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Enhancement of stress tolerance in transgenic tobacco plants constitutively expressing AtIpk2beta, an inositol polyphosphate 6-/3-kinase from Arabidopsis thaliana.

Yang L, Tang R, Zhu J, Liu H, Mueller-Roeber B, Xia H, Zhang H - Plant Mol. Biol. (2007)

Bottom Line: Here we expressed Arabidopsis inositol polyphosphate 6-/3-kinase (AtIpk2beta) in two heterologous systems, i.e. the yeast Saccharomyces cerevisiae and in tobacco (Nicotiana tabacum), and tested the effect on abiotic stress tolerance.Transgenic tobacco plants constitutively expressing AtIpk2beta under the control of the Cauliflower Mosaic Virus 35S promoter were generated and found to exhibit improved tolerance to diverse abiotic stresses when compared to wild type plants.Expression patterns of various stress responsive genes were enhanced, and the activities of anti-oxidative enzymes were elevated in transgenic plants, suggesting a possible involvement of AtIpk2beta in plant stress responses.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.

ABSTRACT
Inositol phosphates (IPs) and their turnover products have been implicated to play important roles in stress signaling in eukaryotic cells. In higher plants genes encoding inositol polyphosphate kinases have been identified previously, but their physiological functions have not been fully resolved. Here we expressed Arabidopsis inositol polyphosphate 6-/3-kinase (AtIpk2beta) in two heterologous systems, i.e. the yeast Saccharomyces cerevisiae and in tobacco (Nicotiana tabacum), and tested the effect on abiotic stress tolerance. Expression of AtIpk2beta rescued the salt-, osmotic- and temperature-sensitive growth defects of a yeast mutant strain (arg82Delta) that lacks inositol polyphosphate multikinase activity encoded by the ARG82/IPK2 gene. Transgenic tobacco plants constitutively expressing AtIpk2beta under the control of the Cauliflower Mosaic Virus 35S promoter were generated and found to exhibit improved tolerance to diverse abiotic stresses when compared to wild type plants. Expression patterns of various stress responsive genes were enhanced, and the activities of anti-oxidative enzymes were elevated in transgenic plants, suggesting a possible involvement of AtIpk2beta in plant stress responses.

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Salt tolerance test to compare wild type and AtIpk2β expressing tobacco plants. For each experiment, twelve plants of each line were used. (a) Photograph of representative wild type (WT) and transgenic plants (S13, S15) watered with 200-mM NaCl for six weeks. (b), (c) Shoot height and pod numbers of wild type (WT) and transgenic (S13, S15 ) plants treated with 200-mM NaCl. * and ** indicate significant differences in comparison to the wild type at P < 0.05 and P < 0.01, respectively (Student’s t-test). (d) Na+ content in leaves and roots of wild type (WT) and transgenic plants (S13, S15) grown in soil supplied with 0 or 200-mM NaCl solution. (e) Photograph of a representative wild type (WT) and transgenic line S15 hydroponically grown in nutrient solution supplemented with 300-mM NaCl for two months. (f) Shoot height and (g) fresh weight of wild type (WT) and transgenic lines S13 and S15 grown for two months under control (0-mM NaCl) or high salt (300-mM NaCl) conditions. Results are presented as means and standard errors from three independent experiments. ** indicates significant differences in comparison to the wild type at P < 0.01 (Student’s t-test)
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Fig4: Salt tolerance test to compare wild type and AtIpk2β expressing tobacco plants. For each experiment, twelve plants of each line were used. (a) Photograph of representative wild type (WT) and transgenic plants (S13, S15) watered with 200-mM NaCl for six weeks. (b), (c) Shoot height and pod numbers of wild type (WT) and transgenic (S13, S15 ) plants treated with 200-mM NaCl. * and ** indicate significant differences in comparison to the wild type at P < 0.05 and P < 0.01, respectively (Student’s t-test). (d) Na+ content in leaves and roots of wild type (WT) and transgenic plants (S13, S15) grown in soil supplied with 0 or 200-mM NaCl solution. (e) Photograph of a representative wild type (WT) and transgenic line S15 hydroponically grown in nutrient solution supplemented with 300-mM NaCl for two months. (f) Shoot height and (g) fresh weight of wild type (WT) and transgenic lines S13 and S15 grown for two months under control (0-mM NaCl) or high salt (300-mM NaCl) conditions. Results are presented as means and standard errors from three independent experiments. ** indicates significant differences in comparison to the wild type at P < 0.01 (Student’s t-test)

Mentions: We also performed salt tolerance experiments with wild type and two transgenic lines grown in the greenhouse in soil. The plants were watered bi-weekly with 1/8 concentrated MS salt solution supplemented with or without 200-mM NaCl. After six weeks, distinct differences were observed between wild type and transgenic plants exposed to 200-mM NaCl (Fig. 4a). Although both sets of plants flowered under conditions of salt stress, wild type plants developed much shorter stems (Fig. 4b), produced fewer pods (Fig. 4c), and produced seeds that were not viable. We determined endogenous Na+ levels in leaves and roots of wild type and transgenic plants grown in the absence or presence of 200-mM NaCl. Both wild type and transgenic plants exposed to salt contained elevated levels of Na+ ions in leaves and roots (Fig. 4d), however, ion concentrations were not significantly different between wild type and transgenic plants (the same was true for plants grown under normal conditions). We also grew tobacco plants in hydroponic culture. In the absence of salt stress, no overt morphological difference was observed between wild type and transgenic plants. However, growth of wild type tobacco was severely inhibited in the presence of 300-mM NaCl (Fig. 4e), leading to a depression of shoot height by about one third, and of plant fresh weight by about 50% in comparison to AtIpk2β expressing tobacco plants after a two-month stress treatment (Fig. 4f). All these results indicated that AtIpk2β alleviated the negative effects imposed by salt stress on plant growth.Fig. 4


Enhancement of stress tolerance in transgenic tobacco plants constitutively expressing AtIpk2beta, an inositol polyphosphate 6-/3-kinase from Arabidopsis thaliana.

Yang L, Tang R, Zhu J, Liu H, Mueller-Roeber B, Xia H, Zhang H - Plant Mol. Biol. (2007)

Salt tolerance test to compare wild type and AtIpk2β expressing tobacco plants. For each experiment, twelve plants of each line were used. (a) Photograph of representative wild type (WT) and transgenic plants (S13, S15) watered with 200-mM NaCl for six weeks. (b), (c) Shoot height and pod numbers of wild type (WT) and transgenic (S13, S15 ) plants treated with 200-mM NaCl. * and ** indicate significant differences in comparison to the wild type at P < 0.05 and P < 0.01, respectively (Student’s t-test). (d) Na+ content in leaves and roots of wild type (WT) and transgenic plants (S13, S15) grown in soil supplied with 0 or 200-mM NaCl solution. (e) Photograph of a representative wild type (WT) and transgenic line S15 hydroponically grown in nutrient solution supplemented with 300-mM NaCl for two months. (f) Shoot height and (g) fresh weight of wild type (WT) and transgenic lines S13 and S15 grown for two months under control (0-mM NaCl) or high salt (300-mM NaCl) conditions. Results are presented as means and standard errors from three independent experiments. ** indicates significant differences in comparison to the wild type at P < 0.01 (Student’s t-test)
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Related In: Results  -  Collection

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Fig4: Salt tolerance test to compare wild type and AtIpk2β expressing tobacco plants. For each experiment, twelve plants of each line were used. (a) Photograph of representative wild type (WT) and transgenic plants (S13, S15) watered with 200-mM NaCl for six weeks. (b), (c) Shoot height and pod numbers of wild type (WT) and transgenic (S13, S15 ) plants treated with 200-mM NaCl. * and ** indicate significant differences in comparison to the wild type at P < 0.05 and P < 0.01, respectively (Student’s t-test). (d) Na+ content in leaves and roots of wild type (WT) and transgenic plants (S13, S15) grown in soil supplied with 0 or 200-mM NaCl solution. (e) Photograph of a representative wild type (WT) and transgenic line S15 hydroponically grown in nutrient solution supplemented with 300-mM NaCl for two months. (f) Shoot height and (g) fresh weight of wild type (WT) and transgenic lines S13 and S15 grown for two months under control (0-mM NaCl) or high salt (300-mM NaCl) conditions. Results are presented as means and standard errors from three independent experiments. ** indicates significant differences in comparison to the wild type at P < 0.01 (Student’s t-test)
Mentions: We also performed salt tolerance experiments with wild type and two transgenic lines grown in the greenhouse in soil. The plants were watered bi-weekly with 1/8 concentrated MS salt solution supplemented with or without 200-mM NaCl. After six weeks, distinct differences were observed between wild type and transgenic plants exposed to 200-mM NaCl (Fig. 4a). Although both sets of plants flowered under conditions of salt stress, wild type plants developed much shorter stems (Fig. 4b), produced fewer pods (Fig. 4c), and produced seeds that were not viable. We determined endogenous Na+ levels in leaves and roots of wild type and transgenic plants grown in the absence or presence of 200-mM NaCl. Both wild type and transgenic plants exposed to salt contained elevated levels of Na+ ions in leaves and roots (Fig. 4d), however, ion concentrations were not significantly different between wild type and transgenic plants (the same was true for plants grown under normal conditions). We also grew tobacco plants in hydroponic culture. In the absence of salt stress, no overt morphological difference was observed between wild type and transgenic plants. However, growth of wild type tobacco was severely inhibited in the presence of 300-mM NaCl (Fig. 4e), leading to a depression of shoot height by about one third, and of plant fresh weight by about 50% in comparison to AtIpk2β expressing tobacco plants after a two-month stress treatment (Fig. 4f). All these results indicated that AtIpk2β alleviated the negative effects imposed by salt stress on plant growth.Fig. 4

Bottom Line: Here we expressed Arabidopsis inositol polyphosphate 6-/3-kinase (AtIpk2beta) in two heterologous systems, i.e. the yeast Saccharomyces cerevisiae and in tobacco (Nicotiana tabacum), and tested the effect on abiotic stress tolerance.Transgenic tobacco plants constitutively expressing AtIpk2beta under the control of the Cauliflower Mosaic Virus 35S promoter were generated and found to exhibit improved tolerance to diverse abiotic stresses when compared to wild type plants.Expression patterns of various stress responsive genes were enhanced, and the activities of anti-oxidative enzymes were elevated in transgenic plants, suggesting a possible involvement of AtIpk2beta in plant stress responses.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.

ABSTRACT
Inositol phosphates (IPs) and their turnover products have been implicated to play important roles in stress signaling in eukaryotic cells. In higher plants genes encoding inositol polyphosphate kinases have been identified previously, but their physiological functions have not been fully resolved. Here we expressed Arabidopsis inositol polyphosphate 6-/3-kinase (AtIpk2beta) in two heterologous systems, i.e. the yeast Saccharomyces cerevisiae and in tobacco (Nicotiana tabacum), and tested the effect on abiotic stress tolerance. Expression of AtIpk2beta rescued the salt-, osmotic- and temperature-sensitive growth defects of a yeast mutant strain (arg82Delta) that lacks inositol polyphosphate multikinase activity encoded by the ARG82/IPK2 gene. Transgenic tobacco plants constitutively expressing AtIpk2beta under the control of the Cauliflower Mosaic Virus 35S promoter were generated and found to exhibit improved tolerance to diverse abiotic stresses when compared to wild type plants. Expression patterns of various stress responsive genes were enhanced, and the activities of anti-oxidative enzymes were elevated in transgenic plants, suggesting a possible involvement of AtIpk2beta in plant stress responses.

Show MeSH
Related in: MedlinePlus