摘要
In plants,microRNA (miRNA) functions in the post-transcriptional repression of target mRNAs have been well explored.However,the mechanisms regulating the accumulation of miRNAs remain poorly under.stood.Here,we report that distinct mechanisms regulate accumulation of a monocot-specific miRNA,rice (Oryza sativa) miR528.At the transcriptional level,miR528 accumulated to higher levels in older plants than in young seedlings and exhibited aging-modulated gradual accumulation and diurnal rhythms in leaves;at the post-transcriptional level,aging also modulated miR528 levels by enhancing pri-miR528 alter.native splicing.We found that miR528 promotes rice flowering under long-day conditions by targeting RED AND FAR-RED INSENSITIVE2 (OsRFI2).Moreover,natural variations in the MIR528 promoter region caused differences in miR528 expression among rice varieties,which are correlated with their different binding affinities with the transcription factor OsSPL9 that activates the expression of miR528.Taken together,our findings reveal rice plants have evolved sophisticated modes fine-tuning miR528 levels and provide insight into the mechanisms that regulate MIRNA expression in plants.
基金
supported by the National Natural Science Foundation of China (grants 91540203 and 31788103 to X.C.,31771872 to X.S.)
The National Key Research and Development Program of China (2016YFD0100904)
the Genetically Modified Breeding Major Projects (grant no.2016ZX08009001 -005 to X.S.)
the Key Research Program of Frontier Sciences Chinese Academy of Sciences (QYZDY-SSWSMC022 to X.C.)
Strategic Priority Research Program of Chinese Academy of Sciences (XDB27030201 to X.C.)
the State Key Laboratory of Plant Genomics.
