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.
可持續(xù)農(nóng)業(yè)對(duì)作物的氮利用效率的要求不斷提高。本研究報(bào)道了一個(gè)影響水稻氮利用效率的主效數(shù)量性狀位點(diǎn)，qNGR9，與之前報(bào)道的DEP1是同一個(gè)基因(DENSE AND ERECT PANICLES 1)。不同的DEP1等位基因表現(xiàn)出不同的氮應(yīng)答，遺傳多樣性分析表明DEP1在粳稻馴化過程中受到了人工選擇。帶有顯性dep1-1的植株表現(xiàn)出氮不敏感型營養(yǎng)生長，以及氮吸收和同化作用增加，導(dǎo)致收獲指數(shù)和谷粒產(chǎn)量在適度的氮肥條件下能夠增加。DEP1蛋白能夠在體內(nèi)與Gα(RGA1) 和 Gβ (RGB1)亞基互作，RGA1活性減低和RGB1活性升高會(huì)抑制氮應(yīng)答。本研究表明植物G蛋白復(fù)合體能夠調(diào)控氮信號(hào)，通過調(diào)節(jié)異源三聚體G蛋白復(fù)合體的活性提供了基于環(huán)境可持續(xù)性增加水稻谷粒產(chǎn)量的新途徑。