OsNRAMP2 facilitates Cd efflux from vacuoles and contributes to the difference in grain Cd accumulation between japonica and indica rice
Wu Yang,
Luo Chen,
Yamei Ma,
Rui Hu,
Jian Wang,
Wenhui Li,
Jingfang Dong,
Tifeng Yang,
Lian Zhou,
Jiansong Chen,
Dilin Liu,
Ning Yu,
Zhixia Liu,
Lingyan Zhou,
Shaohong Zhang,
Junliang Zhao,
Bin Liu
Affiliations
Wu Yang
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Luo Chen
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China; College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, Guangdong, China
Yamei Ma
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Rui Hu
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Jian Wang
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Wenhui Li
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Jingfang Dong
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Tifeng Yang
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Lian Zhou
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Jiansong Chen
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Dilin Liu
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Ning Yu
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Zhixia Liu
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China
Lingyan Zhou
College of Agriculture and Biology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, Guangdong, China
Shaohong Zhang
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China; Corresponding authors.
Junliang Zhao
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China; Corresponding authors.
Bin Liu
Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Key Laboratory of New Technology in Rice Breeding/Guangdong Rice Engineering Laboratory, Guangzhou 510640, Guangdong, China; Corresponding authors.
Cadmium (Cd) accumulation in rice grain is of health concern. Identifying genes involved in grain Cd accumulation and performing molecular breeding may reduce it. In this study, knockout of OsNRAMP2, a member of the NRAMP family, reduced grain Cd concentrations by more than 38%, and overexpressing OsNRAMP2 increased grain Cd concentrations by more than 50%. Physiological experiments showed that OsNRAMP2 facilitated Cd translocation from root to shoot by positively regulating Cd efflux from the vacuoles. At filling stage, OsNRAMP2 was highly expressed in all tissues except for husk, suggesting its role in Cd remobilization. Changes in OsNRAMP2 expression affected the concentrations of Fe, Mn, Zn, and Cu in grain and also affected rice growth. Phylogenetic analysis showed that the distribution of OsNRAMP2 haplotypes between japonica and indica was different. Among the four haplotypes of OsNRAMP2, Hap 1, with a 6-bp nucleotide insertion in exon 1, had grain Cd concentration at least 45.3% lower than any of the other three haplotypes. Almost all (99.3%) japonica accessions but rare indica accessions (4.44%) from the 3K sequenced rice genomes carry Hap 1 of OsNRAMP2. Our study sheds light on the molecular mechanism of grain Cd accumulation and provides a promising target for low-Cd rice breeding.
