National Key Laboratory of Wheat Breeding, Shandong Agricultural University, Taian, Shandong, 271018, China.
College of Life Sciences, Shandong Agricultural University, Taian, Shandong, 271018, China.
BMC Plant Biol. 2024 Jan 2;24(1):1. doi: 10.1186/s12870-023-04695-w.
Wheat is one of the main grain crops in the world, and the tiller number is a key factor affecting the yield of wheat. Phosphorus is an essential element for tiller development in wheat. However, due to decreasing phosphorus content in soil, there has been increasing use of phosphorus fertilizer, while imposing risk of soil and water pollution. Hence, it is important to identify low phosphorus tolerance genes and utilize them for stress resistance breeding in wheat.
We subjected the wheat variety Kenong 199 (KN199) to low phosphorus stress and observed a reduced tiller number. Using transcriptome analysis, we identified 1651 upregulated genes and 827 downregulated of genes after low phosphorus stress. The differentially expressed genes were found to be enriched in the enzyme activity regulation related to phosphorus, hormone signal transduction, and ion transmembrane transport. Furthermore, the transcription factor analysis revealed that TaWRKY74s were important for low phosphorus tolerance. TaWRKY74s have three alleles: TaWRKY74-A, TaWRKY74-B, and TaWRKY74-D, and they all belong to the WRKY family with conserved WRKYGQK motifs. These proteins were found to be located in the nucleus, and they were expressed in axillary meristem, shoot apical meristem(SAM), young leaves, leaf primordium, and spikelet primordium. The evolutionary tree showed that TaWRKY74s were closely related to OsWRKY74s in rice. Moreover, TaWRKY74s-RNAi transgenic plants displayed significantly fewer tillers compared to wild-type plants under normal conditions. Additionally, the tiller numebr of the RNAi transgenic plants was also significantly lower than that of the wild-type plants under low-phosphorus stress, and increased the decrease amplitude. This suggestd that TaWRKY74s are related to phosphorus response and can affect the tiller number of wheat.
The results of this research showed that TaWRKY74s were key genes in wheat response to low phosphorus stress, which might regulate wheat tiller number through abscisic acid (ABA) and auxin signal transduction pathways. This research lays the foundation for further investigating the mechanism of TaWRKY74s in the low phosphorus environments and is significant for wheat stress resistance breeding.
小麦是世界上主要的粮食作物之一，分蘖数是影响小麦产量的关键因素。磷是小麦分蘖发育的必需元素。然而，由于土壤中磷含量的减少，人们越来越多地使用磷肥，同时也带来了土壤和水污染的风险。因此，鉴定低磷耐性基因并将其用于小麦的抗逆性育种非常重要。
我们对小麦品种 Kenong 199（KN199）进行了低磷胁迫处理，观察到分蘖数减少。通过转录组分析，我们在低磷胁迫后鉴定出 1651 个上调基因和 827 个下调基因。差异表达基因富集在与磷相关的酶活性调节、激素信号转导和离子跨膜运输中。此外，转录因子分析表明 TaWRKY74s 对低磷胁迫有重要作用。TaWRKY74s 有三个等位基因：TaWRKY74-A、TaWRKY74-B 和 TaWRKY74-D，它们都属于 WRKY 家族，具有保守的 WRKYGQK 基序。这些蛋白被发现位于细胞核内，在腋芽分生组织、茎尖分生组织（SAM）、幼叶、叶原基和小穗原基中表达。进化树显示 TaWRKY74s 与水稻中的 OsWRKY74s 密切相关。此外，在正常条件下，TaWRKY74s-RNAi 转基因植株的分蘖数明显少于野生型植株。此外，在低磷胁迫下，RNAi 转基因植株的分蘖数也明显低于野生型植株，且增加了降低幅度。这表明 TaWRKY74s 与磷反应有关，可影响小麦的分蘖数。
本研究结果表明，TaWRKY74s 是小麦对低磷胁迫反应的关键基因，可能通过脱落酸（ABA）和生长素信号转导途径调节小麦分蘖数。本研究为进一步研究 TaWRKY74s 在低磷环境中的作用机制奠定了基础，对小麦的抗逆性育种具有重要意义。
