Table_1_Identification and Characterization of Shaker K+ Channel Gene Family in Foxtail Millet (Setaria italica) and Their Role in Stress Response.XLSX

Potassium (K+) is one of the indispensable elements in plant growth and development. The Shaker K+ channel protein family is involved in plant K+ uptake and distribution. Foxtail millet (Setaria italica), as an important crop, has strong tolerance and adaptability to abiotic stresses. However, no systematic study focused on the Shaker K+ channel family in foxtail millet. Here, ten Shaker K+ channel genes in foxtail millet were identified and divided into five groups through phylogenetic analysis. Gene structures, chromosome locations, cis-acting regulatory elements in promoter, and post-translation modification sites of Shaker K+ channels were analyzed. In silico analysis of transcript level demonstrated that the expression of Shaker K+ channel genes was tissue or developmental stage specific. The transcription levels of Shaker K+ channel genes in foxtail millet under different abiotic stresses (cold, heat, NaCl, and PEG) and phytohormones (6-BA, BR, MJ, IAA, NAA, GA3, SA, and ABA) treatments at 0, 12, and 24 h were detected by qRT-PCR. The results showed that SiAKT1, SiKAT3, SiGORK, and SiSKOR were worth further research due to their significant responses after most treatments. The yeast complementation assay verified the inward K+ transport activities of detectable Shaker K+ channels. Finally, we found interactions between SiKAT2 and SiSNARE proteins. Compared to research in Arabidopsis, our results showed a difference in SYP121 related Shaker K+ channel regulation mechanism in foxtail millet. Our results indicate that Shaker K+ channels play important roles in foxtail millet and provide theoretical support for further exploring the K+ absorption mechanism of foxtail millet under abiotic stress.

钾离子（K+）是植物生长与发育中不可或缺的元素之一。Shaker K+通道蛋白家族参与植物钾离子的吸收与分配。狐尾草（Setaria italica）作为一种重要的作物，对非生物胁迫具有较强的耐受性和适应性。然而，目前尚无系统性的研究聚焦于狐尾草中的Shaker K+通道家族。本研究中，我们通过系统发育分析，鉴定了狐尾草中的十个Shaker K+通道基因，并将其分为五组。对Shaker K+通道的基因结构、染色体定位、启动子中的顺式作用调控元件以及翻译后修饰位点进行了分析。转录水平上的计算机模拟分析表明，Shaker K+通道基因的表达具有组织或发育阶段特异性。通过qRT-PCR检测了狐尾草在冷、热、NaCl和PEG等不同非生物胁迫以及6-BA、BR、MJ、IAA、NAA、GA3、SA和ABA等植物激素处理下，0、12和24小时Shaker K+通道基因的转录水平。结果表明，SiAKT1、SiKAT3、SiGORK和SiSKOR在多数处理后的显著响应使其值得进一步研究。酵母互补实验验证了可检测到的Shaker K+通道的内向钾离子转运活性。最终，我们发现SiKAT2与SiSNARE蛋白之间存在相互作用。与拟南芥的研究相比，我们的结果表明狐尾草中与SYP121相关的Shaker K+通道调控机制存在差异。我们的研究结果指出，Shaker K+通道在狐尾草中发挥着重要作用，并为在非生物胁迫下进一步探究狐尾草的钾离子吸收机制提供了理论依据。