Most land plants can form symbiosis with arbuscular mycorrhizal (AM) fungi to enhance uptake of mineral nutrients, particularly phosphate (Pi) and nitrogen (N), from the soil. It is established that transport of Pi from interfacial apoplast into plant cells depends on the H+ gradient generated by the H+ -ATPase located on the periarbuscular membrane (PAM); however, little evidence regarding the potential link between mycorrhizal N transport and H+ -ATPase activity is available to date. Here, we report that a PAM-localized tomato H+ -ATPase, SlHA8, is indispensable for arbuscule development and mycorrhizal P and N uptake. Knockout of SlHA8 resulted in truncated arbuscule morphology, reduced shoot P and N accumulation, and decreased H+ -ATPase activity and acidification of apoplastic spaces in arbusculated cells. Overexpression of SlHA8 in tomato promoted both P and N uptake, and increased total colonization level, but did not affect arbuscule morphology. Heterogeneous expression of SlHA8 in the rice osha1 mutant could fully complement its defects in arbuscule development and mycorrhizal P and N uptake. Our results propose a pivotal role of the SlHA8 in energizing both the symbiotic P and N transport, and highlight the evolutionary conservation of the AM-specific H+ -ATPase orthologs in maintaining AM symbiosis across different mycorrhizal plant species.

中文翻译：

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菌根特异的H + -ATPase对丛枝发育以及共生磷酸盐和氮的吸收至关重要。

大多数陆地植物可与丛枝菌根（AM）真菌形成共生关系，以增强土壤中矿质养分的吸收，尤其是磷酸盐（Pi）和氮（N）的吸收。已经确定，Pi从界面质外体进入植物细胞的运输取决于位于周皮膜（PAM）上的H + -ATP酶产生的H +梯度。然而，迄今为止，关于菌根氮转运与H + -ATPase活性之间潜在联系的证据很少。在这里，我们报道一个PAM本地化的番茄H + -ATPase，SlHA8，对于丛枝发育和菌根磷和氮的吸收是必不可少的。SlHA8的敲除导致截短的丛枝形态，减少了芽P和N的积累，并减少了H + -ATPase的活性，并使丛生细胞的质外体空间酸化。番茄中SlHA8的过表达促进了磷和氮的吸收，并增加了总定植水平，但并未影响丛枝的形态。水稻osha1突变体中SlHA8的异质表达可以完全弥补其在丛枝发育和菌根磷和氮吸收中的缺陷。我们的研究结果表明，SlHA8在共生P和N转运中起着关键作用，并突出了AM特异性H + -ATPase直系同源物在不同菌根植物中维持AM共生的进化保守性。