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Overexpression of the soybean GmERF3 gene, an AP2/ERF type transcription factor for increased tolerances to salt, drought, and diseases in transgenic tobacco.

Zhang G, Chen M, Li L, Xu Z, Chen X, Guo J, Ma Y - J. Exp. Bot. (2009)

Bottom Line: The GmERF3 protein fused to the GAL4 DNA-binding domain to activate transcription of reporter genes in yeast.Furthermore, overexpression of GmERF3 in transgenic tobacco led to higher levels of free proline and soluble carbohydrates compared to wild-type plants under drought conditions.The overall results suggested that GmERF3 as an AP2/ERF transcription factor may play dual roles in response to biotic and abiotic stresses in plants.

View Article: PubMed Central - PubMed

Affiliation: The National Key Facility for Crop Genetic Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.

ABSTRACT
A new member of the AP2/ERF transcription factor family, GmERF3, was isolated from soybean. Sequence analysis showed that GmERF3 contained an AP2/ERF domain of 58 amino acids and two putative nuclear localization signal (NLS) domains. It belonged to a group IV protein in the ERF (ethylene response factor) subfamily as typified by a conserved N-terminal motif [MCGGAI(I/L)]. Expression of GmERF3 was induced by treatments with high salinity, drought, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and soybean mosaic virus (SMV), whereas there was no significant GmERF3 mRNA accumulation under cold stress treatment. GmERF3 could bind to the GCC box and DRE/CRT element, and was targeted to the nucleus when transiently expressed in onion epidermal cells. The GmERF3 protein fused to the GAL4 DNA-binding domain to activate transcription of reporter genes in yeast. Ectopic expression of the GmERF3 gene in transgenic tobacco plants induced the expression of some PR genes and enhanced resistance against infection by Ralstonia solanacearum, Alternaria alternata, and tobacco mosaic virus (TMV), and gave tolerance to high salinity and dehydration stresses. Furthermore, overexpression of GmERF3 in transgenic tobacco led to higher levels of free proline and soluble carbohydrates compared to wild-type plants under drought conditions. The overall results suggested that GmERF3 as an AP2/ERF transcription factor may play dual roles in response to biotic and abiotic stresses in plants.

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Effects of water stress on free proline and soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. Wild-type and 35S::GmERF3 transgenic tobacco plants were grown under normal conditions for 7 weeks and then exposed to water deprivation stress for 28 d, before resumption of normal conditions. Volumetric soil water content was measured and samples for total soluble carbohydrates and proline contents measurements were taken at different times as indicated. (A) Comparison of volumetric soil water contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (B) Free proline contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (C) Soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. WT, wild-type control; G1–G4, different transgenic lines.
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fig9: Effects of water stress on free proline and soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. Wild-type and 35S::GmERF3 transgenic tobacco plants were grown under normal conditions for 7 weeks and then exposed to water deprivation stress for 28 d, before resumption of normal conditions. Volumetric soil water content was measured and samples for total soluble carbohydrates and proline contents measurements were taken at different times as indicated. (A) Comparison of volumetric soil water contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (B) Free proline contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (C) Soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. WT, wild-type control; G1–G4, different transgenic lines.

Mentions: To evaluate physiological changes in transgenic plants, the contents of free proline and soluble carbohydrates as osmotic regulators in the wild-type and 35S::GmERF3 transgenic tobaccos were measured following drought stress. Under normal growth conditions, free proline concentrations in GmERF3-overexpressing plants were approximately 2-fold higher than those in the control plants (P <0.01) (Fig. 9B). During drought treatment, the contents of proline in both GmERF3 transgenic plants and the control plants rose continuously. This effect was especially significant after 14 d. After 4 weeks, transgenic line G3 had the highest proline content, 5-fold that in the control (P <0.01). The content of proline in other transgenic plants was also higher than the control (Fig. 9B). The level of proline accumulation decreased significantly during the recovery period. Furthermore, volumetric soil water content of the transgenic lines at different time points under drought stress were about the same as those of the control plants. Both decreased gradually and returned to the normal level 7 d after rewatering (Fig. 9A). Comparison of soluble carbohydrates in wild-type and GmERF3 transgenic plants showed remarkably higher levels of soluble carbohydrates in transgenic plants than wild-type plants. A low but significant amount of soluble sugars was detected in wild-type plants; these levels increased significantly under drought stress. Transgenic plants grown under control conditions exhibited levels of soluble carbohydrates comparable with wild-type plants (Fig. 9C). After drought stress, the transgenic lines (G1–G4) showed 1.5–2 times higher levels of soluble sugars compared to wild type plants (P <0.05) (Fig. 9C).


Overexpression of the soybean GmERF3 gene, an AP2/ERF type transcription factor for increased tolerances to salt, drought, and diseases in transgenic tobacco.

Zhang G, Chen M, Li L, Xu Z, Chen X, Guo J, Ma Y - J. Exp. Bot. (2009)

Effects of water stress on free proline and soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. Wild-type and 35S::GmERF3 transgenic tobacco plants were grown under normal conditions for 7 weeks and then exposed to water deprivation stress for 28 d, before resumption of normal conditions. Volumetric soil water content was measured and samples for total soluble carbohydrates and proline contents measurements were taken at different times as indicated. (A) Comparison of volumetric soil water contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (B) Free proline contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (C) Soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. WT, wild-type control; G1–G4, different transgenic lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2736888&req=5

fig9: Effects of water stress on free proline and soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. Wild-type and 35S::GmERF3 transgenic tobacco plants were grown under normal conditions for 7 weeks and then exposed to water deprivation stress for 28 d, before resumption of normal conditions. Volumetric soil water content was measured and samples for total soluble carbohydrates and proline contents measurements were taken at different times as indicated. (A) Comparison of volumetric soil water contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (B) Free proline contents of wild-type and 35S::GmERF3 transgenic tobacco plants. (C) Soluble carbohydrate contents of wild-type and 35S::GmERF3 transgenic tobacco plants. WT, wild-type control; G1–G4, different transgenic lines.
Mentions: To evaluate physiological changes in transgenic plants, the contents of free proline and soluble carbohydrates as osmotic regulators in the wild-type and 35S::GmERF3 transgenic tobaccos were measured following drought stress. Under normal growth conditions, free proline concentrations in GmERF3-overexpressing plants were approximately 2-fold higher than those in the control plants (P <0.01) (Fig. 9B). During drought treatment, the contents of proline in both GmERF3 transgenic plants and the control plants rose continuously. This effect was especially significant after 14 d. After 4 weeks, transgenic line G3 had the highest proline content, 5-fold that in the control (P <0.01). The content of proline in other transgenic plants was also higher than the control (Fig. 9B). The level of proline accumulation decreased significantly during the recovery period. Furthermore, volumetric soil water content of the transgenic lines at different time points under drought stress were about the same as those of the control plants. Both decreased gradually and returned to the normal level 7 d after rewatering (Fig. 9A). Comparison of soluble carbohydrates in wild-type and GmERF3 transgenic plants showed remarkably higher levels of soluble carbohydrates in transgenic plants than wild-type plants. A low but significant amount of soluble sugars was detected in wild-type plants; these levels increased significantly under drought stress. Transgenic plants grown under control conditions exhibited levels of soluble carbohydrates comparable with wild-type plants (Fig. 9C). After drought stress, the transgenic lines (G1–G4) showed 1.5–2 times higher levels of soluble sugars compared to wild type plants (P <0.05) (Fig. 9C).

Bottom Line: The GmERF3 protein fused to the GAL4 DNA-binding domain to activate transcription of reporter genes in yeast.Furthermore, overexpression of GmERF3 in transgenic tobacco led to higher levels of free proline and soluble carbohydrates compared to wild-type plants under drought conditions.The overall results suggested that GmERF3 as an AP2/ERF transcription factor may play dual roles in response to biotic and abiotic stresses in plants.

View Article: PubMed Central - PubMed

Affiliation: The National Key Facility for Crop Genetic Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.

ABSTRACT
A new member of the AP2/ERF transcription factor family, GmERF3, was isolated from soybean. Sequence analysis showed that GmERF3 contained an AP2/ERF domain of 58 amino acids and two putative nuclear localization signal (NLS) domains. It belonged to a group IV protein in the ERF (ethylene response factor) subfamily as typified by a conserved N-terminal motif [MCGGAI(I/L)]. Expression of GmERF3 was induced by treatments with high salinity, drought, abscisic acid (ABA), salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and soybean mosaic virus (SMV), whereas there was no significant GmERF3 mRNA accumulation under cold stress treatment. GmERF3 could bind to the GCC box and DRE/CRT element, and was targeted to the nucleus when transiently expressed in onion epidermal cells. The GmERF3 protein fused to the GAL4 DNA-binding domain to activate transcription of reporter genes in yeast. Ectopic expression of the GmERF3 gene in transgenic tobacco plants induced the expression of some PR genes and enhanced resistance against infection by Ralstonia solanacearum, Alternaria alternata, and tobacco mosaic virus (TMV), and gave tolerance to high salinity and dehydration stresses. Furthermore, overexpression of GmERF3 in transgenic tobacco led to higher levels of free proline and soluble carbohydrates compared to wild-type plants under drought conditions. The overall results suggested that GmERF3 as an AP2/ERF transcription factor may play dual roles in response to biotic and abiotic stresses in plants.

Show MeSH
Related in: MedlinePlus