CsWRKY17 enhances Al accumulation by promoting pectin deesterification in tea plant

Abstract

The tea plant (Camellia sinensis) is a typical crop that accumulates aluminum (Al). Although the physiological mechanisms by which this occurs are well understood, their molecular mechanisms remain elusive. Here, an integrative approach combining quantitative trait locus (QTL) mapping of controlled hybridized populations and comparative transcriptomic analysis using samples treated with different Al concentrations was applied to identify candidate genes associated with Al accumulation in tea plants. Consequently, 41 candidate genes were selected using genome functional annotation of the qAl09 locus in the region of 35 256 594-57 378 817 bp on chromosome 7. Finally, a key gene, CsWRKY17, was identified as encoding a nucleus-localized transcription factor involved in regulating Al accumulation in tea plants, given the finding of a high correlation between its expression level and Al content in leaves. Overexpression of CsWRKY17 in Arabidopsis increased pectin deesterification, sensitivity to Al stress, and Al accumulation in leaves. Expression of the pectin methylesterase gene CsPME6 was found to be highly consistent with CsWRKY17 expression under various Al concentrations. In addition, experiments using a yeast monoclonal, electrophoresis mobility shift assay and dual-luciferase reporter (DLR) system confirmed that CsWRKY17 activated CsPME6 promoter activity. Antisense oligodeoxynucleotide silencing revealed a positive association between CsPME6 expression and Al accumulation in tea shoots. In conclusion, this study suggests that CsWRKY17 promoted the process of pectin deesterification by binding to the CsPME6 promoter, thereby enhancing Al enrichment in tea plants. Our findings lay the foundation for studying the precise mechanisms through which Al enriched in tea leaves.

Acknowledgements

This work was supported by the National Key Research and Development Program of China (2021YFD1601100), China Agriculture Research System of MOF and MARA (CARS-19), the Chinese Academy of Agricultural Sciences through the Agricultural Science and Technology Innovation Program (CAAS-ASTIP-2021-TRICAAS), the Jiangxi Province Talent Plan (jxsq2023102020), Yunnan Province of Science and Technology Department (202449CE340010), and the Innovation Center Fund for Agricultural Science and Technology in Hubei Province of China (2023-620-005-001).

Author contributions

L.C., Y.M., and J.C. conceived and supervised this study; D.H., X.C., R.T., and H.W. performed the experiments; D.H. and L.J. designed the research and analyzed the data; J.C. and J.M. provided suggestions on the manuscript; D.H. and L.C. wrote and revised the manuscript.

Data availability

The raw RNA-seq data are available in the NCBI Sequence Read Archive under BioProject PRJNA1137106 and PRJNA1229406.

Conflict of interest statement

The authors declare there is no conflict of interest.

Supplementary data

Supplementary data is available at Horticulture Research online.

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