J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (3): 703-720.DOI: 10.1111/jipb.13432

• Abiotic Stress Responses • Previous Articles     Next Articles

Coronatine promotes maize water uptake by directly binding to the aquaporin ZmPIP2;5 and enhancing its activity

Rui He1, Huiqing Su2, Xing Wang1, Zhijie Ren3, Kun Zhang1, Tianyu Feng1, Mingcai Zhang1, Zhaohu Li1, Legong Li3, Junhong Zhuang4, Zhizhong Gong5, Yuyi Zhou1* and Liusheng Duan1   

  1. 1. State Key Laboratory of Plant Physiology and Biochemistry, Engineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China;
    2. College of Plant Protection, China Agricultural University, Beijing 100193, China;
    3. Key Laboratory of Plant Gene Resources and Biotechnology for Carbon Reduction and Environmental Improvement, Beijing Municipal Government, College of Life Sciences, Capital Normal University, Beijing 100048, China;
    4. Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China;
    5. State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
    *Correspondence: Yuyi Zhou (zhouyuyi@cau.edu.cn)
  • Received:2022-07-24 Accepted:2022-12-11 Online:2022-12-13 Published:2023-03-01

Abstract: Water uptake is crucial for crop growth and development and drought stress tolerance. The water channel aquaporins (AQP) play important roles in plant water uptake. Here, we discovered that a jasmonic acid analog, coronatine (COR), enhanced maize (Zea mays) root water uptake capacity under artificial water deficiency conditions. COR treatment induced the expression of the AQP gene Plasma membrane intrinsic protein 2;5 (ZmPIP2;5). In vivo and in vitro experiments indicated that COR also directly acts on ZmPIP2;5 to improve water uptake in maize and Xenopus oocytes. The leaf water potential and hydraulic conductivity of roots growing under hyperosmotic conditions were higher in ZmPIP2;5-overexpression lines and lower in the zmpip2;5 knockout mutant, compared to wild-type plants. Based on a comparison between ZmPIP2;5 and other PIP2s, we predicted that COR may bind to the functional site in loop E of ZmPIP2;5. We confirmed this prediction by surface plasmon resonance technology and a microscale thermophoresis assay, and showed that deleting the binding motif greatly reduced COR binding. We identified the N241 residue as the COR-specific binding site, which may activate the channel of the AQP tetramer and increase water transport activity, which may facilitate water uptake under hyperosmotic stress.

Key words: coronatine, osmotic stress, water uptake capacity, ZmPIP2;5

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