CIRCADIAN CLOCK-ASSOCIATED 1 represses thermotolerance by inhibiting HEAT SHOCK FACTOR A2 expression in nonheading Chinese cabbage

Abstract

In the context of global warming, elevated temperatures present serious challenges to the growth, quality, and productivity of nonheading Chinese cabbage (NHCC). Understanding the mechanisms underlying thermotolerance in NHCCs is therefore critically important. In this study, we investigated the influence of heat stress (HS) duration and circadian rhythm on gene expression using time-resolved transcriptome sequencing. The results showed that during the early stages of HS, NHCC primarily engaged in physiological processes such as stimulus perception and signal transduction. In contrast, prolonged HS exposure activated antioxidant metabolism, reduced photosynthetic capacity, and accelerated leaf senescence. Weighted gene coexpression network analysis (WGCNA) further revealed a strong link between circadian regulation and HS responses. Notably, our findings demonstrate that the core circadian clock component CIRCADIAN CLOCK ASSOCIATED 1 (BcCCA1) negatively regulated heat tolerance by repressing the transcription of BcHSFA2. Collectively, these results provide new insights into the molecular mechanisms underlying HS responses in NHCCs and highlight the regulatory role of circadian rhythms in plant thermotolerance.

Acknowledgements

This work was supported by the Shanghai Agricultural Science and Technology Innovation Program (Grant No. K2023015) and Project supported by the Education Department of Hainan Province, project number: Hnjg2025ZD-98.

Author contributions

H.Z. and X.H. provided financial support. D.X. and Y.H. designed and conceived the study. Y.H. performed the experiments and data analysis. D.X. and Y.H. wrote the paper. D.X. and H.Z. revised the manuscript. Y.L. coordinated the study. All the authors read and approved the final manuscript.

Data availability

The data that support the findings of this study will be available in NCBI at (https://dataview.ncbi.nlm.nih.gov/object/PRJNA1282857?reviewer=toselqsndcsesnqickjshkfh36).

Conflicts of interest statement

The authors declare no conflicts of interest.

Supplementary material

Supplementary material is available at Horticulture Research online.

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