Al-induced CsUGT84J2 enhances flavonol and auxin accumulation to promote root growth in tea plants

Abstract

Although Al is not necessary or even toxic to most plants, it is beneficial for the growth of tea plants. However, the mechanism through which Al promotes root growth in tea plants remains unclear. In the present study, we found that flavonol glycoside levels in tea roots increased following Al treatment, and the Al-induced UDP glycosyltransferase CsUGT84J2 was involved in this mechanism. Enzyme activity assays revealed that rCsUGT84J2 exhibited catalytic activity on multiple types of substrates, including phenolic acids, flavonols, and auxins in vitro. Furthermore, metabolic analysis with UPLC-QqQ-MS/MS revealed significantly increased flavonol and auxin glycoside accumulation in CsUGT84J2-overexpressing Arabidopsis thaliana. In addition, the expression of genes involved in the flavonol pathway as well as in the auxin metabolism, transport, and signaling pathways was remarkably enhanced. Additionally, lateral root growth and exogenous Al stress tolerance were significantly improved in transgenic A. thaliana. Moreover, gene expression and metabolic accumulation related to phenolic acids, flavonols, and auxin were upregulated in CsUGT84J2-overexpressing tea plants but downregulated in CsUGT84J2-silenced tea plants. In conclusion, Al treatment induced CsUGT84J2 expression, mediated flavonol and auxin glycosylation, and regulated endogenous auxin homeostasis in tea roots, thereby promoting the growth of tea plants. Our findings lay the foundation for studying the precise mechanisms through which Al promotes the growth of tea plants.

Acknowledgements

This work was supported by the Natural Science Foundation of China (31902069 and U21A2023), the Youth Science and Technology Talents Support Program (2020) by Anhui Association for Science and Technology (RCTJ202010), the College Students’ Innovative Training Program of Anhui Province (S202110364265) and the Collegiate Collaborative Innovation Foundation of Anhui Province (GXXT-2020-081).

Author contributions

The presented study was conducted in collaboration by all authors. X.J, S.L., L.G., and T.X. conceived and designed the experiments. S.L., X.J., D.K., Y.S., X.H., and Z.F. performed the experiments. S.L., X.J., and Z.F. analysed the data. X.J., S.L., L.G., Y.L., and T.X. wrote the manuscript. All authors reviewed the manuscript.

Data availability

All relevant data in this study are provided in the article and its supplementary file. The genotypic datasets presented in this study can found at: https://www.ncbi.nlm.nih.gov/, with accession numbers CsUGT84J2 (KP682363.1).

Conflict of interest statement

The authors declare no competing financial interests.

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