Genome-Wide Identification and Expression Analysis of the <i>Shaker</i> K⁺ Channel Gene Family in Cassava (<i>Manihot esculenta</i> Crantz) Under Potassium Stress

Abstract

Shaker K+ channel proteins are responsible for potassium (K+) uptake and transport, playing a critical role in plant growth, development, and adaptation to K+ deficiency. Cassava, a key tropical root crop, is known for its characteristic of resilience to nutrient-poor soil and drought stress. However, the Shaker K+ channel gene family in cassava has not yet been characterized. In this study, 13 Shaker channel genes were identified from the near telomere-to-telomere (T2T) cassava genome using bioinformatics analysis. Phylogenetic relationships classified these genes into five distinct subfamilies, and all encoded proteins contained the conserved GYGD/GYGE motif typical of Shaker channels. Protein interaction network predictions revealed potential interactions among the Shaker family, as well as with the potassium transporter HAK5. Tissue-specific expression pattern analysis showed that MeGORK and MeAKT1.2 were expressed in all tissues. Furthermore, quantitative real-time PCR (qRT-PCR) analysis was conducted to examine the transcriptional levels of Shaker K+ channel gene family members in the roots and leaves of two cassava germplasms with different low-potassium tolerance after one month of low-potassium treatment. The results revealed that MeAKT1.2, MeAKT2.2, and MeKAT1 exhibited distinct expression patterns between the two germplasms, with higher expression levels observed in the potassium-tolerant germplasm. Therefore, these three genes may serve as important candidate genes for potassium stress tolerance in cassava. In summary, this study provides valuable insights into the characteristics and biological functions of the Shaker K+ channel gene family in cassava and identifies potential candidate genes for breeding or engineering potassium-efficient cassava cultivars.

Keywords

• <i>Shaker</i> K⁺ channel gene
• cassava
• potassium stress
• expression patterns
• potassium utilization