Magnesium promotes tea plant growth via enhanced glutamine synthetase-mediated nitrogen assimilation

作者：Qunfeng Zhang, Yutao Shi, Hao Hu, Yuanzhi Shi, Dandan Tang, Jianyun Ruan, Alisdair R. Fernie, Meiya Liu · 发表于：PLANT PHYSIOLOGY · 年份：2023 · DOI：10.1093/plphys/kiad143 · 被引用次数：41 · 研究领域：Plant nutrient uptake and metabolism、Aluminum toxicity and tolerance in plants and animals、Plant Micronutrient Interactions and Effects

Acidic tea (Camellia sinensis) plantation soil usually suffers from magnesium (Mg) deficiency, and as such, application of fertilizer containing Mg can substantially increase tea quality by enhancing the accumulation of nitrogen (N)-containing chemicals such as amino acids in young tea shoots. However, the molecular mechanisms underlying the promoting effects of Mg on N assimilation in tea plants remain unclear. Here, both hydroponic and field experiments were conducted to analyze N, Mg, metabolite contents, and gene expression patterns in tea plants. We found that N and amino acids accumulated in tea plant roots under Mg deficiency, while metabolism of N was enhanced by Mg supplementation, especially under a low N fertilizer regime. 15N tracing experiments demonstrated that assimilation of N was induced in tea roots following Mg application. Furthermore, weighted gene correlation network analysis (WGCNA) analysis of RNA-seq data suggested that genes encoding glutamine synthetase isozymes (CsGSs), key enzymes regulating N assimilation, were markedly regulated by Mg treatment. Overexpression of CsGS1.1 in Arabidopsis (Arabidopsis thaliana) resulted in a more tolerant phenotype under Mg deficiency and increased N assimilation. These results validate our suggestion that Mg transcriptionally regulates CsGS1.1 during the enhanced assimilation of N in tea plant. Moreover, results of a field experiment demonstrated that high Mg and low N had positive effects on tea quality. This stu...