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N6-methyladenosine (m6A),a ubiquitous internal modification of eukaryotic mRNAs,plays a vital role in almost every aspect of mRNA metabolism.However,there is little evidence documenting the role of m6A in regulating alternative polyadenylation (APA) in plants.APA is controlled by a large protein-RNA complex with many components,including CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR30 (CPSF30).In Arabidopsis,CPSF30 has two isoforms and the longer isoform (CPSF30-L) contains a YT512-B Homology (YTH) domain,which is unique to plants.In this study,we showed that CPSF30-L YTH domain binds to m6A in vitro.In the cpsf30-2 mutant,the transcripts of many genes including several important nitrate signaling-related genes had shifts in polyadenylation sites that were correlated with m6A peaks,indicating that these gene transcripts carrying m6A tend to be regulated by APA.Wild-type CPSF30-L could rescue the defects in APA and nitrate metabolism in cpsf30-2,but m6A-binding-defective mutants of CPSF30-L could not.Taken together,our results demonstrated that m6A modification regulates APA in Arabidopsis and revealed that the m6A reader CPSF30-L affects nitrate signaling by controlling APA,shedding new light on the roles of the m6A modification during RNA 3'-end processing in nitrate metabolism.