Aluminum-activated malate transporter family member CsALMT6 mediates fluoride resistance in tea plants (Camellia sinensis)

Abstract

Tea plant is a fluoride (F)-hyperaccumulator, which poses a potential threat to human health via tea consumption. Reducing F accumulation in fresh tea leaves is crucial for enhancing the safety of tea production at its source. This study aims to isolate novel genes responsible for F accumulation or transport in tea plants. We identified an aluminum (Al)-activated malate transporter gene, CsALMT6, which was hypothesized to be a candidate for differential F accumulation in Camellia sinensis, by employing a combination of transcriptome-wide association study and genome-wide identification of the CsALMT gene family. CsALMT6 exhibited high expression levels in old leaves, and its expression was significantly upregulated in tea plants subjected to F-stress conditions. Furthermore, heterologous expression of CsALMT6 in yeast, Arabidopsis, and Populus conferred F tolerance. However, the expression of F-tolerant hub genes, CsFEX1 and CsFEX2, remained unaffected in CsALMT6-silenced tea plants. Additionally, under F toxicity conditions, the transcription of CsALMT6 was negatively associated with F accumulation in tea plants. In conclusion, CsALMT6 plays a vital role in reducing F accumulation in C. sinensis, thus conferring F tolerance to plant cells.

Acknowledgements

This research was supported by the National Natural Science Foundation of China (32272765 and 31972463), the Natural Science Foundation of Hubei Province (2023AFB877) and the Knowledge Innovation Program of Wuhan-Shuguang Project (2023020201020348). We also thank the public platform of National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops for providing research facilities.

Author Contributions

M.W. and Y.C. conceived and designed the study. Q.L., R.Z. and X.H. performed the experiments and analyzed the data. Q.L. wrote the manuscript. Q.L., D.N., Y.C. and M.W. revised the manuscript.

Data availability

All relevant data in this study are provided in the article and its supplementary file.

Conflict of interest statement

All authors declare that they have no conflict of interest.

Supplementary data

Supplementary data is available at Horticulture Research online.

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