NH4+ is not only the primary nitrogen for rice, a well-known NH4+ specialist, but is also the chief limiting factor for its production. Limiting NH4+ triggers a series of physiological and biochemical responses that help rice optimise its nitrogen acquisition. However, the dynamic nature and spatial distribution of the adjustments at the whole plant level during this response are still unknown. Here, nitrogen-starved rice seedlings were treated with 0.1 mM (NH4)2SO4 for 4 or 12 h, and then the shoots and roots were harvested for RNA-Seq analysis. We identified 138 and 815 differentially expressed genes (DEGs) in shoots, and 597 and 1074 in roots following 4 and 12 h treatment, respectively. Up-regulated DEGs mainly participated in phenylpropanoid, sugar, and amino acid metabolism, which was confirmed by chemical content analysis. The transcription factor OsJAZ9 was the most pronouncedly induced component under low NH4+ in roots, and a significant increase in root growth, NH4+ absorption, amino acid, and sugar metabolism in response to resupplied NH4+ following nitrogen starvation was identified in JAZ9ox (OsJAZ9-overexpressed) and coi1 (OsCOI1-RNAi). Our data provide comprehensive insight into the whole-plant transcriptomic response in terms of metabolic processes and signaling transduction to a low-NH4+ signal, and identify the transcription factor OsJAZ9 and its involvement in the regulation of carbon/nitrogen metabolism as central to the response to low NH4+.

中文翻译：

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水稻（Oryza sativa L.）响应铵补给的转录组分析揭示了植物激素信号传导和转录因子 OsJAZ9 参与氮吸收和代谢重编程

NH4+不仅是水稻的主要氮元素，是著名的NH4+专家，也是水稻生产的主要限制因素。限制 NH4+ 会触发一系列生理和生化反应，帮助水稻优化其氮的获取。然而，在此响应期间全厂水平调整的动态性质和空间分布仍然未知。在这里，缺氮水稻幼苗用 0.1 mM (NH4)2SO4 处理 4 或 12 小时，然后收获芽和根用于 RNA-Seq 分析。在处理 4 小时和 12 小时后，我们分别在芽中鉴定出 138 和 815 个差异表达基因（DEG），在根中鉴定出 597 和 1074 个差异表达基因。上调的DEGs主要参与苯丙烷、糖和氨基酸代谢，化学含量分析证实了这一点。在低 NH4+ 条件下，转录因子 OsJAZ9 是根中最显着的诱导成分，在 JAZ9ox（OsJAZ9 过表达）中发现，根系生长、NH4+ 吸收、氨基酸和糖代谢显着增加，以响应氮饥饿后补充的 NH4+和 coi1 (OsCOI1-RNAi)。我们的数据在代谢过程和信号转导到低 NH4+ 信号方面提供了对全植物转录组反应的全面洞察，并确定了转录因子 OsJAZ9 及其在碳/氮代谢调节中的参与作为响应的核心低 NH4+。在 JAZ9ox (OsJAZ9 过表达) 和 coi1 (OsCOI1-RNAi) 中鉴定了氮饥饿后对重新供应的 NH4+ 做出反应的糖代谢。我们的数据在代谢过程和信号转导到低 NH4+ 信号方面提供了对全植物转录组反应的全面洞察，并确定了转录因子 OsJAZ9 及其在碳/氮代谢调节中的参与作为响应的核心低 NH4+。在 JAZ9ox (OsJAZ9 过表达) 和 coi1 (OsCOI1-RNAi) 中鉴定了氮饥饿后对重新供应的 NH4+ 做出反应的糖代谢。我们的数据在代谢过程和信号转导到低 NH4+ 信号方面提供了对全植物转录组反应的全面洞察，并确定了转录因子 OsJAZ9 及其在碳/氮代谢调节中的参与作为响应的核心低 NH4+。