Soil and Plant Microbiology Department, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.
Institut des Sciences des Plantes de Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique, Institut Agro Montpellier, Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement, Montpellier, France.
Environ Pollut. 2024 Jan 15;341:122990. doi: 10.1016/j.envpol.2023.122990. Epub 2023 Nov 20.
Arbuscular mycorrhizal (AM) fungi establish a mutualistic symbiosis with most land plants. AM fungi regulate plant copper (Cu) acquisition both in Cu deficient and polluted soils. Here, we report characterization of RiCRD1, a Rhizophagus irregularis gene putatively encoding a Cu transporting ATPase. Based on its sequence analysis, RiCRD1 was identified as a plasma membrane Cu efflux protein of the P-ATPase subfamily. As revealed by heterologous complementation assays in yeast, RiCRD1 encodes a functional protein capable of conferring increased tolerance against Cu. In the extraradical mycelium, RiCRD1 expression was highly up-regulated in response to high concentrations of Cu in the medium. Comparison of the expression patterns of different players of metal tolerance in R. irregularis under high Cu levels suggests that this fungus could mainly use a metal efflux based-strategy to cope with Cu toxicity. RiCRD1 was also expressed in the intraradical fungal structures and, more specifically, in the arbuscules, which suggests a role for RiCRD1 in Cu release from the fungus to the symbiotic interface. Overall, our results show that RiCRD1 encodes a protein which could have a pivotal dual role in Cu homeostasis in R. irregularis, playing a role in Cu detoxification in the extraradical mycelium and in Cu transfer to the apoplast of the symbiotic interface in the arbuscules.
丛枝菌根 (AM) 真菌与大多数陆生植物建立互利共生关系。AM 真菌在 Cu 缺乏和污染土壤中调节植物 Cu 的吸收。在这里，我们报道了 RiCRD1 的特征，RiCRD1 是 Rhizophagus irregularis 中一个假定编码 Cu 转运 ATP 酶的基因。基于其序列分析，RiCRD1 被鉴定为 P-ATPase 亚家族的质膜 Cu 外排蛋白。酵母中的异源互补测定表明，RiCRD1 编码一种能够赋予对 Cu 更高耐受性的功能蛋白。在根外菌丝中，RiCRD1 的表达在培养基中 Cu 浓度高时高度上调。在高 Cu 水平下对 R. irregularis 中不同金属耐受性参与者的表达模式进行比较表明，该真菌主要可能使用金属外排策略来应对 Cu 毒性。RiCRD1 也在根内真菌结构中表达，特别是在丛枝中，这表明 RiCRD1 在从真菌向共生界面释放 Cu 中发挥作用。总的来说，我们的结果表明，RiCRD1 编码的蛋白质可能在 R. irregularis 中的 Cu 稳态中发挥关键的双重作用，在根外菌丝中的 Cu 解毒和在丛枝中向共生界面质外体的 Cu 转移中发挥作用。
