Genome-wide identification of Shaker K + channel family in Nicotiana tabacum and functional analysis of NtSKOR1B in response to salt stress.

Soil salinization poses a mounting global ecological and environmental threat. The identification of genes responsible for negative regulation of salt tolerance and their utilization in crop improvement through gene editing technologies emerges as a swift strategy for the effective utilization of saline-alkali lands. One efficient mechanism of plant salt tolerance is maintaining the proper intracellular K ⁺ /Na ⁺ ratio. The Shaker K ⁺ channels play a crucial role in potassium absorption, transport, and intracellular potassium homeostasis in plant cells. Here, the study presents the first genome-wide identification of Shaker K ⁺ channels in Nicotiana tabacum L., along with a detailed bioinformatic analysis of the 20 identified members. Transcriptome analysis revealed a significant up-regulation of NtSKOR1B , an outwardly-rectifying member predominantly expressed in the root tissue of tobacco seedlings, in response to salt stress. This finding was then confirmed by GUS staining of ProNtSKOR1B::GUS transgenic lines and RT-qPCR analysis. Subsequently, NtSKOR1B knockout mutants ( ntskor1 ) were then generated and subjected to salt conditions. It was found that ntskor1 mutants exhibit enhanced salt tolerance, characterized by increased biomass, higher K ⁺ content and elevated K ⁺ /Na ⁺ ratios in both leaf and root tissues, compared to wild-type plants. These results indicate that NtSKOR1B knockout inhibits K ⁺ efflux in root and leaf tissues of tobacco seedlings under salt stress, thereby maintaining higher K ⁺ /Na ⁺ ratios within the cells. Thus, our study identifies NtSKOR1B as a negative regulator of salt tolerance in tobacco seedlings.
Competing Interests: Author YW is employed by China Tobacco Shandong Industrial. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2024 Yuan, Nong, Hunpatin, Shi, Su, Xu, Wang, Zhang, Ning, Liu and Wang.)