Land Eric S, Cridland Caitlin A, Craige Branch, Dye Anna, Hildreth Sherry B, Helm Rich F, Gillaspy Glenda E, Perera Imara Y
Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
Department of Biochemistry, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA.
Metabolites. 2021 Sep 4;11(9):601. doi: 10.3390/metabo11090601.
Phosphate is a major plant macronutrient and low phosphate availability severely limits global crop productivity. In , a key regulator of the transcriptional response to low phosphate, phosphate starvation response 1 (PHR1), is modulated by a class of signaling molecules called inositol pyrophosphates (PP-InsPs). Two closely related diphosphoinositol pentakisphosphate enzymes ( and ) are responsible for the synthesis and turnover of InsP, the most implicated molecule. This study is focused on characterizing / double mutants and their response to low phosphate. We present evidence that both local and systemic responses to phosphate limitation are dampened in the / mutants as compared to wild-type plants. Specifically, we demonstrate that under Pi-limiting conditions, the /2 mutants have shorter root hairs and lateral roots, less accumulation of anthocyanin and less accumulation of sulfolipids and galactolipids. However, phosphate starvation response (PSR) gene expression is unaffected. Interestingly, many of these phenotypes are opposite to those exhibited by other mutants with defects in the PP-InsP synthesis pathway. Our results provide insight on the nexus between inositol phosphates and pyrophosphates involved in complex regulatory mechanisms underpinning phosphate homeostasis in plants.
磷是植物的一种主要大量营养素，低磷可用性严重限制了全球作物产量。在植物中，低磷转录反应的关键调节因子磷饥饿反应1（PHR1）受一类称为肌醇焦磷酸（PP-InsPs）的信号分子调控。两种密切相关的二磷酸肌醇五磷酸酶（ 和 ）负责合成和周转最相关的分子InsP。本研究聚焦于对 / 双突变体及其对低磷反应的特性进行表征。我们提供的证据表明，与野生型植物相比， / 突变体对磷限制的局部和系统反应均受到抑制。具体而言，我们证明在低磷条件下， /2突变体的根毛和侧根较短，花青素积累较少，硫脂和半乳糖脂积累较少。然而，磷饥饿反应（PSR）基因表达未受影响。有趣的是，许多这些表型与PP-InsP合成途径有缺陷的其他突变体所表现出的表型相反。我们的结果为参与植物磷稳态复杂调控机制的肌醇磷酸和焦磷酸之间的联系提供了见解。
