Peptide TRansporters (PTRs) translocate nitrogen (N)-containing substances across cellular membranes. In Arabidopsis thaliana, the seed-abundant, tonoplast-localized AtPTR2 protein is involved in the regulation of water status during seed germination and is negatively regulated by ABA INSENSITIVE4 (ABI4). A survey of publicly available whole-genome sequencing and RNA-seq data revealed that the genomes of hexaploid wheat (Triticum aestivum L.) harbors three homologs of the AtPTR2 gene, TaPTR2.1, TaPTR2.2, and TaPTR2.3, and transcripts of TaPTR2.1 are detected both in dry and germinating seeds, similar to AtPTR2. However, the functional role of TaPTR2.1 during seed germination has not yet been characterized. In the present study, changes in TaPTR2.1 transcript levels were investigated in the wheat cultivar Keumgang in response to phytohormone, sugar, and osmoticum treatments. A transient increase in the transcript level of TaPTR2.1 during seed germination was significantly lowered by abscisic acid (ABA) and PEG4000 treatments. Further, overexpression of the TaPTR2.1 gene under the control of the Cauliflower mosaic virus 35S promoter in the Arabidopsis ptr2 mutant rescued the delayed seed germination phenotype by restoring the seed water status. Together, these results suggest that TaPTR2.1 regulates the water status of wheat seeds during germination in an ABA-dependent manner.

中文翻译：

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小麦种子转运蛋白2.1（TaPTR2.1）在种子萌发过程中的表达。

肽转运蛋白（PTR）将含氮（N）的物质转运穿过细胞膜。在拟南芥中，种子丰富，液泡膜定位的AtPTR2蛋白参与种子萌发过程中水分状态的调节，并受ABA INSENSITIVE4（ABI4）负调节。对公开的全基因组测序和RNA-seq数据进行的一项调查显示，六倍体小麦（Triticum aestivum L.）的基因组具有AtPTR2基因的三个同源物TaPTR2.1，TaPTR2.2和TaPTR2.3，以及转录本的TaPTR2.1在干燥和发芽的种子，类似于检测到两个AtPTR2。但是，尚未鉴定TaPTR2.1在种子发芽过程中的功能作用。在本研究中，研究了小麦品种Keumgang对植物激素，糖和渗透压处理后TaPTR2.1转录水平的变化。脱落酸（ABA）和PEG4000处理显着降低了种子发芽过程中TaPTR2.1转录水平的瞬时增加。此外，拟南芥ptr2中的花椰菜花叶病毒35S启动子控制下TaPTR2.1基因的过表达。突变体通过恢复种子水分状态拯救了延迟的种子发芽表型。总之，这些结果表明TaPTR2.1以ABA依赖性方式调节发芽过程中小麦种子的水分状况。