Introduction of the carrot HSP17.7 into potato (Solanum tuberosum L.) enhances cellular membrane stability and tuberization in vitro

Authors

  • YEH-JIN AHN,

    1. Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
    Search for more papers by this author
    • *

      Present address: Crop Improvement & Utilization, Western Regional Research Center, US Department of Agriculture, Agricultural Research Service, 800 Buchanan Street, Albany, CA 94710, USA.

  • J. LYNN ZIMMERMAN

    Corresponding author
    1. Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
      Yeh-Jin Ahn. Fax: +1 510 5595768; e-mail: yjahn@pw.usda.gov
    Search for more papers by this author

Yeh-Jin Ahn. Fax: +1 510 5595768; e-mail: yjahn@pw.usda.gov

ABSTRACT

We have examined the ability of a carrot (Daucus carota L.) heat shock protein gene encoding HSP17.7 (DcHSP17.7) to confer enhanced heat tolerance to potato (Solanum tuberosum L.), a cool-season crop. The DcHSP17.7 gene was fused to a 6XHistidine (His) tag to distinguish the engineered protein from endogenous potato proteins and was introduced into the potato cultivar ‘Désirée’ under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Western analysis showed that engineered DcHSP17.7 was constitutively, but not abundantly, expressed in transgenic potato lines before heat stress. Leaves from multiple regenerated potato lines that contain the transgene exhibited significantly improved cellular membrane stability at high temperatures, compared with wild-type and vector control plants. Transgenic potato lines also exhibited enhanced tuberization in vitro: under a condition of constant heat stress, at 29 °C, nodal sections of the transgenic lines produced larger and heavier microtubers at higher rates, compared to the wild type and vector controls. The dry weight and percentages of microtubers that were longer than 5 mm were up to three times higher in the transgenic lines. Our results suggest that constitutive expression of carrot HSP17.7 can enhance thermotolerance in transgenic potato plants. To our knowledge, this is the first study that shows that the thermotolerance of potato can be enhanced through gene transfer.

Ancillary