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The Translation Initiation Factor 1A ( TheIF1A ) from Tamarix hispida Is Regulated by a Dof Transcription Factor and Increased Abiotic Stress Tolerance

View Article: PubMed Central - PubMed

ABSTRACT

Eukaryotic translation initiation factor 1A (eIF1A) functions as an mRNA scanner and AUG initiation codon locator. However, few studies have clarified the role of eIF1A in abiotic stress. In this study, we cloned eIF1A (TheIF1A) from Tamarix hispida and found its expression to be induced by NaCl and polyethylene glycol (PEG) in roots, stems, and leaves. Compared to control, TheIF1A root expression was increased 187.63-fold when exposed to NaCl for 6 h, suggesting a potential abiotic stress response for this gene. Furthermore, transgenic tobacco plants overexpressing TheIF1A exhibited enhanced seed germination and a higher total chlorophyll content under salt and mannitol stresses. Increased superoxide dismutase, peroxidase, glutathione transferase and glutathione peroxidase activities, as well as decreased electrolyte leakage rates and malondialdehyde contents, were observed in TheIF1A-transgenic tobacco and T. hispida seedlings under salt and mannitol stresses. Histochemical staining suggested that TheIF1A improves reactive oxygen species (ROS) scavenging in plants. Moreover, TheIF1A may regulate expression of stress-related genes, including TOBLTP, GST, MnSOD, NtMPK9, poxN1, and CDPK15. Moreover, a 1352-bp promoter fragment of TheIF1A was isolated, and cis-elements were identified. Yeast one-hybrid assays showed that ThDof can specifically bind to the Dof motif present in the promoter. In addition, ThDof showed expression patterns similar to those of TheIF1A under NaCl and PEG stresses. These findings suggest the potential mechanism and physiological roles of TheIF1A. ThDof may be an upstream regulator of TheIF1A, and TheIF1A may function as a stress response regulator to improve plant salt and osmotic stress tolerance via regulation of associated enzymes and ROS scavenging, thereby reducing cell damage under stress conditions.

No MeSH data available.


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Reactive oxygen species (ROS) levels and cell death in TheIF1A transgenic tobacco plants and WT under different stress conditions. All experiments were repeated at least three times, and approximately 15 leaves collected from multiple 28-days-old seedlings were inspected in each experiment. (A) DAB staining indicates accumulation of H2O2 in leaves of WT and transgenic plants subjected to 1, 2, or 3 h of salt or mannitol stress. (B) NBT staining of O2- accumulation in leaves according to DAB staining. (C) Evans blue staining. (D) Representative microscopy images of ROS production in intact guard cells, as indicated by the fluorescent dye DCF. Epidermal peels were loaded with H2DCF-DA for 10 min after incubation in fixing buffer for 2 h. (E) ROS production in the root, as indicated by the fluorescent dye DCF. Main roots detached from control, NaCl and mannitol stress (1 h) plants were incubated in incubation buffer for 2 h at room temperature and subsequently stained with 5 μM H2DCF-DA for 10 min. (F) The total H2O2 content according to the staining (A–F). ∗indicates significant differences between transgenic lines and WT (p < 0.05).
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Figure 5: Reactive oxygen species (ROS) levels and cell death in TheIF1A transgenic tobacco plants and WT under different stress conditions. All experiments were repeated at least three times, and approximately 15 leaves collected from multiple 28-days-old seedlings were inspected in each experiment. (A) DAB staining indicates accumulation of H2O2 in leaves of WT and transgenic plants subjected to 1, 2, or 3 h of salt or mannitol stress. (B) NBT staining of O2- accumulation in leaves according to DAB staining. (C) Evans blue staining. (D) Representative microscopy images of ROS production in intact guard cells, as indicated by the fluorescent dye DCF. Epidermal peels were loaded with H2DCF-DA for 10 min after incubation in fixing buffer for 2 h. (E) ROS production in the root, as indicated by the fluorescent dye DCF. Main roots detached from control, NaCl and mannitol stress (1 h) plants were incubated in incubation buffer for 2 h at room temperature and subsequently stained with 5 μM H2DCF-DA for 10 min. (F) The total H2O2 content according to the staining (A–F). ∗indicates significant differences between transgenic lines and WT (p < 0.05).

Mentions: To understand the regulation of physiological responses, physiological parameters involved in stresses were compared, including the ROS content, the activity of protective enzymes, such as SOD, POD, GST and GPX, EL rates and the MDA content. Staining with diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) demonstrated that H2O2 and O2- levels, respectively, in leaves were similar in WT and transgenic lines under no treatment. However, WT plants exhibited increased H2O2 and O2- accumulation compared with transgenic lines, particularly at 1 h after stress treatment, at which point the degree of staining in the transgenic lines was notably decreased compared with the WT plants (Figures 5A,B). ROS levels in intact guard cells and the main roots, as determined by stained with H2DCF, were similar to the levels indicated by DAB and NBT staining. That is, with the exception of 0 h, WT plants exhibited increased ROS accumulation in both guard cells and main roots compared with transgenic lines (Figures 5D,E). Additionally, the H2O2 content according to the degree of staining showed significantly less H2O2 in TheIF1A-transgenic plants than in WT plants (Figure 5F, p < 0.05). These findings indicate that TheIF1A overexpression leads to a significant decrease in ROS accumulation in plant cells under salt and mannitol stress conditions.


The Translation Initiation Factor 1A ( TheIF1A ) from Tamarix hispida Is Regulated by a Dof Transcription Factor and Increased Abiotic Stress Tolerance
Reactive oxygen species (ROS) levels and cell death in TheIF1A transgenic tobacco plants and WT under different stress conditions. All experiments were repeated at least three times, and approximately 15 leaves collected from multiple 28-days-old seedlings were inspected in each experiment. (A) DAB staining indicates accumulation of H2O2 in leaves of WT and transgenic plants subjected to 1, 2, or 3 h of salt or mannitol stress. (B) NBT staining of O2- accumulation in leaves according to DAB staining. (C) Evans blue staining. (D) Representative microscopy images of ROS production in intact guard cells, as indicated by the fluorescent dye DCF. Epidermal peels were loaded with H2DCF-DA for 10 min after incubation in fixing buffer for 2 h. (E) ROS production in the root, as indicated by the fluorescent dye DCF. Main roots detached from control, NaCl and mannitol stress (1 h) plants were incubated in incubation buffer for 2 h at room temperature and subsequently stained with 5 μM H2DCF-DA for 10 min. (F) The total H2O2 content according to the staining (A–F). ∗indicates significant differences between transgenic lines and WT (p < 0.05).
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Figure 5: Reactive oxygen species (ROS) levels and cell death in TheIF1A transgenic tobacco plants and WT under different stress conditions. All experiments were repeated at least three times, and approximately 15 leaves collected from multiple 28-days-old seedlings were inspected in each experiment. (A) DAB staining indicates accumulation of H2O2 in leaves of WT and transgenic plants subjected to 1, 2, or 3 h of salt or mannitol stress. (B) NBT staining of O2- accumulation in leaves according to DAB staining. (C) Evans blue staining. (D) Representative microscopy images of ROS production in intact guard cells, as indicated by the fluorescent dye DCF. Epidermal peels were loaded with H2DCF-DA for 10 min after incubation in fixing buffer for 2 h. (E) ROS production in the root, as indicated by the fluorescent dye DCF. Main roots detached from control, NaCl and mannitol stress (1 h) plants were incubated in incubation buffer for 2 h at room temperature and subsequently stained with 5 μM H2DCF-DA for 10 min. (F) The total H2O2 content according to the staining (A–F). ∗indicates significant differences between transgenic lines and WT (p < 0.05).
Mentions: To understand the regulation of physiological responses, physiological parameters involved in stresses were compared, including the ROS content, the activity of protective enzymes, such as SOD, POD, GST and GPX, EL rates and the MDA content. Staining with diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) demonstrated that H2O2 and O2- levels, respectively, in leaves were similar in WT and transgenic lines under no treatment. However, WT plants exhibited increased H2O2 and O2- accumulation compared with transgenic lines, particularly at 1 h after stress treatment, at which point the degree of staining in the transgenic lines was notably decreased compared with the WT plants (Figures 5A,B). ROS levels in intact guard cells and the main roots, as determined by stained with H2DCF, were similar to the levels indicated by DAB and NBT staining. That is, with the exception of 0 h, WT plants exhibited increased ROS accumulation in both guard cells and main roots compared with transgenic lines (Figures 5D,E). Additionally, the H2O2 content according to the degree of staining showed significantly less H2O2 in TheIF1A-transgenic plants than in WT plants (Figure 5F, p < 0.05). These findings indicate that TheIF1A overexpression leads to a significant decrease in ROS accumulation in plant cells under salt and mannitol stress conditions.

View Article: PubMed Central - PubMed

ABSTRACT

Eukaryotic translation initiation factor 1A (eIF1A) functions as an mRNA scanner and AUG initiation codon locator. However, few studies have clarified the role of eIF1A in abiotic stress. In this study, we cloned eIF1A (TheIF1A) from Tamarix hispida and found its expression to be induced by NaCl and polyethylene glycol (PEG) in roots, stems, and leaves. Compared to control, TheIF1A root expression was increased 187.63-fold when exposed to NaCl for 6 h, suggesting a potential abiotic stress response for this gene. Furthermore, transgenic tobacco plants overexpressing TheIF1A exhibited enhanced seed germination and a higher total chlorophyll content under salt and mannitol stresses. Increased superoxide dismutase, peroxidase, glutathione transferase and glutathione peroxidase activities, as well as decreased electrolyte leakage rates and malondialdehyde contents, were observed in TheIF1A-transgenic tobacco and T. hispida seedlings under salt and mannitol stresses. Histochemical staining suggested that TheIF1A improves reactive oxygen species (ROS) scavenging in plants. Moreover, TheIF1A may regulate expression of stress-related genes, including TOBLTP, GST, MnSOD, NtMPK9, poxN1, and CDPK15. Moreover, a 1352-bp promoter fragment of TheIF1A was isolated, and cis-elements were identified. Yeast one-hybrid assays showed that ThDof can specifically bind to the Dof motif present in the promoter. In addition, ThDof showed expression patterns similar to those of TheIF1A under NaCl and PEG stresses. These findings suggest the potential mechanism and physiological roles of TheIF1A. ThDof may be an upstream regulator of TheIF1A, and TheIF1A may function as a stress response regulator to improve plant salt and osmotic stress tolerance via regulation of associated enzymes and ROS scavenging, thereby reducing cell damage under stress conditions.

No MeSH data available.


Related in: MedlinePlus