Overexpression of PsnSWEET7 Remodels Carbon-Nitrogen Metabolism and Promotes Growth in Populus simonii×P. nigra

doi:10.7525/j.issn.1673-5102.2026.04.007

Abstract

Abstract:

To investigate the function of PsnSWEET7 in nitrogen response and regulation of carbon and nitrogen metabolism， the transgenic lines overexpressing PsnSWEET7 were generated in Populus simonii × P. nigra via Agrobacterium-mediated transformation. The effects of this gene on plant growth and carbon-nitrogen metabolism were investigated by subcellular localization and phenotype analysis，as well as determinations of physiological indices and gene expression under treatments with different concentrations of ammonium nitrate （NH₄NO₃）. The PsnSWEET7 protein was localized to the plasma membrane. Under NH₄NO₃ treatments， compared with the wild type， the plant height and ground diameter of PsnSWEET7 overexpressing plants increased by 17.3% and 17.8%， respectively（P<0.05）； the mass fractions of sucrose， glucose， soluble protein and free amino acids in stems increased by 20.1%， 25.4%， 9.3% and 7.5%， respectively（P<0.05）； the cellulose mass fraction increased by 10.5%（P<0.05）， while the lignin mass fraction decreased by 12.2%（P<0.05）. Under normal and high nitrogen conditions， the activities of vacuolar invertase and cell wall invertase were significantly elevated in transgenic plants. This study indicates that PsnSWEET7 can remodel the carbon and nitrogen metabolism of P.simonii×P. nigra by regulating sugar transport， thereby promoting plant growth， and provides new genetic resources and theoretical basis for the molecular breeding of high-yield and high-quality poplars.

Key words: Populus simonii×P.nigra, PsnSWEET7, nitrogen treatment, physiological indices

CLC Number:

S718.43

Xuekun LEI, Zhaoyin HOU, Yuanzhi YANG, Zhiru XU, Guanjun LIU. Overexpression of PsnSWEET7 Remodels Carbon-Nitrogen Metabolism and Promotes Growth in Populus simonii×P. nigra[J]. Bulletin of Botanical Research, 2026, 46(4): 655-665.

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