Two AP2/ERF transcription factors coregulate OsHAK1 to modulate potassium and cesium uptake in rice

作者：Mengqi Li, Weihong Li, Yang Zeng, Xiangbin Lu, Xuesong Li, Hongye Qu, Mian Gu, Huimin Feng, Xin‐Yuan Huang, Ling Yu, Guohua Xu · 发表于：The Plant Cell · 年份：2025 · DOI：10.1093/plcell/koaf205 · 被引用次数：5 · 研究领域：Plant Stress Responses and Tolerance、Plant Genetic and Mutation Studies、Plant Micronutrient Interactions and Effects

The Group-I alkali metals potassium (K) and cesium (Cs) serve as an essential nutrient and a harmful element, respectively. In rice (Oryza sativa), the high-affinity K+ (HAK) transporter OsHAK1 contributes to K+ and Cs+ acquisition; however, its regulatory mechanism remains unclear. Here, we report 2 OsHAK1 regulators belonging to the APETALA2/ethylene responsive factor family, designated POTASSIUM TRANSPORTER REGULATOR 1/2 (KTR1/2). Low K+ suppresses KTR1 but induces KTR2 expression. KTR1 inhibits and KTR2 enhances OsHAK1 expression. KTR1-knockout increases and KTR2-knockout decreases K+ and Cs+ uptake. Notably, KTR2 activates KTR1 expression, and the single mutation of KTR2 has a similar effect as the double mutation of KTR1 and KTR2 in impairing rice growth and grain yield. Furthermore, OsHAK1 inactivation in ktr1 mutants or KTR2-overexpression lines reduces Cs+ content to a similar level as in the oshak1 mutant. Enhancing KTR2 expression driven by its native promoter increases grain yield and K+ uptake. Variation in K+ content in grain is associated with differences of K+ content in soils where rice accessions show a distinct combination of KTR1, KTR2, and OsHAK1 haplotypes. These results demonstrate that KTR1 and KTR2 play critical roles in the K+-mediated regulation of OsHAK1 expression, thus controlling K+ and Cs+ uptake and allowing rice to adapt to varying K+ supplies.