J Integr Plant Biol ›› 2025, Vol. 67 ›› Issue (11): 2897-2911.DOI: 10.1111/jipb.70029

• • 上一篇    下一篇

  

  • 收稿日期:2025-01-12 接受日期:2025-08-10 出版日期:2025-11-01 发布日期:2025-11-08

The rice cation/calcium exchanger OsCCX2 is involved in calcium signal clearance and osmotic tolerance

Xiaohua Hao1,2†, Xinjie Zhao2†, Zijing Xie2,3, Xinzhou Jin2, Shaozhuang Li2, Sha Wu2, Liqun Huang2, Lianfu Tian2* and Dongping Li2*   

  1. 1. Agricultural Products Processing and Food Safety Key Laboratory of Hunan Higher Education, College of Life and Environmental Science, Hunan University of Arts and Science, Changde 415000, China
    2. Hunan Province Key Laboratory of Crop Sterile Germplasm Resource Innovation and Application, College of Life Science, Hunan Normal University, Changsha 410081, China
    3. Hunan Provincial Key Laboratory of the Traditional Chinese Medicine Agricultural Biogenomics, Changsha Medical University, Changsha 410219, China

    †These authors contributed equally to this work.
    *Correspondences: Lianfu Tian (hnsdtlf@163.com); Dongping Li (dli@hunnu.edu.cn, Dr. Li is fully responsible for the distribution of all materials associated with this article).
  • Received:2025-01-12 Accepted:2025-08-10 Online:2025-11-01 Published:2025-11-08
  • Supported by:
    This work was supported by grants of National Nature Science Foundation of China (32071930), the Key Project of Developmental Biology and Breeding from Hunan Province (2000XKQ0203), China Postdoctoral Science Foundation (2023M741146), Project of Hunan Provincial National Nature Science Foundation (2023JJ40429, 2024JJ6312), Project of Hunan Provincial Department of Education (23B0087), and Project of Changsha Municipal Natural Science Foundation (kq2208164, kq2402157).

Abstract: Hyperosmolality-triggered physiological drought hinders plant growth and development, leading to a drop in crop yields. Hyperosmolality triggers calcium signaling, and yet how osmotic-induced calcium signaling participates in cellular osmotic response remains enigmatic. To date, several Ca2+ channels and transporters have been identified to regulate osmotic-induced calcium signal generation (CaSG) or Ca2+ homeostasis. However, there has been no report on their function in calcium signal clearance (CaSC) in plants, especially in crops. Here, we investigated the role of a rice cation/calcium exchanger OsCCX2 in modulating calcium signaling dynamics using two distinct calcium reporters aequorin and GCaMP6s. The results showed that, under osmotic stress conditions, CaSC was significantly delayed in both root and guard cells of ccx2 mutants compared with the wild-type. Further studies revealed that hyperosmotic stress-triggered influxes of sodium (Na+), potassium (K+), and chloride (Cl−) ions were significantly reduced in ccx2 mutants, resulting in a significantly smaller range of osmotic pressure and water potentials (Ψw) adjustment. In addition, the stomatal response was impaired, with a faster water loss in ccx2 in response to hyperosmotic stress. Furthermore, the absence of OsCCX2 altered the expression patterns of key osmotic-responsive genes, but their transcriptional activation was unaffected. Collectively, these changes ultimately led to reduced hyperosmotic stress tolerance in the mutants. Additionally, OsCCX2 is likely to be located in the endoplasmic reticulum and plasma membrane, and possess Na+/Ca2+ exchange activity. To sum up, our findings provide evidence that OsCCX2, as a CaSC regulator, is involved in cell osmotic adjustment, water homeostasis and osmotic stress tolerance in rice, which offers new insight into potential applications in drought-resistant crop improvement.

Key words: calcium signal clearance (CaSC), Oryza sativa L, OsCCX2, osmotic adjustment

[an error occurred while processing this directive]