Agarwal Samridhi, Regon Preetom, Rehman Mehzabin, Tanti Bhaben, Panda Sanjib Kumar
Department of Biochemistry, Central University of Rajasthan, Bandar Sindri, Ajmer, Rajasthan 305817 India.
Department of Life Science and Bioinformatics, Assam University, Silchar, Assam 788011 India.
3 Biotech. 2021 Mar;11(3):124. doi: 10.1007/s13205-021-02677-z. Epub 2021 Feb 12.
Fluoride exporter genes (FEX) are known for the expulsion of cytoplasmic fluoride, thus preventing fluoride toxicity in plants. In this study, 31 FEX genes were identified across 19 plant species. Camphor Resistance (CrcB) domain was found to be present in all the identified FEX genes in plants. FEX genes were sequentially very conserved among the plants and are located mostly in chloroplast and mitochondria. The tertiary structure (3D) of FEX1 suggests that FEX genes of plants possess pore I and pore II, necessary for fluoride export. The TTFSGWNQ and GCLSTVSTF motifs were found to be well conserved in pore I and pore II. Phenylalanine (Phe/F) was also present in both the motifs, necessary for fluoride ions recognition and export. Cis-acting analysis in promoter sequences of plant FEX revealed several elements associated with various functions such as phytohormone signaling, integrating biotic and abiotic stress responses in plants. Prolong fluoride exposure causes necrosis in young leaves in Expression of FEX1 and FEX2 were highly induced under exogenous fluoride, thus suggesting a possible role in fluoride detoxification.
The online version contains supplementary material available at 10.1007/s13205-021-02677-z.
氟离子输出基因（FEX）以排出细胞质中的氟离子而闻名，从而防止植物中的氟中毒。在本研究中，在19种植物中鉴定出31个FEX基因。发现植物中所有已鉴定的FEX基因都存在抗樟脑（CrcB）结构域。FEX基因在植物中顺序上非常保守，并且大多位于叶绿体和线粒体中。FEX1的三级结构（3D）表明植物的FEX基因具有氟离子输出所需的孔I和孔II。发现TTFSGWNQ和GCLSTVSTF基序在孔I和孔II中高度保守。苯丙氨酸（Phe/F）也存在于这两个基序中，这是氟离子识别和输出所必需的。对植物FEX启动子序列的顺式作用分析揭示了与各种功能相关的几个元件，如植物激素信号传导、整合植物中的生物和非生物胁迫反应。长时间暴露于氟会导致幼叶坏死。FEX1和FEX2的表达在外源氟处理下高度诱导，因此表明其在氟解毒中可能发挥作用。
在线版本包含可在10.1007/s13205-021-02677-z获取的补充材料。
