Auxin is unique among plant hormones in that its function requires polarized transport across plant cells. A chemiosmotic model was proposed to explain how polar auxin transport is derived by the H+ gradient across the plasma membrane (PM) established by PM H+-adenosine triphosphatases (ATPases). However, a classical genetic approach by mutations in PM H+-ATPase members did not result in the ablation of polar auxin distribution, possibly due to functional redundancy in this gene family. To confirm the crucial role of PM H+-ATPases in the polar auxin transport model, we employed a chemical genetic approach. Through a chemical screen, we identified protonstatin-1 (PS-1), a selective small-molecule inhibitor of PM H+-ATPase activity that inhibits auxin transport. Assays with transgenic plants and yeast strains showed that the activity of PM H+-ATPases affects auxin uptake as well as acropetal and basipetal polar auxin transport. We propose that PS-1 can be used as a tool to interrogate the function of PM H+-ATPases. Our results support the chem-iosmotic model in which PM H+-ATPase itself plays a fundamental role in polar auxin transport.

Yongqing Yang;Xiaohui Liu;Wei Guo;Wei Liu;Wei Shao;Jun Zhao;Junhong Li;Qing Dong;Liang Ma;Qun He;Yingzhang Li;Jianyong Han;Xiaoguang Lei

State Key Laboratory of Plant Physiology and Biochemistry,College of Biological Sciences,China Agricultural University,Beijing 100193,China;Beijing National Laboratory for Molecular Sciences,Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education,Department of Chemical Biology,College of Chemistry and Molecular Engineering,Synthetic and Functional Biomolecules Center,and Peking-Tsinghua Center for Life Sciences,Peking University,Beijing 100871,China;Institute of Food Science and Technology,Chinese Academy of Agricultural Sciences,Beijing 100193,China;Department of Dermatology,Peking University First Hospital,Beijing 100034,China;Iomics Biosciences Inc.,Beijing 100102,China;College of Biological Sciences,China Agricultural University,Beijing 100193,China

植物学报（英文版）

[1]Yongqing Yang;Xiaohui Liu;Wei Guo;Wei Liu;Wei Shao;Jun Zhao;Junhong Li;Qing Dong;Liang Ma;Qun He;Yingzhang Li;Jianyong Han;Xiaoguang Lei-.Testing the polar auxin transport model with a selective plasma membrane H+-ATPase inhibitor)[J].植物学报（英文版）,2022(06):1229-1245

chemiosmotic,triphosphatases,ATPases,protonstatin,Assays,acropetal,basipetal,iosmotic

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