Overexpression of alfalfa mitochondrial HSP23 in prokaryotic and eukaryotic model systems confers enhanced tolerance to salinity and arsenic stress.
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ABSTRACT:
SUBMITTER: Lee KW
PROVIDER: S-EPMC3235403 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Salinity stress is one of the major factors negatively affecting growth and productivity in living organisms including plants and bacteria resulting in significant losses worldwide. Therefore, it would be fruitful to develop salinity stress tolerant useful species and also to understand the mechanism of stress tolerance. The pea DNA helicase 45 (PDH45) is a DNA and RNA helicase, homologous to eukaryotic translation initiation factor 4A (eIF-4A) and is involved in various processes including protein synthesis, maintaining the basic activities of the cell, upregulation of topoisomerase I activity and salinity stress tolerance in plant, but its role in salinity stress tolerance in bacteria has not heretofore been studied. This study provides an evidence for a novel function of the PDH45 gene in high salinity (NaCl) stress tolerance in bacteria (Eschericia coli, BL21 cells) also. Furthermore, it has been shown that the functionally active PDH45 gene is required to show the stress tolerance in bacteria because the single mutants (E183G or R363Q) and the double mutant (E183G + R363Q) of the gene could not confer the same function. The response was specific to Na+ ions as the bacteria could not grow in presence of LiCl. This study suggests that the cellular response to high salinity stress across prokaryotes and plant kingdom is conserved and also helps in our better understanding of mechanism of stress tolerance in bacteria and plants. It could also be very useful in developing high salinity stress tolerant useful bacteria of agronomic importance. Overall, this study provides an evidence for a novel function of the PDH45 gene in high salinity stress tolerance in bacteria.
| S-EPMC3258049 | biostudies-literature
Project description:Salt tolerance is an important trait that is required to overcome salinity-induced reduction in plant productivity. We have reported previously the isolation of a pea DNA helicase 45 (PDH45) that exhibits striking homology with the eukaryotic translation initiation factor eIF-4A. Here, we report that PDH45 mRNA is induced in pea seedlings in response to high salt, and its overexpression driven by a constitutive cauliflower mosaic virus-(35)S promoter in tobacco plants confers salinity tolerance, thus suggesting a previously undescribed pathway for manipulating stress tolerance in crop plants. The T(0) transgenic plants showed high levels of PDH45 protein in normal and stress conditions, as compared with WT plants. The T(0) transgenics also showed tolerance to high salinity as tested by a leaf disk senescence assay. The T(1) transgenics were able to grow to maturity and set normal viable seeds under continuous salinity stress without any reduction in plant yield in terms of seed weight. Measurement of Na(+) ions in different parts of the plant showed higher accumulation in the old leaves and negligible accumulation in seeds of T(1) transgenic lines as compared with the WT plants. The possible mechanism of salinity tolerance is discussed. Overexpression of PDH45 provides a possible example of the exploitation of DNA/RNA unwinding pathways for engineering salinity tolerance without affecting yield in crop plants.
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Project description:Expansins are key regulators of cell-wall extension and are also involved in the abiotic stress response. In this study, we evaluated the function of OsEXPA7 involved in salt stress tolerance. Phenotypic analysis showed that OsEXPA7 overexpression remarkably enhanced tolerance to salt stress. OsEXPA7 was highly expressed in the shoot apical meristem, root, and the leaf sheath. Promoter activity of OsEXPA7:GUS was mainly observed in vascular tissues of roots and leaves. Morphological analysis revealed structural alterations in the root and leaf vasculature of OsEXPA7 overexpressing (OX) lines. OsEXPA7 overexpression resulted in decreased sodium ion (Na+) and accumulated potassium ion (K+) in the leaves and roots. Under salt stress, higher antioxidant activity was also observed in the OsEXPA7-OX lines, as indicated by lower reactive oxygen species (ROS) accumulation and increased antioxidant activity, when compared with the wild-type (WT) plants. In addition, transcriptional analysis using RNA-seq and RT-PCR revealed that genes involved in cation exchange, auxin signaling, cell-wall modification, and transcription were differentially expressed between the OX and WT lines. Notably, salt overly sensitive 1, which is a sodium transporter, was highly upregulated in the OX lines. These results suggest that OsEXPA7 plays an important role in increasing salt stress tolerance by coordinating sodium transport, ROS scavenging, and cell-wall loosening.
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Project description:Alkaline stress severely limits plant growth and yield worldwide. NF-YC transcription factors (TFs) respond to abiotic stress by activating gene expression. However, the biological function of NF-YC TFs in alfalfa (Medicago sativa L.) is not clear. In our study, an NF-YC2 gene was identified and transgenic plants were obtained by constructing overexpression vector and cotyledon node transformation system in alfalfa. The open reading frame of MsNF-YC2 is 879 bp with 32.4 kDa molecular mass. MsNF-YC2 showed tissue expression specificity and was induced by a variety of abiotic stresses including drought, salt, and alkali stress in alfalfa. Under alkali stress treatment, transgenic plants exhibited higher levels of antioxidant enzyme activities and proline (Pro), correlating with a lower levels of hydrogen peroxide (H2O2), superoxide anion (O2 -) compared with wild-type (WT) plants. Transcriptomic results showed that overexpression of MsNF-YC2 regulated the expression of phytohormone signal transduction and photosynthesis-related genes under normal and alkaline stress treatments. These results suggest that the MsNF-YC2 gene plays crucial role enhance alkali adaptation abilities in alfalfa.
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Project description:Microbes play a crucial role in the arsenic biogeochemical cycle through specific metabolic pathways to adapt to arsenic toxicity. However, the different arsenic-detoxification strategies between prokaryotic and eukaryotic microbes are poorly understood. This hampers our comprehension of how microbe-arsenic interactions drive the arsenic cycle and the development of microbial methods for remediation. In this study, we utilized conserved protein domains from 16 arsenic biotransformation genes (ABGs) to search for homologous proteins in 670 microbial genomes. Prokaryotes exhibited a wider species distribution of arsenic reduction- and arsenic efflux-related genes than fungi, whereas arsenic oxidation-related genes were more prevalent in fungi than in prokaryotes. This was supported by significantly higher acr3 (arsenite efflux permease) expression in bacteria (upregulated 3.72-fold) than in fungi (upregulated 1.54-fold) and higher aoxA (arsenite oxidase) expression in fungi (upregulated 5.11-fold) than in bacteria (upregulated 2.05-fold) under arsenite stress. The average values of nonsynonymous substitutions per nonsynonymous site to synonymous substitutions per synonymous site (dN/dS) of homologous ABGs were higher in archaea (0.098) and bacteria (0.124) than in fungi (0.051). Significant negative correlations between the dN/dS of ABGs and species distribution breadth and gene expression levels in archaea, bacteria, and fungi indicated that microbes establish the distinct strength of purifying selection for homologous ABGs. These differences contribute to the distinct arsenic metabolism pathways in prokaryotic and eukaryotic microbes. These observations facilitate a significant shift from studying individual or several ABGs to characterizing the comprehensive microbial strategies of arsenic detoxification.
| S-EPMC11370035 | biostudies-literature
Project description:The WRKY transcription factors play an important role in the regulation of transcriptional reprogramming associated with plant abiotic stress responses. In this study, the WRKY transcription factor MsWRKY11, containing the plant-specific WRKY zinc finger DNA-binding motif, was isolated from alfalfa. The MsWRKY11 gene was detected in all plant tissues (root, stem, leaf, flower, and fruit), with high expression in root and leaf tissues. MsWRKY11 was upregulated in response to a variety of abiotic stresses, including salinity, alkalinity, cold, abscisic acid, and drought. Overexpression of MsWRKY11 in soybean enhanced the salt tolerance at the seedling stage. Transgenic soybean had a better salt-tolerant phenotype, and the hypocotyls were significantly longer than those of wild-type seeds after salt treatment. Furthermore, MsWRKY11 overexpression increased the contents of chlorophyll, proline, soluble sugar, superoxide dismutase, and catalase, but reduced the relative electrical conductivity and the contents of malonaldehyde, H2O2, and O2-. Plant height, pods per plant, seeds per plant, and 100-seed weight of transgenic MsWRKY11 soybean were higher than those of wild-type soybean, especially OX2. Results of the salt experiment showed that MsWRKY11 is involved in salt stress responses, and its overexpression improves salt tolerance in soybean.
| S-EPMC5821330 | biostudies-literature
Project description:Expanding the genetic toolbox for prokaryotic synthetic biology is a promising strategy for enhancing the dynamic range of gene expression and enabling new engineered applications for research and biomedicine. Here, we reverse the current trend of moving genetic parts from prokaryotes to eukaryotes and demonstrate that the activating eukaryotic transcription factor QF and its corresponding DNA-binding sequence can be moved to E. coli to introduce transcriptional activation, in addition to tight off states. We further demonstrate that the QF transcription factor can be used in genetic devices that respond to low input levels with robust and sustained output signals. Collectively, we show that eukaryotic gene regulator elements are functional in prokaryotes and establish a versatile and broadly applicable approach for constructing genetic circuits with complex functions. These genetic tools hold the potential to improve biotechnology applications for medical science and research.
| S-EPMC8257575 | biostudies-literature
Project description:BackgroundHeat shock proteins (HSPs) are found extensively in Eukaryotes and are involved in stress tolerance. However, their functions in herbaceous peony (Paeonia lactiflora Pall.) under high temperature stress are poorly characterized.ResultsIn this study, the genomic sequence of P. lactiflora HSP70, designated PlHSP70, was isolated. Its full-length was 3635 bp, and it contained a large 1440-bp intron. The encoded protein with a molecular weight of 71 kDa was localized in the cytoplasm of the cell. PlHSP70 transcription was detected in P. lactiflora and increased with the treatment of high temperature stress. The constitutive overexpression of PlHSP70 in Arabidopsis thaliana obviously conferred tolerance to high temperature stress by affecting different physiological and biochemical indices. Transgenic A. thaliana plants exhibited higher chlorophyll fluorescence values than the wild-type (WT) when exposed to high temperature stress. The accumulation of hydrogen peroxide (H2O2), superoxide anion free radical (O2·-) and relative electric conductivity (REC) were significantly lower in the transgenic A. thaliana plants compared to the WT. In addition, more intact cell membranes, chloroplasts and starch grains, and fewer plastoglobuli were found in the PlHSP70-overexpressing transgenic lines than in the WT.ConclusionsAll of these results indicated that PlHSP70 possessed the ability to improve the tolerance to high temperature in transgenic A. thaliana, which could provide a theoretical basis to improve high temperature tolerance of P. lactiflora by future genetic manipulation.
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Project description:Soil salinity is a major environmental stress limiting plant growth and productivity. We have reported previously the isolation of an Apocynum venetum DEAD-box helicase 1 (AvDH1) that is expressed in response to salt exposure. Here, we report that the overexpression of AvDH1 driven by a constitutive cauliflower mosaic virus-35S promoter in cotton plants confers salinity tolerance. Southern and Northern blotting analyses showed that the AvDH1 gene was integrated into the cotton genome and expressed. In this study, the growth of transgenic cotton expressing AvDH1 was evaluated under saline conditions in a growth chamber and in a saline field trial. Transgenic cotton overexpressing AvDH1 was much more resistant to salt than the wild-type plants when grown in a growth chamber. The lower membrane ion leakage, along with increased activity of superoxide dismutase, in AvDH1 transgenic lines suggested that these characteristics may prevent membrane damage, which increases plant survival rates. In a saline field, the transgenic cotton lines expressing AvDH1 showed increased boll numbers, boll weights and seed cotton yields compared with wild-type plants, especially at high soil salinity levels. This study indicates that transgenic cotton expressing AvDH1 is a promising option for increasing crop productivity in saline fields.
| S-EPMC4705273 | biostudies-literature
Project description:Soil salinization is a global environmental issue and a significant abiotic stress that threatens crop production. Root-associated rhizosphere microbiota play a pivotal role in enhancing plant tolerance to abiotic stresses. However, limited information is available concerning the specific variations in rhizosphere microbiota driven by different plant genotypes (varieties) in response to varying levels of salinity stress. In this study, we compared the growth performance of three alfalfa varieties with varying salt tolerance levels in soils with different degrees of salinization. High-throughput 16S rRNA and ITS sequencing were employed to analyze the rhizosphere microbial communities. Undoubtedly, the increasing salinity significantly inhibited alfalfa growth and reduced rhizosphere microbial diversity. However, intriguingly, salt-tolerant varieties exhibited relatively lower susceptibility to salinity, maintaining more stable rhizosphere bacterial community structure, whereas the reverse was observed for salt-sensitive varieties. Bacillus emerged as the dominant species in alfalfa's adaptation to salinity stress, constituting 21.20% of the shared bacterial genera among the three varieties. The higher abundance of Bacillus, Ensifer, and Pseudomonas in the rhizosphere of salt-tolerant alfalfa varieties is crucial in determining their elevated salt tolerance. As salinity levels increased, salt-sensitive varieties gradually accumulated a substantial population of pathogenic fungi, such as Fusarium and Rhizoctonia. Furthermore, rhizosphere bacteria of salt-tolerant varieties exhibited increased activity in various metabolic pathways, including biosynthesis of secondary metabolites, carbon metabolism, and biosynthesis of amino acids. It is suggested that salt-tolerant alfalfa varieties can provide more carbon sources to the rhizosphere, enriching more effective plant growth-promoting bacteria (PGPB) such as Pseudomonas to mitigate salinity stress. In conclusion, our results highlight the variety-mediated enrichment of rhizosphere microbiota in response to salinity stress, confirming that the high-abundance enrichment of specific dominant rhizosphere microbes and their vital roles play a significant role in conferring high salt adaptability to these varieties.
| S-EPMC10766110 | biostudies-literature