International Journal of Molecular Sciences (Jul 2022)

<i>Camellia sinensis</i> Chloroplast Fluoride Efflux Gene <i>CsABCB9</i> Is Involved in the Fluoride Tolerance Mechanism

  • Bingbing Luo,
  • Min Guang,
  • Wenjing Yun,
  • Shitao Ding,
  • Suna Ren,
  • Hongjian Gao

DOI
https://doi.org/10.3390/ijms23147756
Journal volume & issue
Vol. 23, no. 14
p. 7756

Abstract

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Soil is a main source of fluoride for plants. The tea plants (Camellia sinensis) accumulate excessive amounts of fluoride in their leaves compared to other plants, but their fluoride tolerance mechanism is poorly understood. A chloroplast fluoride efflux gene (CsABCB9) was newly discovered by using transcriptome analysis, cloned from Camellia sinensis, and its function was demonstrated in the fluoride detoxication mechanism in Escherichia coli/Xenopus laevis oocytes and Arabidopsis thaliana. CsABCB9 is expressed in tea leaves upon F− treatment. The growth of tea, E. coli, and Arabidopsis were inhibited by F− treatment. However, growth of CsABCB9-overexpression in E. coli was shown to increase with lower fluoride content under F− treatment compared to the control. Furthermore, chlorophyll, xanthophyll and soluble sugar contents of CsABCB9-overexpression in Arabidopsis were improved under F− treatment compared to the wild type. CsABCB9 functions in fluoride transport, and the mechanism by which CsABCB9 improves fluoride resistance in tea is mainly chloroplast protection through fluoride efflux.

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