Sulfur (S) is an essential macronutrient for plant growth and metabolism. SULTR2;1 is a low-affinity sulfate transporter facilitating the long-distance transport of sulfate in Arabidopsis. The physiological function of SULTR2;1 in the plant life cycle still needs to be determined. Therefore, we analyzed the sulfate transport, S-containing metabolites accumulation, and plant growth using Arabidopsis SULTR2;1 disruption lines, sultr2;1-1 and sultr2;1-2, from seedling to mature growth stages to clarify the metabolic and physiological roles of SULTR2;1. We observed that sulfate distribution to the stems was affected in sultr2;1 mutants resulting in decreased levels of sulfate, cysteine, glutathione (GSH), and total S in the stems, flowers, and siliques; however, the GSH levels increased in the rosette leaves. This suggested the essential role of SULTR2;1 in sulfate transport from rosette leaves to the primary stem. In addition, sultr2;1 mutants unexpectedly bolted earlier than the wild-type without affecting the plant biomass. Correlation between GSH levels in rosette leaves and the bolting timing suggested the rosette leaf GSH levels or limited sulfate transport to the early stem can trigger bolting. Overall, this study demonstrated the critical roles of SULTR2;1 in maintaining the S metabolite levels in the aerial part and transitioning from the vegetative to the reproductive growth phase.

中文翻译：

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SULTR2;1 通过将硫酸盐从莲座叶输送到主茎来调整抽苔时间

硫（S）是植物生长和代谢所必需的常量营养素。SULTR2;1 是一种低亲和力硫酸盐转运蛋白，有助于拟南芥中硫酸盐的长距离运输。SULTR2;1在植物生命周期中的生理功能仍需确定。因此，我们利用拟南芥 SULTR2;1 破坏系、sultr2;1-1 和 sultr2;1-2 分析了从幼苗到成熟生长阶段的硫酸盐转运、含硫代谢物积累和植物生长，以阐明代谢和生理作用SULTR2；1。我们观察到，在 sultr2;1 突变体中，硫酸盐在茎上的分布受到影响，导致茎、花和长角果中硫酸盐、半胱氨酸、谷胱甘肽 (GSH) 和总硫的水平降低；然而，莲座叶中的谷胱甘肽水平却有所增加。这表明 SULTR2;1 在硫酸盐从莲座叶到初生茎的转运中发挥重要作用。此外，sultr2;1突变体出乎意料地比野生型更早抽苔，但不影响植物生物量。莲座叶中的 GSH 水平与抽苔时间之间的相关性表明，莲座叶中的 GSH 水平或有限的硫酸盐向早期茎的运输可能会引发抽苔。总体而言，本研究证明了 SULTR2;1 在维持地上部分硫代谢物水平以及从营养生长阶段过渡到生殖生长阶段方面的关键作用。