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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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GmERF3 enhances tolerance to salt and drought in tobacco. (A) Chlorophyll contents in transgenic tobacco leaf tissues after salt treatment. Leaf discs from transgenic plants carrying the GmERF3 gene and wild-type plants were floated on half-strength MS liquid medium containing 400 mM NaCl for 5 d. As a control, wild-type leaf discs were floated on half-strength MS liquid medium. Phenotypic differences were observed and chlorophyll contents (mg g−1 fresh weight) were measured from NaCl-treated leaf discs of 35S::GmERF3 transgenic and wild-type tobacco plants. The experiments were repeated twice, each time with 4–8 leaf discs. (B) Phenotypes on half-strength MS medium containing 200 mM NaCl or 2% PEG were photographed 30 d after treatment. Control indicates seedlings before treatment. (C) Root lengths of seedlings after salt treatment; the data shown are relative to the control plus SD. (D) Root lengths of seedlings after drought treatment; data are relative to the control plus SD. (This figure is available in colour at JXB online.)
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fig8: GmERF3 enhances tolerance to salt and drought in tobacco. (A) Chlorophyll contents in transgenic tobacco leaf tissues after salt treatment. Leaf discs from transgenic plants carrying the GmERF3 gene and wild-type plants were floated on half-strength MS liquid medium containing 400 mM NaCl for 5 d. As a control, wild-type leaf discs were floated on half-strength MS liquid medium. Phenotypic differences were observed and chlorophyll contents (mg g−1 fresh weight) were measured from NaCl-treated leaf discs of 35S::GmERF3 transgenic and wild-type tobacco plants. The experiments were repeated twice, each time with 4–8 leaf discs. (B) Phenotypes on half-strength MS medium containing 200 mM NaCl or 2% PEG were photographed 30 d after treatment. Control indicates seedlings before treatment. (C) Root lengths of seedlings after salt treatment; the data shown are relative to the control plus SD. (D) Root lengths of seedlings after drought treatment; data are relative to the control plus SD. (This figure is available in colour at JXB online.)

Mentions: In order to test whether GmERF3 overexpression changes the response of plants to abiotic stresses, leaf discs of transgenic and wild-type tobacco plants were first floated on MS solution containing 400 mM NaCl for 5 d and plant salt tolerances were examined by comparing phenotypes and chlorophyll contents. After 5 d of salt treatment, leaf discs from the wild type were bleached, whereas leaf discs from transgenic GmERF3 plants remained green (upper panel, Fig. 8A). Chlorophyll content measurements in these plants confirmed the observed phenotypic differences (Fig. 8A, lower panel). Although there were differences between transgenic lines, their abilities to tolerate salt were higher than those of wild-type plants. Shoot tips excised from aseptic seedlings of both wild-type and GmERF3 transgenic tobacco were transferred to half-strength MS medium containing 200 mM NaCl. Significant phenotypic differences between wild-type plants and transgenic lines were observed after 30 d (Fig. 8B, middle panel). During that period, leaves of wild-type plants gradually lost greenness and root elongation was severely retarded, whereas leaves of the transgenic plants remained green and the roots displayed tolerance against salt stress (Fig. 8C). Root formation on wild-type plants was zero.


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)

GmERF3 enhances tolerance to salt and drought in tobacco. (A) Chlorophyll contents in transgenic tobacco leaf tissues after salt treatment. Leaf discs from transgenic plants carrying the GmERF3 gene and wild-type plants were floated on half-strength MS liquid medium containing 400 mM NaCl for 5 d. As a control, wild-type leaf discs were floated on half-strength MS liquid medium. Phenotypic differences were observed and chlorophyll contents (mg g−1 fresh weight) were measured from NaCl-treated leaf discs of 35S::GmERF3 transgenic and wild-type tobacco plants. The experiments were repeated twice, each time with 4–8 leaf discs. (B) Phenotypes on half-strength MS medium containing 200 mM NaCl or 2% PEG were photographed 30 d after treatment. Control indicates seedlings before treatment. (C) Root lengths of seedlings after salt treatment; the data shown are relative to the control plus SD. (D) Root lengths of seedlings after drought treatment; data are relative to the control plus SD. (This figure is available in colour at JXB online.)
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig8: GmERF3 enhances tolerance to salt and drought in tobacco. (A) Chlorophyll contents in transgenic tobacco leaf tissues after salt treatment. Leaf discs from transgenic plants carrying the GmERF3 gene and wild-type plants were floated on half-strength MS liquid medium containing 400 mM NaCl for 5 d. As a control, wild-type leaf discs were floated on half-strength MS liquid medium. Phenotypic differences were observed and chlorophyll contents (mg g−1 fresh weight) were measured from NaCl-treated leaf discs of 35S::GmERF3 transgenic and wild-type tobacco plants. The experiments were repeated twice, each time with 4–8 leaf discs. (B) Phenotypes on half-strength MS medium containing 200 mM NaCl or 2% PEG were photographed 30 d after treatment. Control indicates seedlings before treatment. (C) Root lengths of seedlings after salt treatment; the data shown are relative to the control plus SD. (D) Root lengths of seedlings after drought treatment; data are relative to the control plus SD. (This figure is available in colour at JXB online.)
Mentions: In order to test whether GmERF3 overexpression changes the response of plants to abiotic stresses, leaf discs of transgenic and wild-type tobacco plants were first floated on MS solution containing 400 mM NaCl for 5 d and plant salt tolerances were examined by comparing phenotypes and chlorophyll contents. After 5 d of salt treatment, leaf discs from the wild type were bleached, whereas leaf discs from transgenic GmERF3 plants remained green (upper panel, Fig. 8A). Chlorophyll content measurements in these plants confirmed the observed phenotypic differences (Fig. 8A, lower panel). Although there were differences between transgenic lines, their abilities to tolerate salt were higher than those of wild-type plants. Shoot tips excised from aseptic seedlings of both wild-type and GmERF3 transgenic tobacco were transferred to half-strength MS medium containing 200 mM NaCl. Significant phenotypic differences between wild-type plants and transgenic lines were observed after 30 d (Fig. 8B, middle panel). During that period, leaves of wild-type plants gradually lost greenness and root elongation was severely retarded, whereas leaves of the transgenic plants remained green and the roots displayed tolerance against salt stress (Fig. 8C). Root formation on wild-type plants was zero.

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