Nitrogen (N) is indispensable for crop growth and yield, but excessive agricultural application of nitrogenous fertilizers has generated severe environmental problems. A desirable and economical solution to cope with these issues is to improve crop nitrogen use efficiency (NUE). Plant NUE has been a focal point of intensive research worldwide, yet much still has to be learned about its genetic determinants and regulation. Here, we show that rice (Oryza sativa L.) NIN-LIKE PROTEIN 1 (OsNLP1) plays a fundamental role in N utilization. OsNLP1 protein localizes in the nucleus and its transcript level is rapidly induced by N starvation. Overexpression of OsNLP1 improves plant growth, grain yield, and NUE under different N conditions, while knockout of OsNLP1 impairs grain yield and NUE under N-limiting conditions. OsNLP1 regulates nitrate and ammonium utilization by cooperatively orchestrating multiple N uptake and assimilation genes. Chromatin immunoprecipitation and yeast one-hybrid assays showed that OsNLP1 can directly bind to the promoter of these genes to activate their expression. Therefore, our results demonstrate that OsNLP1 is a key regulator of N utilization and represents a potential target for improving NUE and yield in rice.

中文翻译：

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水稻NIN-LIKE蛋白1快速响应氮缺乏症，提高了产量和氮的利用效率。

氮（N）对于作物的生长和产量必不可少，但是氮肥在农业上的过度使用已引起严重的环境问题。解决这些问题的理想且经济的解决方案是提高作物氮的利用效率（NUE）。植物NUE一直是全球范围内深入研究的重点，但关于其遗传决定因素和调控的许多知识仍需学习。在这里，我们表明水稻（Oryza sativa L.）NIN-LIKE蛋白1（OsNLP1）在氮利用中起着基本作用。OsNLP1蛋白位于细胞核中，其转录水平被N饥饿迅速诱导。OsNLP1的过表达在不同的氮条件下，可改善植物的生长，籽粒产量和NUE，而敲除OsNLP1会在氮限制条件下损害籽粒产量和NUE。OsNLP1通过协同编排多个氮吸收和同化基因来调节硝酸盐和铵的利用。染色质免疫沉淀和酵母一杂交实验表明，OsNLP1可以直接与这些基因的启动子结合以激活其表达。因此，我们的结果表明，OsNLP1是氮素利用的关键调节剂，是提高水稻NUE和产量的潜在目标。