The drive toward more sustainable agriculture has raised the profile of crop plant nutrient-use efficiency. Here we show that a major rice nitrogen-use efficiency quantitative trait locus (qNGR9) is synonymous with the previously identified gene DEP1 (DENSE AND ERECT PANICLES 1). The different DEP1 alleles confer different nitrogen responses, and genetic diversity analysis suggests that DEP1 has been subjected to artificial selection during Oryza sativa spp. japonica rice domestication. The plants carrying the dominant dep1-1 allele exhibit nitrogen-insensitive vegetative growth coupled with increased nitrogen uptake and assimilation, resulting in improved harvest index and grain yield at moderate levels of nitrogen fertilization. The DEP1 protein interacts in vivo with both the Gα (RGA1) and Gβ (RGB1) subunits, and reduced RGA1 or enhanced RGB1 activity inhibits nitrogen responses. We conclude that the plant G protein complex regulates nitrogen signaling and modulation of heterotrimeric G protein activity provides a strategy for environmentally sustainable increases in rice grain yield.
可持续农业对作物的氮利用效率的要求不断提高。本研究报道了一个影响水稻氮利用效率的主效数量性状位点，qNGR9，与之前报道的DEP1是同一个基因(DENSE AND ERECT PANICLES 1)。不同的DEP1等位基因表现出不同的氮应答，遗传多样性分析表明DEP1在粳稻驯化过程中受到了人工选择。带有显性dep1-1的植株表现出氮不敏感型营养生长，以及氮吸收和同化作用增加，导致收获指数和谷粒产量在适度的氮肥条件下能够增加。DEP1蛋白能够在体内与Gα(RGA1) 和 Gβ (RGB1)亚基互作，RGA1活性减低和RGB1活性升高会抑制氮应答。本研究表明植物G蛋白复合体能够调控氮信号，通过调节异源三聚体G蛋白复合体的活性提供了基于环境可持续性增加水稻谷粒产量的新途径。