© 2016 by the authors; licensee MDPI, Basel, Switzerland. Tea plant is known to be a hyper-accumulator of fluoride (F). Over-intake of F has been shown to have adverse effects on human health, e.g., dental fluorosis. Thus, understanding the mechanisms fluoride accumulation and developing potential approaches to decrease F uptake in tea plants might be beneficial for human health. In the present study, we found that pretreatment with the anion channel inhibitor NPPB reduced F accumulation in tea plants. Simultaneously, we observed that NPPB triggered Ca 2+ efflux from mature zone of tea root and significantly increased relative CaM in tea roots. Besides, pretreatment with the Ca 2+ chelator (EGTA) and CaM antagonists (CPZ and TFP) suppressed NPPB-elevated cytosolic Ca 2+ fluorescence intensity and CaM concentration in tea roots, respectively. Interestingly, NPPB-inhibited F accumulation was found to be significantly alleviated in tea plants pretreated with either Ca 2+ chelator (EGTA) or CaM antagonists (CPZ and TFP). In addition, NPPB significantly depolarized membrane potential transiently and we argue that the net Ca 2+ and H + efflux across the plasma membrane contributed to the restoration of membrane potential. Overall, our results suggest that regulation of Ca 2+ -CaM and plasma membrane potential depolarization are involved in NPPB-inhibited F accumulation in tea plants.
Zhang, X. C., Gao, H. J., Yang, T. Y., Wu, H. H., Wang, Y. M., Zhang, Z. Z., & Wan, X. C. (2016). Anion channel inhibitor NPPB-inhibited fluoride accumulation in tea plant (Camellia sinensis) is related to the regulation of Ca2+, CaM and depolarization of plasma membrane potential. International Journal of Molecular Sciences, 17(1), 2–14. https://doi.org/10.3390/ijms17010057