Identification and Characterization of Shaker K+ Channel Gene Family in Foxtail Millet (Setaria italica) and Their Role in Stress Response
Ben Zhang, Yue Leon Guo, Hui Wang, Xiaoxia Wang, Mengtao Lv, Pu Yang, Lizhen Zhang
Abstract
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.