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A potassium (K)-transporter, OsHAK3, is required for K- homeostasis in rice under low-K and high-salinity conditions
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  • Linan Zhang,
  • Xiangyu Sun,
  • Xuan Chen,
  • Mengyun Huang,
  • Tengfei Xiao,
  • Yun Mo,
  • Yu Pan,
  • Shuai Guo,
  • Yanfang Li,
  • Zhiwei Sun,
  • Zihan Chen,
  • Dandan Mao,
  • Liangbi Chen,
  • Sheng Luan
Linan Zhang
Hunan Normal University
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Xiangyu Sun
Hunan Institute of Microbiology
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Xuan Chen
Hunan Normal University
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Mengyun Huang
Hunan Normal University
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Tengfei Xiao
Hunan Normal University
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Yun Mo
Hunan Institute of Microbiology
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Yu Pan
Hunan Normal University
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Shuai Guo
Hunan Normal University
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Yanfang Li
Hunan Normal University
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Zhiwei Sun
Hunan Normal University
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Zihan Chen
Hunan Normal University
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Dandan Mao
Hunan Normal University
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Liangbi Chen
Hunan Normal University
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Sheng Luan
University of California Berkeley
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Abstract

Potassium (K+) is a macronutrient for plant growth and development. Although a number of K-transporters are encoded in various plant genomes, functional characterization of these transport genes have lagged behind of genomic information in crop plants. In rice genome, a large expansion of high-affinity K-transporters (HAKs/KUPs/KTs) has been identified as compared to those in Arabidopsis genome suggesting a functional diversity of these transporters in cereals. We report here the functional characterization of a HAK member, OsHAK3, in rice using CRISPR-assisted genetic analysis. Expression of OsHAK3 was mainly found in roots and its protein was targeted to the plasma membrane. Loss of function of OsHAK3 led to a reduction of K+ uptake rate and K+ content, consistent with the finding that mutant plants became stunted under low-K+ conditions. In addition, the growth of Oshak3 mutants was more sensitive to salt stress due to altered K/Na ratio in the plants. Together, our data demonstrate that OsHAK3 plays a crucial role in K+ homeostasis, especially under K+-limited conditions and when plants face salinity stress.