Microtubule Dynamics Plays a Vital Role in Plant Adaptation and Tolerance to Salt Stress.
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ABSTRACT:
SUBMITTER: Chun HJ
PROVIDER: S-EPMC8199277 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:Isocitrate lyase (ICL) is a key enzyme in the glyoxylate cycle. In a previous study in rice, the expression of the ICL-encoding gene (OsICL) was highly induced by salt stress and its expression was enhanced in transgenic rice lines overexpressing OsCam1-1, a calmodulin (CaM)-encoding gene. CaM has been implicated in salt tolerance mechanisms in plants; however, the cellular mechanisms mediated by CaM are not clearly understood. In this study, the role of OsICL in plant salt tolerance mechanisms and the possible involvement of CaM were investigated using transgenic plants expressing OsICL or OsCam1-1. RESULTS:OsICL was highly expressed in senesced leaf and significantly induced by salt stress in three OsCam1-1 overexpressing transgenic rice lines as well as in wild type (WT). In WT young leaf, although OsICL expression was not affected by salt stress, all three transgenic lines exhibited highly induced expression levels. In Arabidopsis, salt stress had negative effects on germination and seedling growth of the AtICL knockout mutant (Aticl mutant). To examine the roles of OsICL we generated the following transgenic Arabidopsis lines: the Aticl mutant expressing OsICL driven by the native AtICL promoter, the Aticl mutant overexpressing OsICL driven by the 35SCaMV promoter, and WT overexpressing OsICL driven by the 35SCaMV promoter. Under salt stress, the germination rate and seedling fresh and dry weights of the OsICL-expressing lines were higher than those of the Aticl mutant, and the two lines with the icl mutant background were similar to the WT. The Fv/Fm and temperature of rosette leaves in the OsICL-expressing lines were less affected by salt stress than they were in the Aticl mutant. Finally, glucose and fructose contents of the Aticl mutant under salt stress were highest, whereas those of OsICL-expressing lines were similar to or lower than those of the WT. CONCLUSIONS:OsICL, a salt-responsive gene, was characterized in the transgenic Arabidopsis lines, revealing that OsICL expression could revert the salt sensitivity phenotypes of the Aticl knockout mutant. This work provides novel evidence that supports the role of ICL in plant salt tolerance through the glyoxylate cycle and the possible involvement of OsCam1-1 in regulating its transcription.
| S-EPMC6833277 | biostudies-literature
Project description:Stress granules (SGs), which are formed in the plant cytoplasm under stress conditions, are transient dynamic sites (particles) for mRNA storage. SGs are actively involved in protecting mRNAs from degradation. Oligouridylate binding protein 1b (UBP1b) is a component of SGs. The formation of microscopically visible cytoplasmic foci, referred to as UBP1b SG, was induced by heat treatment in UBP1b-overexpressing Arabidopsis plants (UBP1b-ox). A detailed understanding of the function of UBP1b, however, is still not clear. UBP1b-ox plants displayed increased heat tolerance, relative to control plants, while ubp1b mutants were more sensitive to heat stress than control plants. Microarray analysis identified 117 genes whose expression was heat-inducible and higher in the UBP1b-ox plants. RNA decay analysis was performed using cordycepin, a transcriptional inhibitor. In order to determine if those genes serve as targets of UBP1b, the rate of RNA degradation of a DnaJ heat shock protein and a stress-associated protein (AtSAP3) in UBP1b-ox plants was slower than in control plants; indicating that the mRNAs of these genes were protected within the UBP1b SG granule. Collectively, these data demonstrate that UBP1b plays an integral role in heat stress tolerance in plants.
| S-EPMC4911357 | biostudies-literature
Project description:BackgroundPlasma membrane intrinsic proteins (PIPs) are plant channel proteins involved in water deficit and salinity tolerance. PIPs play a major role in plant cell water balance and responses to salt stress. Although sugarcane is prone to high salt stress, there is no report on PIPs in sugarcane.ResultsIn the present study, eight PIP family genes, termed ScPIP1-1, ScPIP1-2, ScPIP1-3, ScPIP1-4, ScPIP2-1, ScPIP2-2, ScPIP2-4 and ScPIP2-5, were obtained based on the sugarcane transcriptome database. Then, ScPIP2-1 in sugarcane was cloned and characterized. Confocal microscopy observation indicated that ScPIP2-1 was located in the plasma membrane and cytoplasm. A yeast two-hybridization experiment revealed that ScPIP2-1 does not have transcriptional activity. Real time quantitative PCR (RT-qPCR) analysis showed that ScPIP2-1 was mainly expressed in the leaf, root and bud, and its expression levels in both below- and aboveground tissues of ROC22 were up-regulated by abscisic acid (ABA), polyethylene glycol (PEG) 6000 and sodium chloride (NaCl) stresses. The chlorophyll content and ion leakage measurement suggested that ScPIP2-1 played a significant role in salt stress resistance in Nicotiana benthamiana through the transient expression test. Overexpression of ScPIP2-1 in Arabidopsis thaliana proved that this gene enhanced the salt tolerance of transgenic plants at the phenotypic (healthier state, more stable relative water content and longer root length), physiologic (more stable ion leakage, lower malondialdehyde content, higher proline content and superoxide dismutase activity) and molecular levels (higher expression levels of AtKIN2, AtP5CS1, AtP5CS2, AtDREB2, AtRD29A, AtNHX1, AtSOS1 and AtHKT1 genes and a lower expression level of the AtTRX5 gene).ConclusionsThis study revealed that the ScPIP2-1-mediated osmotic stress signaling cascade played a positive role in plant response to salt stress.
| S-EPMC8667355 | biostudies-literature
Project description:Late embryogenesis abundant (LEA) proteins are involved in tolerance to drought, cold and high salinity in many different organisms. In this report, a LEA protein producing full-length gene OsLEA3-2 was identified in rice (Oryza sativa) using the Rapid Amplification of cDNA Ends (RACE) method. OsLEA3-2 was found to be only expressed in the embryo and can be induced by abiotic stresses. The coding protein localizes to the nucleus and overexpression of OsLEA3-2 in yeast improved growth performance compared with control under salt- and osmotic-stress conditions. OsLEA3-2 was also inserted into pHB vector and overexpressed in Arabidopsis and rice. The transgenic Arabidopsis seedlings showed better growth on MS media supplemented with 150 mM mannitol or 100 mM NaCl as compared with wild type plants. The transgenic rice also showed significantly stronger growth performance than control under salinity or osmotic stress conditions and were able to recover after 20 days of drought stress. In vitro analysis showed that OsLEA3-2 was able to protect LDH from aggregation on freezing and inactivation on desiccation. These results indicated that OsLEA3-2 plays an important role in tolerance to abiotic stresses.
| S-EPMC3443202 | biostudies-literature
Project description:BackgroundThe C-repeat-binding factors/DRE-binding factors (CBF/DREBs) comprise a key transcription factor family involved in plant stress tolerance. Yet, there is limited information about switchgrass DREB genes and their functional roles.ResultsIn this study, four cold-inducible PvDREB1s were identified from switchgrass (Panicum virgatum), among which PvDREB1C was the one responded to cold stress later than the other three PvDREB1s. Yet, ectopic overexpression of PvDREB1C led to significantly compromised, instead of improved cold tolerance in transgenic tobacco. On the other hand, PvDREB1C was transcriptionally down-regulated in response to salt stress, but overexpression of PvDREB1C improved plant salt tolerance in transgenic tobacco. The improved salt tolerance was associated with increased K+/Na+ ratio and Ca2+ content, higher cellular osmotic potential, and activation of stress-related functional genes in the leaves of transgenic plants under salt stress.ConclusionsThe current results implied that PvDREB1C played opposite roles in plant cold and salt tolerance. Although DREB1s were known as positive stress regulators, particular attentions shall be paid to their potential negative regulatory role(s).
| S-EPMC5655823 | biostudies-literature
Project description:BackgroundABC1K (Activity of BC1 complex Kinase) is an evolutionarily primitive atypical kinase family widely distributed among prokaryotes and eukaryotes. The ABC1K protein kinases in Arabidopsis are predicted to localize either to the mitochondria or chloroplasts, in which plastid-located ABC1K proteins are involved in the response against photo-oxidative stress and cadmium-induced oxidative stress.ResultsHere, we report that the mitochondria-localized ABC1K10a functions in plant salt stress tolerance by regulating reactive oxygen species (ROS). Our results show that the ABC1K10a expression is induced by salt stress, and the mutations in this gene result in overaccumulation of ROS and hypersensitivity to salt stress. Exogenous application of the ROS-scavenger GSH significantly represses ROS accumulation and rescues the salt hypersensitive phenotype of abc1k10a. ROS overaccumulation in abc1k10a mutants under salt stress is likely due to the defect in mitochondria electron transport chain. Furthermore, defects of several other mitochondria-localized ABC1K genes also result in salt hypersensitivity.ConclusionsTaken together, our results reveal that the mitochondria-located ABC1K10a regulates mitochondrial ROS production and is a positive regulator of salt tolerance in Arabidopsis.
| S-EPMC7288548 | biostudies-literature
Project description:Applying proteomics, we tested the physiological responses of the euryhaline seagrass Cymodocea nodosa to deliberate manipulation of salinity in a mesocosm system. Plants were subjected to a chronic hypersaline condition (43 psu) to compare protein expression and plant photochemistry responses after 15 and 30 days of exposure with those of plants cultured under normal/ambient saline conditions (37 psu). Results showed a general decline in the expression level of leaf proteins in hypersaline stressed plants, with more intense reductions after long-lasting exposure. Specifically, the carbon-fixing enzyme RuBisCo displayed a lower accumulation level in stressed plants relative to controls. In contrast, the key enzymes involved in the regulation of glycolysis, cytosolic glyceraldehyde-3-phosphate dehydrogenase, enolase 2 and triose-phosphate isomerase, showed significantly higher accumulation levels. These responses suggested a shift in carbon metabolism in stressed plants. Hypersaline stress also induced a significant alteration of the photosynthetic physiology of C. nodosa by means of a down-regulation in structural proteins and enzymes of both PSII and PSI. However we found an over-expression of the cytochrome b559 alpha subunit of the PSII initial complex, which is a receptor for the PSII core proteins involved in biogenesis or repair processes and therefore potentially involved in the absence of effects at the photochemical level of stressed plants. As expected hypersalinity also affects vacuolar metabolism by increasing the leaf cell turgor pressure and enhancing the up-take of Na(+) by over-accumulating the tonoplast specific intrinsic protein pyrophosphate-energized inorganic pyrophosphatase (H(+)-PPase) coupled to the Na(+)/H(+)-antiporter. The modulation of carbon metabolism and the enhancement of vacuole capacity in Na(+) sequestration and osmolarity changes are discussed in relation to salt tolerance of C. nodosa.
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Project description:Sucrose non-fermenting 1-related protein kinases (SnRKs) are important for plant growth and stress responses. This family has three clades: SnRK1, SnRK2 and SnRK3. Although plant SnRKs are thought to be activated by upstream kinases, the overall mechanism remains obscure. Geminivirus Rep-Interacting Kinase (GRIK)1 and GRIK2 phosphorylate SnRK1s, which are involved in sugar/energy sensing, and the grik1-1 grik2-1 double mutant shows growth retardation under regular growth conditions. In this study, we established another Arabidopsis mutant line harbouring a different allele of gene GRIK1 (grik1-2 grik2-1) that grows similarly to the wild-type, enabling us to evaluate the function of GRIKs under stress conditions. In the grik1-2 grik2-1 double mutant, phosphorylation of SnRK1.1 was reduced, but not eliminated, suggesting that the grik1-2 mutation is a weak allele. In addition to high sensitivity to glucose, the grik1-2 grik2-1 mutant was sensitive to high salt, indicating that GRIKs are also involved in salinity signalling pathways. Salt Overly Sensitive (SOS)2, a member of the SnRK3 subfamily, is a critical mediator of the response to salinity. GRIK1 phosphorylated SOS2 in vitro, resulting in elevated kinase activity of SOS2. The salt tolerance of sos2 was restored to normal levels by wild-type SOS2, but not by a mutated form of SOS2 lacking the T168 residue phosphorylated by GRIK1. Activation of SOS2 by GRIK1 was also demonstrated in a reconstituted system in yeast. Our results indicate that GRIKs phosphorylate and activate SnRK1 and other members of the SnRK3 family, and that they play important roles in multiple signalling pathways in vivo.
| S-EPMC5814739 | biostudies-literature
Project description:Soil salinity is one of the major abiotic stresses restricting the use of land for agriculture because it limits the growth and development of most crop plants. Improving productivity under these physiologically stressful conditions is a major scientific challenge because salinity has different effects at different developmental stages in different crops. When supplied exogenously, proline has improved salt stress tolerance in various plant species. Under high-salt conditions, proline application enhances plant growth with increases in seed germination, biomass, photosynthesis, gas exchange, and grain yield. These positive effects are mainly driven by better nutrient acquisition, water uptake, and biological nitrogen fixation. Exogenous proline also alleviates salt stress by improving antioxidant activities and reducing Na+ and Cl- uptake and translocation while enhancing K+ assimilation by plants. However, which of these mechanisms operate at any one time varies according to the proline concentration, how it is applied, the plant species, and the specific stress conditions as well as the developmental stage. To position salt stress tolerance studies in the context of a crop plant growing in the field, here we discuss the beneficial effects of exogenous proline on plants exposed to salt stress through well-known and more recently described examples in more than twenty crop species in order to appreciate both the diversity and commonality of the responses. Proposed mechanisms by which exogenous proline mitigates the detrimental effects of salt stress during crop plant growth are thus highlighted and critically assessed.
| S-EPMC7390974 | biostudies-literature
Project description:Chloroplasts play crucial roles in biotic and abiotic stress responses, regulated by nuclear gene expression through changes in the cellular redox state. Despite lacking the N-terminal chloroplast transit peptide (cTP), nonexpressor of pathogenesis-related genes 1 (NPR1), a redox-sensitive transcriptional coactivator was consistently found in the tobacco chloroplasts. Under salt stress and after exogenous application of H2O2 or aminocyclopropane-1-carboxylic acid, an ethylene precursor, transgenic tobacco plants expressing green fluorescent protein (GFP)-tagged NPR1 (NPR1-GFP) showed significant accumulation of monomeric nuclear NPR1, irrespective of the presence of cTP. Immunoblotting and fluorescence image analyses indicated that NPR1-GFP, with and without cTP, had similar molecular weights, suggesting that the chloroplast-targeted NPR1-GFP is likely translocated from the chloroplasts to the nucleus after processing in the stroma. Translation in the chloroplast is essential for nuclear NPR1 accumulation and stress-related expression of nuclear genes. An overexpression of chloroplast-targeted NPR1 enhanced stress tolerance and photosynthetic capacity. In addition, compared to the wild-type lines, several genes encoding retrograde signaling-related proteins were severely impaired in the Arabidopsis npr1-1 mutant, but were enhanced in NPR1 overexpression (NPR1-Ox) transgenic tobacco line. Taken together, chloroplast NPR1 acts as a retrograding signal that enhances the adaptability of plants to adverse environments.
| S-EPMC10215103 | biostudies-literature