Abstract
We previously reported that transgenic wheat (Triticum aestivum L.) carrying a maize (Zea mays L.) gene (Zmeftu1) for chloroplast protein synthesis elongation factor, EF-Tu, displays reduced thermal aggregation of leaf proteins, reduced injury to photosynthetic membranes (thylakoids), and enhanced rate of CO2 fixation following exposure to heat stress (18 h at 45°C) [Fu et al. in Plant Mol Biol 68:277–288, 2008]. In the current study, we investigated the segregation pattern and expression of the transgene Zmeftu1 and determined the grain yield of transgenic plants after exposure to a brief heat stress (18 h at 45°C). We also assessed thermal aggregation of soluble leaf proteins in transgenic plants, testing the hypothesis that increased levels of EF-Tu will lead to a non-specific protection of leaf proteins against thermal aggregation. The transgenic wheat displayed a single-gene pattern of segregation of Zmeftu1. Zmeftu1 was expressed, and the transgenic plants synthesized and accumulated three anti-EF-Tu cross-reacting polypeptides of similar molecular mass but different pI, suggesting the possibility of posttranslational modification of this protein. The transgenic plants also showed better grain yield after exposure to heat stress compared with their non-transgenic counterparts. Soluble leaf proteins of various molecular masses displayed lower thermal aggregation in transgenic than in non-transgenic wheat. The results suggest that overexpression of chloroplast EF-Tu can be beneficial to wheat tolerance to heat stress. Moreover, the results also support the hypothesis that EF-Tu contributes to heat tolerance by acting as a molecular chaperone and protecting heat-labile proteins from thermal aggregation in a non-specific manner.
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Acknowledgments
The authors are thankful to Dr. Thomas E. Elthon, University of Nebraska, Lincoln, NE, Dr. Guihua Bai, USDA-ARS, Manhattan, KS, and Dr. Mark West, USDA-ARS, Fort Collins, CO, for critical reading of the manuscript. This publication is contribution No. 09-326-J from the Kansas Agriculture Experiment Station. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the United States Department of Agriculture and does not imply its approval to the exclusion of other products which may also be suitable.
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Fu, J., Ristic, Z. Analysis of transgenic wheat (Triticum aestivum L.) harboring a maize (Zea mays L.) gene for plastid EF-Tu: segregation pattern, expression and effects of the transgene. Plant Mol Biol 73, 339–347 (2010). https://doi.org/10.1007/s11103-010-9622-7
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DOI: https://doi.org/10.1007/s11103-010-9622-7