Testing the polar auxin transport model with a selective plasma membrane H+ -ATPase inhibitor.

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 chemiosmotic model in which PM H+ -ATPase itself plays a fundamental role in polar auxin transport. © 2022 Institute of Botany, Chinese Academy of Sciences.

Citation

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. Journal of integrative plant biology. 2022 Jun;64(6):1229-1245

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PMID: 35352470

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