过表达PsnSWEET7重塑碳氮代谢并促进小黑杨生长

doi:10.7525/j.issn.1673-5102.2026.04.007

摘要/Abstract

摘要：

为研究PsnSWEET7在氮素响应和碳氮代谢调控中的功能，以小黑杨（Populus simonii×P. nigra）为试验材料，通过农杆菌（Agrobacterium）介导法创制过表达转基因株系，结合亚细胞定位及不同浓度氮素（NH₄NO₃）处理下表型分析、生理指标测定、基因表达分析等方法，系统探究该基因对植株生长及碳氮代谢的影响。分析显示：PsnSWEET7蛋白定位于质膜；在NH₄NO₃处理下，相较于野生型，PsnSWEET7过表达植株株高与地径分别显著增加17.3%和17.8%（P<0.05）；茎部蔗糖、葡萄糖质量分数分别显著提高20.1%和25.4%（P<0.05），可溶性蛋白及游离氨基酸质量分数分别显著提高9.3%和7.5%（P<0.05）；纤维素质量分数显著提高10.5%（P<0.05），木质素质量分数显著下降12.2%（P<0.05）。在正常和高氮条件下，转基因植株液泡转化酶与细胞壁转化酶活性显著提高（P<0.05）。结果表明，PsnSWEET7可通过调控糖转运重塑小黑杨碳氮代谢，进而促进植株生长。研究结果为高产优质杨树分子育种提供了新的基因资源与理论依据。

关键词: 小黑杨, PsnSWEET7, 氮素处理, 生理指标

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

中图分类号:

S718.43

雷学坤, 侯照银, 杨元植, 许志茹, 刘关君. 过表达PsnSWEET7重塑碳氮代谢并促进小黑杨生长[J]. 植物研究, 2026, 46(4): 655-665.

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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