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 (TWAS) 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.

中文翻译：

---

铝活化苹果酸转运蛋白家族成员 CsALMT6 介导茶树 （Camellia sinensis） 的氟化物耐药性


茶树是一种氟化物 （F） 超蓄积器，通过食用茶叶对人类健康构成潜在威胁。减少新鲜茶叶中的 F 积累对于从源头上提高茶叶生产的安全性至关重要。本研究旨在分离茶树中负责 F 积累或运输的新基因。我们通过采用全转录组关联研究 （TWAS） 和 CsALMT 基因家族的全基因组鉴定相结合，鉴定了一个铝 （Al） 激活的苹果酸转运蛋白基因 CsALMT6，该基因被假设为山茶花中差异 F 积累的候选基因。CsALMT6 在老叶中表现出高表达水平，其在 F 胁迫条件下的茶树中表达显著上调。此外，CsALMT6 在酵母、拟南芥和杨树中的异源表达赋予了 F 耐受性。然而，在 CsALMT6 沉默的茶树中，F 耐受枢纽基因 CsFEX1 和 CsFEX2 的表达不受影响。此外，在 F 毒性条件下，CsALMT6 的转录与茶树中 F 的积累呈负相关。总之，CsALMT6 在减少 C. sinensis 的 F 积累中起着至关重要的作用，从而赋予植物细胞对 F 的耐受性。