Tausta S Lori, Berbasova Tanya, Peverelli Martin, Strobel Scott A
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510.
Plant Physiol. 2021 Mar 21. doi: 10.1093/plphys/kiab131.
Fluoride is everywhere in the environment, yet it is toxic to living things. How biological organisms detoxify fluoride has been unknown until recently. Fluoride-specific ion transporters in both prokaryotes (Fluoride channel; Fluc) and fungi (Fluoride Exporter; FEX) efficiently export fluoride to the extracellular environment. FEX homologs have been identified throughout the plant kingdom. Understanding the function of FEX in a multicellular organism will reveal valuable knowledge about reducing toxic effects caused by fluoride. Here, we demonstrate the conserved role of plant FEX (FLUORIDE EXPORTER) in conferring fluoride tolerance. Plant FEX facilitates the efflux of toxic fluoride ions from yeast cells and is required for fluoride tolerance in plants. A CRISPR/Cas9-generated mutation in Arabidopsis thaliana FEX renders the plant vulnerable to low concentrations (100-µM) of fluoride at every stage of development. Pollen is particularly affected, failing to develop even at extremely low levels of fluoride in the growth medium. The action of the FEX membrane transport protein is the major fluoride defense mechanism in plants.
氟化物在环境中无处不在，但对生物有毒。直到最近，生物有机体如何解毒氟化物仍是未知的。原核生物（氟化物通道；Fluc）和真菌（氟化物转运蛋白；FEX）中的氟化物特异性离子转运蛋白能有效地将氟化物输出到细胞外环境。在整个植物界都已鉴定出FEX同源物。了解FEX在多细胞生物中的功能将揭示有关减少氟化物毒性作用的宝贵知识。在这里，我们证明了植物FEX（氟化物转运蛋白）在赋予植物耐氟性方面的保守作用。植物FEX促进有毒氟离子从酵母细胞外流，并且是植物耐氟性所必需的。拟南芥FEX中由CRISPR/Cas9产生的突变使植物在发育的每个阶段都易受低浓度（100μM）氟化物的影响。花粉受到的影响尤为明显，即使在生长培养基中氟化物含量极低的情况下也无法发育。FEX膜转运蛋白的作用是植物主要的氟化物防御机制。
