As an essential macronutrient, phosphorus (P) is often a limiting nutrient because of its low availability and mobility in soils. Drought is a major environmental stress that reduces crop yield. How plants balance and combine P-starvation responses (PSRs) and drought resistance is unclear. In this study, we identified the transcription factor ZmPHR1 as a major regulator of PSRs that modulates phosphate (Pi) signaling and homeostasis. We found that maize zmphr1 mutants had reduced P concentration and were sensitive to Pi starvation, whereas ZmPHR1-OE lines displayed elevated Pi concentration and yields. In addition, 57% of PSR genes and nearly 70% of ZmPHR1-regulated PSR genes in leaves were transcriptionally responsive to drought. Under moderate and early drought conditions, the Pi concentration of maize decreased, and PSR genes were up-regulated before drought-responsive genes. The ZmPHR1-OE lines exhibited drought-resistant phenotypes and reduced stomatal apertures, whereas the opposite was true of the zmphr1 mutants. ZmPT7-OE lines and zmspx3 mutants, which had elevated Pi concentration, also exhibited drought resistance, but zmpt7 mutants were sensitive to drought. Our results suggest that ZmPHR1 plays a central role in integrating Pi and drought signals and that Pi homeostasis improves the ability of maize to combat drought.

中文翻译：

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ZmPHR1 通过调节玉米磷酸盐稳态有助于抗旱


作为一种必需的常量营养素，磷 (P) 通常是一种限制性营养素，因为它在土壤中的利用率和流动性较低。干旱是导致作物产量降低的主要环境压力。植物如何平衡和结合磷饥饿反应（PSR）和抗旱性尚不清楚。在这项研究中，我们确定转录因子 ZmPHR1 是 PSR 的主要调节因子，可调节磷酸盐 (Pi) 信号传导和稳态。我们发现玉米 zmphr1 突变体的磷浓度降低，并且对磷饥饿敏感，而 ZmPHR1-OE 品系则显示磷浓度和产量升高。此外，叶片中57%的PSR基因和近70%的ZmPH​​R1调控的PSR基因在转录上对干旱有反应。中、早干旱条件下，玉米Pi浓度下降，PSR基因先于干旱响应基因上调。 ZmPHR1-OE 品系表现出抗旱表型和气孔孔径减小，而 zmphr1 突变体则相反。 Pi浓度升高的ZmPT7-OE品系和zmspx3突变体也表现出抗旱性，但zmpt7突变体对干旱敏感。我们的结果表明，ZmPHR1 在整合 Pi 和干旱信号方面发挥着核心作用，并且 Pi 稳态提高了玉米抵抗干旱的能力。