Reversible phosphorylation is an essential mechanism regulating signal transduction during development and environmental stress responses. An important number of dephosphorylation events in the cell are catalyzed by type one protein phosphatases (PP1), which catalytic activity is driven by the binding of regulatory proteins that control their substrate specificity or subcellular localization. Plants harbor several PP1 isoforms accounting for large functional redundancies. While animal PP1s were reported to play relevant roles in controlling multiple cellular processes, plant orthologs remain poorly studied. To decipher the role of plant PP1s, we compared PP1 genes from three monocot species, Brachypodium, common wheat and rice at the genomic and transcriptomic levels. To gain more insight into the wheat PP1 proteins, we identified and characterized TdPP1a, the first wheat type one protein phosphatase from a Tunisian durum wheat variety Oum Rabiaa3. TdPP1a is highly conserved in sequence and structure when compared to mammalian, yeast and other plant PP1s. We demonstrate that TdPP1a is an active, metallo-dependent phosphatase in vitro and is able to interact with AtI2, a typical regulator of PP1 functions. Also, TdPP1a is capable to complement the heat stress sensitivity of the yeast mutant indicating that TdPP1a is functional also in vivo. Moreover, transient expression of TdPP1a::GFP in tobacco leaves revealed that it is ubiquitously distributed within the cell, with a strong accumulation in the nucleus. Finally, transcriptional analyses showed similar expression levels in roots and leaves of durum wheat seedlings. Interestingly, the expression in leaves is significantly induced following salinity stress, suggesting a potential role of TdPP1a in wheat salt stress response.

可逆的磷酸化是调节发育和环境应激反应过程中信号转导的重要机制。细胞中大量的去磷酸化事件被一型蛋白磷酸酶（PP1）催化，该催化活性由调节蛋白的结合来驱动，这些蛋白控制其底物特异性或亚细胞定位。植物带有几个PP1亚型，说明功能上的大量冗余。虽然据报道动物PP1在控制多个细胞过程中起着相关作用，但植物直系同源物的研究仍很少。为了解释植物PP1的作用，我们比较了PP1基因组和转录组水平上来自三个单子叶植物物种，短枝孢子，普通小麦和水稻的基因。为了更深入地了解小麦PP1蛋白，我们鉴定并鉴定了TdPP1a，这是突尼斯硬质小麦品种Oum Rabiaa3的第一个小麦一型蛋白磷酸酶。与哺乳动物，酵母和其他植物PP1s相比，TdPP1a在序列和结构上高度保守。我们证明了TdPP1a是一种活跃的，依赖金属的磷酸酶在体外，并能够与AtI2，PP1功能的典型调节剂进行交互。此外，TdPP1a能够补充酵母突变体的热应激敏感性，表明TdPP1a在体内也具有功能。此外，TdPP1a :: GFP在烟叶中的瞬时表达表明它普遍存在于细胞内，在细胞核中有很强的积累。最后，转录分析显示硬粒小麦幼苗的根和叶中的表达水平相似。有趣的是，盐分胁迫后叶片中的表达被显着诱导，表明TdPP1a在小麦盐胁迫响应中的潜在作用。