谷氨酰胺合成酶 GhGLN1.5 通过调节无机氮同化来调节棉花丛枝菌根共生和黄萎病抗性
New Phytologist ( IF 8.3 ) Pub Date : 2025-02-25 , DOI: 10.1111/nph.70035
Xiangyu Zhang 1 , Jingshang Wen 1 , Shuangjie Jia 1 , Yiming He 1 , Wan Yang 1 , Wenbo Chen 1 , Dongxiao Li 1 , Ruojun Liu 1 , Qian Liu 1 , Yingfan Cai 1 , Kai Cheng 1 , Xiao Zhang 1, 2
丛枝菌根 （AM） 真菌在棉花的氮吸收和黄萎病抗性中起着至关重要的作用。吸收的无机氮通过谷氨酰胺合成酶 （GS） 介导的氮同化转化为有机氮。然而，GS 在 AM 共生和黄萎病抗性中的作用仍不清楚。
我们确定了一个 AM 真菌诱导的 GS 基因 GhGLN1.5，它参与了 AM 共生。体内和体外分析均表明 GhGLN1.5 具有 GS 的催化活性。
敲除 GhGLN1.5 导致 AM 定植、氮摄取能力和 AM 共生依赖性对黄萎病的耐药性降低。GhGLN1.5 的异源表达增强了 AM 共生，增加了 GS 活性，并促进了植物生长。棉花中 GhGLN1.5 的敲除抑制了 AM 共生。此外，我们通过酵母单杂交文库筛选鉴定了一个 AM 真菌诱导的乙烯反应因子基因 GhWRI3，发现 GhWRI3 通过 AW-box 元件激活 GhGLN1.5 的表达。
这些发现为 GhGLN1.5 在棉花 AM 共生、氮同化和黄萎病抗性中的分子机制提供了有价值的见解，提出了通过 WRI3-GLN1.5 模块调节棉花 AM 共生的潜在策略。
Glutamine synthetase GhGLN1.5 regulates arbuscular mycorrhizal symbiosis and Verticillium wilt resistance in cotton by modulating inorganic nitrogen assimilation
- Arbuscular mycorrhizal (AM) fungi play a crucial role in the nitrogen uptake and Verticillium wilt resistance of cotton. The absorbed inorganic nitrogen is converted into organic nitrogen through nitrogen assimilation mediated by glutamine synthetase (GS). However, the role of GS in AM symbiosis and Verticillium wilt resistance remains unclear.
- We identified an AM fungus-induced GS gene, GhGLN1.5, which participated in AM symbiosis. Both in vivo and in vitro analyses demonstrated that GhGLN1.5 exhibits catalytic activity of GS.
- The knockdown of GhGLN1.5 resulted in a reduction of AM colonization, nitrogen uptake capacity, and AM symbiosis-dependent resistance to Verticillium wilt. Heterologous expression of GhGLN1.5 enhanced AM symbiosis, increased GS activity, and promoted plant growth. The knockout of GhGLN1.5 in cotton inhibited AM symbiosis. Furthermore, we identified an AM fungus-induced ethylene response factor gene GhWRI3 through yeast one-hybrid library screening and found that GhWRI3 activates the expression of GhGLN1.5 via AW-box element.
- These findings provide valuable insights into the molecular mechanisms of GhGLN1.5 expression in AM symbiosis, nitrogen assimilation, and Verticillium wilt resistance in cotton, suggesting potential strategies for regulating AM symbiosis in cotton through the WRI3–GLN1.5 module.
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