EgKT2-1, an inwardly rectifying Shaker-type potassium channel in oil palm that correlates with oil yield

The oil extracted from the mesocarp of oil palm ( Elaeis guineensis , Jacq.) drupes is the world’s leading source of vegetable oil. Oil palm cultivation requires large amounts of mineral nutrients supplied through fertilization, representing a major production cost. Among essential nutrients, potassium (K⁺) plays a critical role in plant growth and fruit development. However, the mechanisms underlying K⁺ transport and its relationship with yield remain poorly understood. Here, we identified and characterized EgKT2-1 , a Shaker-like potassium channel belonging to the AKT2-like subfamily. Quantitative PCR analyses showed that EgKT2-1 is expressed in leaves, meristem, and during early fruit development, with higher transcript abundance during early fruit development coinciding with increased K⁺ accumulation. In situ hybridization localized EgKT2-1 transcripts to the root cortex and phloem tissues, leaf palisade parenchyma, and mesocarp cells during early fruit development. These expression patterns are consistent with a potential contribution of EgKT2-1 to K⁺ transport and allocation between source and sink tissues. Although sequence similarity places EgKT2-1 within the weakly rectifying AKT2-like subfamily, electrophysiological characterization in Xenopus laevis oocytes revealed inwardly rectifying channel activity, suggesting a potential role in K⁺ uptake. EgKT2-1 expression was higher in an oil palm progeny C3 which exhibited greater K⁺ allocation to aerial organs and greater oil yield. Together, these findings identify EgKT2-1 as an inwardly rectifying K⁺ channel potentially involved in K⁺ transport and redistribution during oil palm development and suggest a correlation between EgKT2-1 expression, K⁺ allocation, and oil yield variation.