WNK kinases are a unique class of serine/threonine protein kinases that lack a conserved catalytic lysine residue in the kinase domain, hence the name WNK (with no K, i.e., lysine). WNK kinases are involved in various physiological processes in plants, such as circadian rhythm, flowering time, and stress responses. In this study, we identified 26 WNK genes in soybean and analyzed their phylogenetic relationships, gene structures, chromosomal distribution, cis-regulatory elements, expression patterns, and conserved protein motifs. The soybean WNK genes were unevenly distributed on 15 chromosomes and underwent 21 segmental duplication events during evolution. We detected 14 types of cis-regulatory elements in the promoters of the WNK genes, indicating their potential involvement in different signaling pathways. The transcriptome database revealed tissue-specific and salt stress-responsive expression of WNK genes in soybean, the second of which was confirmed by salt treatments and qRT-PCR analysis. We found that most WNK genes were significantly up-regulated by salt stress within 3 h in both roots and leaves, except for WNK5, which showed a distinct expression pattern. Our findings provide valuable insights into the molecular characteristics and evolutionary history of the soybean WNK gene family and lay a foundation for further analysis of WNK gene functions in soybean.

WNK 激酶是一类独特的丝氨酸/苏氨酸蛋白激酶，其激酶结构域中缺乏保守的催化赖氨酸残基，因此命名为 WNK（不含 K，即赖氨酸）。 WNK 激酶参与植物的多种生理过程，例如昼夜节律、开花时间和应激反应。在本研究中，我们鉴定了大豆中的 26 个WNK基因，并分析了它们的系统发育关系、基因结构、染色体分布、顺式调控元件、表达模式和保守蛋白基序。大豆WNK基因在15条染色体上分布不均匀，在进化过程中经历了21次节段重复事​​件。我们在WNK基因的启动子中检测到 14 种顺式调节元件，表明它们可能参与不同的信号通路。转录组数据库揭示了大豆中WNK基因的组织特异性和盐胁迫响应性表达，其中第二个通过盐处理和 qRT-PCR 分析得到了证实。我们发现大多数WNK基因在盐胁迫下 3 小时内在根和叶中均显着上调，但WNK5除外，其表现出独特的表达模式。我们的研究结果为了解大豆WNK基因家族的分子特征和进化历史提供了有价值的见解，并为进一步分析大豆WNK基因功能奠定了基础。