The extremophyteEutrema salsugineum(Yukon ecotype) has adapted to an environment low in available phosphate through metabolic and root-associated traits that enables it to efficiently retrieve, use, and recycle phosphorus. Efficient phosphate (Pi) use by plants would increase crop productivity under Pi-limiting conditions and reduce our reliance on Pi applied as fertilizer. An ecotype of Eutrema salsugineum originating from the Yukon, Canada, shows no evidence of decreased relative growth rate or biomass under low Pi conditions and, as such, offers a promising model for identifying mechanisms to improve Pi use by crops. We evaluated traits associated with efficient Pi use by Eutrema (Yukon ecotype) seedlings and 4-week-old plants, including acquisition, remobilization, and the operation of metabolic bypasses. Relative to Arabidopsis, Eutrema was slower to remobilize phosphorus (P) from senescing leaves, primary and lateral roots showed a lower capacity for rhizosphere acidification, and root acid phosphatase activity was more broadly distributed and not Pi responsive. Both species produced long root hairs on low Pi media, whereas Arabidopsis root hairs were well endowed with phosphatase activity. This capacity was largely absent in Eutrema. In contrast to Arabidopsis, maximal in vitro rates of pyrophosphate-dependent phosphofructokinase and phosphoenolpyruvate carboxylase activities were not responsive to low Pi conditions suggesting that Eutrema has a constitutive and likely preferential capacity to use glycolytic bypass enzymes. Rhizosphere acidification, exudation of acid phosphatases, and rapid remobilization of leaf P are unlikely strategies used by Eutrema for coping with low Pi. Rather, equipping an entire root system for Pi acquisition and utilizing a metabolic strategy suited to deficient Pi conditions offer better explanations for how Eutrema has adapted to thrive on alkaline, highly saline soil that is naturally low in available Pi.

中文翻译：

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Eutrema salsuginum 对低磷酸盐条件的耐受性与组成性代谢和根相关适应密切相关的证据

极端植物Eutrema salsugineum（育空生态型）通过代谢和根相关性状适应了可用磷酸盐含量低的环境，使其能够有效地回收、利用和循环磷。植物有效使用磷酸盐 (Pi) 将在 Pi 限制条件下提高作物生产力，并减少我们对作为肥料施用的 Pi 的依赖。来自加拿大育空地区的 Eutrema salsugineum 生态型没有显示出在低磷条件下相对生长速率或生物量下降的证据，因此，为确定提高作物对磷利用的机制提供了一个有前景的模型。我们评估了 Eutrema（育空生态型）幼苗和 4 周龄植物与有效 Pi 使用相关的性状，包括获取、再动员和代谢旁路的操作。相对于拟南芥，Eutrema 对衰老叶片中磷 (P) 的再迁移速度较慢，初生根和侧根对根际酸化的能力较低，根酸性磷酸酶活性分布更广泛，对磷无反应。这两个物种在低 Pi 培养基上都产生了长根毛，而拟南芥的根毛则具有很好的磷酸酶活性。Eutrema 基本上没有这种能力。与拟南芥相比，焦磷酸依赖性磷酸果糖激酶和磷酸烯醇丙酮酸羧化酶活性的最大体外速率对低 Pi 条件没有反应，这表明 Eutrema 具有使用糖酵解旁路酶的组成性和可能的​​优先能力。根际酸化，酸性磷酸酶渗出，Eutrema 不太可能采用叶 P 的快速再活化来应对低 Pi 的策略。相反，为 Pi 获取装备整个根系并利用适合缺乏 Pi 条件的代谢策略为 Eutrema 如何适应在可用 Pi 天然低的碱性、高盐渍土壤上茁壮成长提供了更好的解释。