Forest Botany and Tree Physiology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany; Laboratory for Radio-Isotopes, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
Molecular Wood Biotechnology and Technical Mycology, University of Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
Plant Sci. 2021 Jun;307:110906. doi: 10.1016/j.plantsci.2021.110906. Epub 2021 Apr 6.
Plants secrete purple acid phosphatases (PAPs) under phosphorus (P) shortage but the contribution of plant PAPs to P acquisition is not well understood. The goals of this study were to investigate comprehensively the transcription patterns of PAPs under P shortage in poplar (Populus × canescens), to identify secreted PAPs and to characterize their contribution to mobilize organic P. Phylogenetic analyses of the PAP family revealed 33 putative members. In this study, distinct, tissue-specific P responsive expression patterns could be shown for 23 PAPs in roots and leaves. Root-associated PAP activities were localized on the root surface by in-vivo staining. The activities of root-surface PAPs increased significantly under low P availability, but were suppressed by a PAP inhibitor and corresponded to elevated P uptake from ATP as an organic P source. By proteomic analyses of the root apoplast, we identified three newly secreted proteins under P shortage: PtPAP1 (Potri.005G233400) and two proteins with unknown functions (Potri.013G100800 and Potri.001G209300). Our results, based on the combination of transcriptome and proteome analyses with phosphatase activity assays, support that PtPAP1 plays a central role in enhanced P acquisition from organic sources, when the phosphate concentrations in soil are limited.
在磷（P）缺乏的情况下，植物会分泌紫色酸性磷酸酶（PAPs），但植物 PAPs 对 P 吸收的贡献尚不清楚。本研究的目的是全面研究杨树（Populus × canescens）在 P 缺乏下 PAPs 的转录模式，鉴定分泌的 PAPs，并表征它们对动员有机 P 的贡献。PAP 家族的系统发育分析显示出 33 个假定的成员。在这项研究中，在根和叶中可以显示出 23 个 PAP 对 P 响应的不同、组织特异性表达模式。通过体内染色，在根表面定位到与根相关的 PAP 活性。在低 P 供应下，根表面 PAP 活性显著增加，但被 PAP 抑制剂抑制，并与从 ATP 作为有机 P 源吸收增加的 P 相对应。通过对根质外体的蛋白质组学分析，我们在 P 缺乏下鉴定了三种新分泌的蛋白质：PtPAP1（Potri.005G233400）和两种具有未知功能的蛋白质（Potri.013G100800 和 Potri.001G209300）。基于转录组和蛋白质组分析与磷酸酶活性测定的结合，我们的研究结果表明，当土壤中的磷酸盐浓度有限时，PtPAP1 在增强从有机来源获取 P 方面发挥着核心作用。
