Thellungiella halophila ST5 improves salt tolerance in cotton

Abstract

Background: Salinity is a major abiotic stress to global agriculture which hampers crop growth and development, and eventually reduces yield. Transgenic technology is an effective and efficient approach to improve crop salt tolerance but depending on the availability of effective genes. We previously isolated Salt Tolerance5 (ThST5) from the halophyte Thellungiella halophila, an ortholog of Arabidopsis SPT4-2 which encodes a transcription elongation factor. However, SPT4-2-confered salt tolerance has not been evaluated in crops yet. Here we report the evaluation of ThST5-conferred salt tolerance in cotton (Gossypium hirsutum L.). Results: The ThST5 overexpression transgenic cotton plants displayed enhanced tolerance to salt stress during seed germination and seedling stage compared with wild type. Particularly, the transgenic plants showed improved salinity tolerance as well as yield under saline field conditions. Comparative transcriptomic analysis showed that ThST5 improved salt tolerance of transgenic cotton mainly by maintaining ion homeostasis. In addition, ThST5 also orchestrated the expression of genes encoding antioxidants and salt-responsive transcription factors. Conclusion: Our results demonstrate that ThST5 is a promising candidate to improve salt tolerance in cotton.