籽粒蛋白质含量(GPC)是面包小麦的重要品质性状,受关键转录因子TaNAM的影响。然而,TaNAM的监管机制在很大程度上仍然难以捉摸。在这项研究中,TaNAM在调节影响GPC的氮再动员方面发挥了新作用。由成簇的规则间隔的短回文重复序列/Cas9产生的TaNAM敲除突变体表现出显著延迟的衰老和较低的GPC,而TaNAM-6A的过表达导致早衰和更高的GPC。进一步分析表明,TaNAM直接激活TaNRT1.1和TaNPF5.5s基因,参与氮的再动员。该活性有助于将氮从叶子转移到谷物以进行蛋白质合成。此外,TaNAM-6A的精英等位基因,与高GPC相关,被确定为优质小麦育种的候选基因。总的来说,我们的工作不仅阐明了TaNAM-6A影响面包小麦GPC的潜在机制,但也强调了从衰老叶片到谷物的氮再动员对蛋白质积累的重要性。此外,本研究为小麦品质性状的改良提供了新的目标和途径,特别是GPC。
Grain protein content (
GPC) is a crucial quality trait in bread wheat, which is influenced by the key transcription factor TaNAM. However, the regulatory mechanisms of TaNAM have remained largely elusive. In this study, a new role of TaNAM was unveiled in regulating nitrogen remobilisation which impacts
GPC. The TaNAM knockout mutants generated by clustered regularly interspaced short palindromic repeats/Cas9 exhibited significantly delayed senescence and lower GPC, while overexpression of TaNAM-6A resulted in premature senility and much higher
GPC. Further analysis revealed that TaNAM directly activates the genes TaNRT1.1 and TaNPF5.5s, which are involved in nitrogen remobilisation. This activity aids in the transfer of nitrogen from leaves to grains for protein synthesis. In addition, an elite allele of TaNAM-6A, associated with high
GPC, was identified as a candidate gene for breeding high-quality wheat. Overall, our work not only elucidates the potential mechanism of TaNAM-6A affecting bread wheat
GPC, but also highlights the significance of nitrogen remobilisation from senescent leaves to grains for protein accumulation. Moreover, our research provides a new target and approach for improving the quality traits of wheat, particularly the GPC.