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 f...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.展开更多
基金supported by the National Natural Science Foundation of China(31901488)the Guangdong Basic and Applied Basic Research Foundation(2020A1515010193)+3 种基金the Innovation Team Project of Guangdong Modern Agricultural Industrial System(2021KJ106,2022KJ106)the Scientific and Technological Plan of Guangzhou(201804020078,202102021005)the Special fund for scientific innovation strategy-construction of high level Academy of Agriculture Science(R2021PY-QF002,202027,R2019-JX001,R2021PY-QF001)the Guangdong Key Laboratory of New Technology in Rice Breeding(2020B1212060047).
文摘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.
