The synthesis of seed storage protein (SSP) is mainly regulated at the transcriptional level. However, few transcriptional regulators of SSP synthesis have been characterized in common wheat (Triticum aestivum) owing to the complex genome. As the A genome donor of common wheat, Triticum urartu could be an elite model in wheat research considering its simple genome. Here, a novel NAC family transcription factor TuSPR from T. urartu was found preferentially expressed in developing endosperm during grain-filling stages. In common wheat transgenically overexpressing TuSPR, the content of total SSPs was reduced by c. 15.97% attributed to the transcription declines of SSP genes. Both in vitro and in vivo assays showed that TuSPR bound to the cis-element 5′-CANNTG-3′ distributed in SSP gene promoters and suppressed the transcription. The homolog in common wheat TaSPR shared a conserved function with TuSPR on SSP synthesis suppression. The knock-down of TaSPR in common wheat resulted in 7.07%–20.34% increases in the total SSPs. Both TuSPR and TaSPR could be superior targets in genetic engineering to manipulate SSP content in wheat, and this work undoubtedly expands our knowledge of SSP gene regulation.

中文翻译：

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新型NAC家族转录因子SPR抑制小麦种子贮藏蛋白的合成。

种子贮藏蛋白（SSP）的合成主要在转录水平上受到调控。然而，由于基因组复杂，在普通小麦（普通小麦）中很少有SSP合成的转录调节子被表征。作为普通小麦的A基因组供体，考虑到其简单的基因组，Triticum urartu可能是小麦研究中的精英模型。在这里，发现了一种新的NAC家族转录因子来自乌拉尔木霉的TuSPR，在籽粒充实阶段优先在发育中的胚乳中表达。在转基因高表达TuSPR的普通小麦中，总SSPs的含量降低了c。15.97％归因于SSP基因的转录下降。两个都体外和体内试验表明，TuSPR与分布在SSP基因启动子中的顺式5'-CANNTG-3'结合并抑制了转录。普通小麦TaSPR的同系物与TuSPR在SSP合成抑制上具有保守的功能。普通小麦中TaSPR的降低导致SSP总量增加7.07％–20.34％。无论TuSPR和TaSPR可能是基因工程的卓越目标，以操纵小麦SSP内容，这项工作无疑扩展了我们的SSP基因调控的知识。