Heterologous expression of the peach sucrose transporter (PpSUT2) in increased cold and drought stress tolerance in tobacco

ABSTRACT

Peach is an important fruit tree worldwide. Sucrose transporters (SUTs) have been extensively studied in relation to plant growth, development, and stress responses. In this study, we cloned a putative SUT, PpSUT2, from the peach cultivar ‘New Kawanakajima.’ Bioinformatics analysis predicted that the protein had functional domains typical of the GPH_sucrose family. Phylogenetic analysis revealed high sequence similarity between PpSUT2 and SUTs from other plant species. The qRT-PCR suggested that PpSUT2 was expressed concurrently in the petals, sepals, pistils, stamen, phloem, and leaves. Different trends and different relative expression levels were observed during the flowering and fruit development periods. Western blot analysis produced similar results. The heterologous expression of SUTs in the defective yeast SUSY7/ura3 showed that PpSUT2 had a complementary function on SD sucrose medium. This indicated that it had sucrose transport activity and might be a signal protein. Then, 11PpSUT2 transgenic tobacco plants were obtained.After exposure to low temperature and drought stress conditions, the transgenic overexpression plants exhibited increased proline and soluble sugar content, reduced malondialdehyde (MDA) content and reduced relative conductivity, and less membrane injury. These results suggest that the overexpression of PpSUT2 in tobacco promoted greater resistance to cold and drought.

KEYWORDS:

• Peach
• sucrose transporter
• PpSUT2
• cold stress
• drought treatment

Acknowledgments

We thank Dr. John Ward of the University of Minnesota for providing the yeast SUSY7/ura3 strain and Drs. Li-jun Wang and Li-qin Cheng of the Institute of Botany at the Chinese Academy of Sciences for the pDR196 vector and pDRl96-StSUT1 plasmid.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant No. 30500172), the Major Science and Technology Project in Henan Province (grant No. 151100110900), and the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (grant No. IDHT20140509).