Ubiquitin related Modifier) conjugation is a post translational regulatory process found in all eukaryotes, mediated by SUMO activating enzyme, SUMO conjugating enzyme, and SUMO ligase for the attachment of SUMO to its target protein. Although the mechanism for regulation of SUMO conjugation pathway genes under abiotic stress has been studied to certain extent, the role of SUMO conjugating enzyme in improving abiotic stress tolerance to plant is largely unexplored. Here, we have characterized a SUMO conjugating enzyme gene 'SaSce9' from a halophytic grass Spartina alterniflora and investigated its role in imparting abiotic stress tolerance. Results: SaSce9 gene encodes for a polypeptide of 162 amino acids with a molecular weight of~18 kD and isoelectric point 8.43. Amino acid sequence comparisons of SaSce9 with its orthologs from other plant species showed high degree (~85-93%) of structural conservation among each other. Complementation analysis using yeast SCE mutant, Ubc9, revealed functional conservation of SaSce9 between yeast and S. alterniflora. SaSce9 transcript was inducible by salinity, drought, cold, and exogenously supplied ABA both in leaves and roots of S. alterniflora. Constitutive overexpression of SaSce9 in Arabidopsis through Agrobacterium mediated transformation improved salinity and drought tolerance of Arabidopsis. SaSce9 overexpressing Arabidopsis plants retained more chlorophyll and proline both under salinity and drought stress. SaSce9 transgenic plants accumulated lower levels of reactive oxygen under salinity stress. Expression analysis of stress responsive genes in SaSce9 Arabidopsis plants revealed the increased expression of antioxidant genes, AtSOD and AtCAT, ion antiporter genes, AtNHX1 and AtSOS1, a gene involved in proline biosynthesis, AtP5CS, and a gene involved in ABA dependent signaling pathway, AtRD22.
Plant Molecular Biology, 2010
We describe here the isolation of a novel gene, designated AlSAP, from A. littoralis in a first step to exploit the potential of this halophyte grass as a genetic resource to improve salt and drought tolerance in plants and, particularly, in cereals. The Aeluropus genome contains a single AlSAP gene which has an intron at its 5’UTR. Sequence homology analysis showed that the AlSAP protein is characterized by the presence of two conserved zinc-finger domains A20 and AN1. AlSAP is induced not only by various abiotic stresses such as salt, osmotic, heat and cold but, also by abscisic acid (ABA) and salicylic acid (SA). Tobacco plants expressing the AlSAP gene under the control of the duplicated CaMV35S promoter exhibited an enhanced tolerance to abiotic stresses such as salinity (350 mM NaCl), drought (soil Relative Water Content (RWC) = 25%), heat (55°C for 2.5 h) and freezing (−20°C for 3 h). Moreover, under high salt and drought conditions, the transgenic plants were able to complete their life cycle and to produce viable seeds while the wild-type plants died at the vegetative stage. Measurements of the leaf RWC and of the root and leaf endogenous Na+ and K+ levels in AlSAP transgenic lines compared to wild-type tobacco, showed an evident lower water loss rate and a higher Na+ accumulation in senescent-basal leaves, respectively. Finally, we found that the steady state levels of transcripts of eight stress-related genes were higher in AlSAP transgenic lines than in wild-type tobacco. Taken together, these results show that AlSAP is a potentially useful candidate gene for engineering drought and salt tolerance in cultivated plants.
2021
Ribosomal proteins are highly conserved components of basal cellular organelles, primarily associated with translation of mRNA leading to protein synthesis. Additionally, some of these proteins are known to play critical role in plants RNA metabolism during stress responses, growth, and development. In this study, transgenic Arabidopsis plants expressing a ribosomal protein S27 (hereafter D26) isolated from Solanum tuberosum was subjected to NaCl-induced salinity stress conditions, to evaluate their putative stress resistance. Transgenic plants were exposed to high salinity stress, induced by 200 mM NaCl and physiological and biochemical assays were performed. The D26 transgenic plants demonstrated improved plant height and root length accompanied with higher chlorophyll and carotenoids accumulation compared to wild-type (WT) control plants under stressed conditions. Electrolyte leakage and stomatal conductance, indicators of stress-related tissue damage and plant water status respe...
… : international journal of …, 2010
High salinity is one of the most serious threats to crop production. The primitive red alga, Cyanidioschyzon merolae, inhabits an extreme environment (42°C, pH 2.5, high salt, metal ion). We have utilized the ability of C. merolae cells to adapt to 0.3 M sodium salt, as well as information from its fully sequenced genome, to produce salt-tolerant transgenic higher plants. To reveal the mechanisms of high salt tolerance, we analyzed, by RT-PCR, genes that were expressed at high levels after salt stress (0.3 M NaCl). The C. merolae S-adenosylmethionine synthetase (CmSAMS) gene that codes for an enzyme in the polyamine biosynthesis pathway was expressed at high levels (4 to 5 expression ratio). Our results are in accordance with our previously reported DNA microarray data. The CmSAMS gene codes for a 393-aa protein contain 3 conserved domains at the N-terminal and a semi-conserved domain at the C-terminal. The particle bombardment method revealed that the recombinant CmSAMS-green fluorescent protein was localized in the cytoplasm and the nuclei of the plant cells. To further investigate tolerance to salt stress, we produced, by Agrobacterium-mediated transformation, 4 transgenic Arabidopsis thaliana plant lines expressing CmSAMS. Compared to wild-type plants, the CmSAMS transgenic plants were more tolerant to salt stress, clearly defining a role for the CmSAMS gene in conferring salt-stress tolerance.
PLOS ONE, 2015
The SbASR-1 gene, cloned from a halophyte Salicornia brachiata, encodes a plant-specific hydrophilic and stress responsive protein. The genome of S. brachiata has two paralogs of the SbASR-1 gene (2549 bp), which is comprised of a single intron of 1611 bp, the largest intron of the abscisic acid stress ripening [ASR] gene family yet reported. In silico analysis of the 843-bp putative promoter revealed the presence of ABA, biotic stress, dehydration, phytohormone, salinity, and sugar responsive cis-regulatory motifs. The SbASR-1 protein belongs to Group 7 LEA protein family with different amino acid composition compared to their glycophytic homologs. Bipartite Nuclear Localization Signal (NLS) was found on the Cterminal end of protein and localization study confirmed that SbASR-1 is a nuclear protein. Furthermore, transgenic groundnut (Arachis hypogaea) plants over-expressing the SbASR-1 gene constitutively showed enhanced salinity and drought stress tolerance in the T1 generation. Leaves of transgenic lines exhibited higher chlorophyll and relative water contents and lower electrolyte leakage, malondialdehyde content, proline, sugars, and starch accumulation under stress treatments than wild-type (Wt) plants. Also, lower accumulation of H 2 O 2 and O 2 .radicals was detected in transgenic lines compared to Wt plants under stress conditions. Transcript expression of APX (ascorbate peroxidase) and CAT (catalase) genes were higher in Wt plants, whereas the SOD (superoxide dismutase) transcripts were higher in transgenic lines under stress. Electrophoretic mobility shift assay (EMSA) confirmed that the SbASR-1 protein binds at the consensus sequence (C/G/A)(G/T)CC(C/G)(C/G/A)(A/T). Based on results of the present study, it may be concluded that SbASR-1 enhances the salinity and drought stress tolerance in transgenic groundnut by functioning as a LEA (late embryogenesis abundant) protein and a transcription factor.
Plant Physiology and Biochemistry, 2013
Salinity is one of the most important environmental constraints limiting agricultural productivity. Considering the importance of the accumulation of osmolytes, myo-inositol in particular, in halophytic plant's adaptive response to salinity, an effort was made to overexpress the SaINO1 gene from the grass halophyte Spartina alterniflora encoding myo-inositol 1-phosphate synthase (MIPS) in Arabidopsis thaliana. We demonstrated that SaINO1 is a stress-responsive gene and its constitutive over expression in Arabidopsis provides significantly improved tolerance to salt stress during germination and seedling growth and development. The transgenics retained more chlorophyll and carotenoid by protecting the photosystem II. The low level of stress-induced cellular damage in the transgenics was clearly evident by lower accumulation of proline in comparison to WT. Our results indicated that possible overaccumulation of MIPS enzyme in the cytosol protected the transgenic Arabidopsis plants overexpressing SaINO1 from the toxic effect of Na þ under salt stress by reducing cellular damage and chlorophyll loss.