RT Journal Article SR Electronic T1 The Cation/H+ exchanger OsCAX2 is involved in cadmium tolerance and accumulation through vacuolar sequestration in rice JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.11.22.517486 DO 10.1101/2022.11.22.517486 A1 Zou, Wenli A1 Zhan, Junhui A1 Meng, Lijun A1 Chen, Yuetong A1 Chen, Dandan A1 Zhang, Mingpei A1 He, Haohua A1 Chen, Jingguang A1 Ye, Guoyou YR 2022 UL http://biorxiv.org/content/early/2022/11/24/2022.11.22.517486.abstract AB Excessive cadmium (Cd) in rice grains is a serious food safety problem. The development of Cd-safe varieties requires the identification of germplasms and genes with major effect on Cd accumulation but without negative effects on other important traits. Here, we reported that OsCAX2, a member of the rice Cation/H+ exchanger (CAX) family, is an important Cd transporter. OsCAX2 encodes a tonoplast-localized protein and is strongly upregulated by Cd, mainly expresses in root exodermis, parenchyma in cortex, endodermis and stele cells. Depletion of OsCAX2 resulted in enhanced Cd sensitivity and root-to-shoot translocation in rice, while overexpression of OsCAX2 significantly increased Cd tolerance and reduced Cd transport by promoting root Cd influx and vacuolar storage, which ultimately reduced Cd transport via xylem. OsCAX2 also had significant effects on tissues/organs distribution of Cd but had no effects on grain yield and agronomic traits. Importantly, the OsCAX2 overexpressing lines had more than 70% lower grain Cd accumulation, increased iron (Fe), zinc (Zn) and manganese (Mn) and reduced copper (Cu) accumulation. Therefore, OsCAX2 is an ideal gene for developing Cd-safe rice varieties via transgenic approach.Competing Interest StatementThe authors have declared no competing interest.