PIN5 is involved in regulating NH4+ efflux and primary root growth under high-ammonium stress via mediating intracellular auxin transport

文献类型: 外文期刊

第一作者: Di, Dong-Wei

作者: Di, Dong-Wei;Ma, Mingkun;Li, Guangjie;Wang, Meng;Shi, Weiming;Wu, Jingjing;Ma, Mingkun;Shi, Weiming;Kronzucker, Herbert J.

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关键词: PIN5; Ammonium; Intracellular auxin homeostasis; H+ fluxes; NH4+ fluxes

期刊名称:PLANT AND SOIL ( 影响因子:4.9; 五年影响因子:5.2 )

ISSN: 0032-079X

年卷期: 2023 年

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收录情况: SCI

摘要: Background and Aims Ammonium (NH4+) is an important nitrogen (N) source in many ecosystems and agricultural systems but excessive NH4+ is toxic to root growth and development, especially when NH4+ is the sole N source. Previous studies have shown that polar auxin (indole-3-acetic acid, IAA) transport mediated by PIN2 and AUX1 is critical for maintaining lateral root development under high-NH4+ stress. However, the regulation of subcellular IAA homeostasis under high-NH4+ stress has remained unclear.Methods Knockout mutants for the intracellular IAA transporter PIN5 and the plasma-membrane H+-ATPases AHA1 and AHA2 were used, and primary root length, transmembrane H+ fluxes, and NH4+ fluxes in the roots were determined.Results We show that high NH4+ disturbs the subcellular IAA homeostasis by upregulating the expression of PIN5. Knockout of PIN5 resulted in elevated cytoplastic IAA accumulation and reduced NH4+ efflux under high-NH4+ stress. Furthermore, we show that NH4+ treatment promotes H+ efflux at the root elongation zone, in turn promoting NH4+ efflux, with the involvement of PIN5-mediated intracellular IAA transport. Moreover, stabilization of rhizosphere pH reduced NH4+ efflux and promoted primary root growth in the pin5 mutant under high NH4+.Conclusion Our findings provide a mechanistic explanation for the role of subcellular IAA homeostasis in response to high-NH4+ stress through the coordinated regulation of NH4+ efflux and H+ efflux.

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