A SPX domain-containing phosphate transporter from Rhizophagus irregularis handles phosphate homeostasis at symbiotic interface of arbuscular mycorrhizas
A SPX domain-containing phosphate transporter from Rhizophagus irregularis handles phosphate homeostasis at symbiotic interface of arbuscular mycorrhizas
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来自不规则根瘤菌的含有 SPX 结构域的磷酸盐转运蛋白处理丛枝菌根共生界面的磷酸盐稳态
DOI：
10.1111/nph.17973
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发表时间：
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期刊：
影响因子：
9.4
通讯作者：
Ming Tang
中科院分区：
文献类型：
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作者：
Xianan Xie;Wenzhen Lai;Xianrong Che;Sijia Wang;Ying Ren;Wentao Hu;Hui Chen;Ming Tang
> 70% 的陆生维管束植物与丛枝菌根 (AM) 真菌相互共生，为真菌提供脂肪酸和糖。作为回报，AM 真菌促进植物从土壤中吸收磷酸盐 (Pi)。然而，AM 真菌如何在 AM 共生界面处理 Pi 转运和稳态尚不清楚。在这里，我们从不规则根噬菌中鉴定出一种包含 SPX (SYG1/Pho81/XPR1) 结构域的磷酸盐转运蛋白 RiPT7。为了表征 RiPT7 转运蛋白，我们将酵母中的亚细胞定位和异源表达研究与植物前期的反向遗传学方法相结合。结果表明，RiPT7 在真菌物种中是保守的，并在根内菌丝体中表达。它在丛枝、根内菌丝和囊泡中表达，与 Pi 的可用性无关。质膜定位的 RiPT7 促进 Pi 的双向转运，具体取决于质膜上的 Pi 梯度，而 RiPT7 的 SPX 结构域抑制 Pi 转运活性并介导 RiPT7 在酵母中响应 Pi 饥饿的液泡靶向。重要的是，RiPT7 沉默阻碍了 R 的丛枝发育。 中低 Pi 条件下的不规则和共生 Pi 传递。总的来说，我们的研究结果揭示了 RiPT7 在微调整个真菌膜 Pi 稳态以维持 AM 发育中的作用。
Reciprocal symbiosis of > 70% of terrestrial vascular plants with arbuscular mycorrhizal (AM) fungi provides the fungi with fatty acids and sugars. In return, AM fungi facilitate plant phosphate (Pi) uptake from soil. However, how AM fungi handle Pi transport and homeostasis at the symbiotic interface of AM symbiosis is poorly understood.Here, we identify an SPX (SYG1/Pho81/XPR1) domain‐containing phosphate transporter, RiPT7 fromRhizophagus irregularis. To characterize the RiPT7 transporter, we combined subcellular localization and heterologous expression studies in yeasts with reverse genetics approaches during thein plantaphase.The results show thatRiPT7is conserved across fungal species and expressed in the intraradical mycelia. It is expressed in the arbuscules, intraradical hyphae and vesicles, independently of Pi availability. The plasma membrane‐localized RiPT7 facilitates bidirectional Pi transport, depending on Pi gradient across the plasma membrane, whereas the SPX domain of RiPT7 inhibits Pi transport activity and mediates the vacuolar targeting of RiPT7 in yeast in response to Pi starvation. Importantly,RiPT7silencing hampers arbuscule development ofR. irregularisand symbiotic Pi delivery under medium‐ to low‐Pi conditions.Collectively, our findings reveal a role for RiPT7 in fine‐tuning of Pi homeostasis across the fungal membrane to maintain the AM development.