Shaker K+ channel NKT3A enhances potassium uptake and transport in tobacco (Nicotiana tabacum L.) seedlings under low potassium stress.

Abstract

One of the nutrients that is necessary for plant growth and development is potassium (K⁺). The uneven production and distribution of global potassium resources significantly challenge crop yields and quality. A moderate increase in the potassium content within plants can enhance both crop yield and quality. This study identifies the Shaker K⁺ channel NKT3A within the model crop, tobacco. The yeast heterologous expression system demonstrated its capability for K⁺ inward transportation. GUS staining and RT-qPCR analyses of the constructed promoter materials revealed NKT3A's activity during the tobacco seedling stage. Expression levels are higher in the leaf and stems, with low potassium levels inducing upregulation of its expression, also observed in roots. Gene editing technology was employed to construct overexpression and knockout mutants, with subsequent measurement of their phenotypes. Results indicate that NKT3A expression enhances facilitates potassium absorption and transport in tobacco seedlings under low potassium conditions. For the first time, this article identifies the Shaker potassium channel gene NKT3A, which functions as an inward rectifier K⁺ channel in tobacco. It elucidates the gene's role in regulating potassium distribution under low potassium conditions, thereby deepening our understanding of plant responses in such environments and offering a potential target for enhancing crop potassium use efficiency.