Main conclusion This work reveals information about new peroxisomal targeting signals type 1 and identifies trehalose-6-phosphate phosphatase I as multitargeted and is implicated in plant development, reproduction, and stress response. Abstract A putative, non-canonical peroxisomal targeting signal type 1 (PTS1) Pro-Arg-Met > was identified in the extreme C-terminus of trehalose-6-phosphate phosphatase (TPP)I. TPP catalyzes the final step of trehalose synthesis, and the enzyme was previously characterized to be nuclear only (Krasensky et al. in Antioxid Redox Signal 21(9):1289–1304, 2014). Here we show that the TPPI C-terminal decapeptide ending with Pro-Arg-Met > or Pro-Lys-Met > can indeed function as a PTS1. Upon transient expression in two plant expression systems, the free C- or N-terminal end led to the full-length TPPI targeting to peroxisomes and plastids, respectively. The nucleus and nucleolus targeting of the full-length TPPI was observed in both cases. The homozygous T-DNA insertion line of TPPI showed a pleiotropic phenotype including smaller leaves, shorter roots, delayed flowering, hypersensitivity to salt, and a sucrose dependent seedling development. Our results identify novel PTS1s, and TPPI as a protein multi-targeted to peroxisomes, plastids, nucleus, and nucleolus. Altogether our findings implicate an essential role for TPPI in development, reproduction, and cell signaling.

中文翻译：

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多靶点海藻糖-6-磷酸磷酸酶 I 具有新的过氧化物酶体靶向信号 1，对开花和发育至关重要

主要结 摘要 在海藻糖-6-磷酸磷酸酶 (TPP)I 的极端 C 末端鉴定了一种推定的、非经典的过氧化物酶体靶向信号 1 (PTS1) Pro-Arg-Met >。TPP 催化海藻糖合成的最后一步，该酶以前被表征为仅核酶（Krasensky 等人在 Antioxid Redox Signal 21(9):1289–1304, 2014）。在这里，我们表明以 Pro-Arg-Met > 或 Pro-Lys-Met > 结尾的 TPPI C 末端十肽确实可以作为 PTS1 发挥作用。在两种植物表达系统中瞬时表达后，游离的 C 或 N 末端导致全长 TPPI 分别靶向过氧化物酶体和质体。在两种情况下都观察到全长 TPPI 的核和核仁靶向。TPPI的纯合T-DNA插入系表现出多效性表型，包括小叶、短根、延迟开花、对盐过敏和依赖蔗糖的幼苗发育。我们的研究结果确定了新的 PTS1 和 TPPI 作为一种多靶向过氧化物酶体、质体、细胞核和核仁的蛋白质。总之，我们的研究结果表明 TPPI 在发育、繁殖和细胞信号传导中的重要作用。TPPI的纯合T-DNA插入系表现出多效性表型，包括小叶、短根、延迟开花、对盐过敏和依赖蔗糖的幼苗发育。我们的研究结果确定了新的 PTS1 和 TPPI 作为一种多靶向过氧化物酶体、质体、细胞核和核仁的蛋白质。总之，我们的研究结果表明 TPPI 在发育、繁殖和细胞信号传导中的重要作用。TPPI的纯合T-DNA插入系表现出多效性表型，包括小叶、短根、延迟开花、对盐过敏和依赖蔗糖的幼苗发育。我们的研究结果确定了新的 PTS1 和 TPPI 作为一种多靶向过氧化物酶体、质体、细胞核和核仁的蛋白质。总之，我们的研究结果表明 TPPI 在发育、繁殖和细胞信号传导中的重要作用。