The SlNAC2 transcription factor from tomato confers tolerance to drought stress in transgenic tobacco plants |
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Authors: | Coenraad R. van Beek Tapiwa Guzha Nolusindiso Kopana Cornelius S. van der Westhuizen Sanjib K. Panda Christell van der Vyver |
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Affiliation: | 1.Institute for Plant Biotechnology, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7601 South Africa ;2.Department of Genetics, University of Stellenbosch, Stellenbosch, 7601 South Africa ;3.Department of Biochemistry, Central University of Rajasthan, Rajasthan, 305817 India |
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Abstract: | Drought is a key environmental factor that restricts crop growth and productivity. Plant responses to water-deficit stress at the whole plant level are mediated by stress-response gene expression through the action of transcription factors (TF). The NAC (NAM/ATAF/CUC) transcription factor family has been well documented in its role in improving plant abiotic stress tolerance. In the present study we evaluated the effects of overexpression of SlNAC2 TF on the photosynthetic machinery, relative water content (RWC), reactive oxygen species, antioxidants and proline levels in tobacco plants exposed to a water-deficit treatment. Shoot growth and seed formation were also evaluated before, during and following water-deficit to determine any morphological consequences of transgene expression. The transgenic plants maintained higher RWC and chlorophyll levels over 21 days after withholding water and stomatal conductance until the 16th day of water-deficit. Overexpression of SlNAC2 in tobacco increased proline levels, improved seed setting and delayed leaf senescence of the transgenic plants. Reactive oxygen species accumulated at lower levels in the dehydrated transgenic plants but no significant difference in superoxide dismutase and catalase content were seen between the genotypes. The conversion of glutathione to oxidized glutathione was significantly higher in the transgenic plants, supported by increased glutathione reductase transcript levels. Our results indicate that overexpression of SlNAC2 in tobacco improved survival during and recovery from water-deficit stress, without an associated biomass penalty under irrigation.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-00996-2. |
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Keywords: | Transcription factor NAC2 SlNAC2 Tobacco Tomato Drought stress Abiotic stress |
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