DBR1 is required for miRNA accumulation.

(A) Morphological phenotypes of Col-0 and dbr1-2 plants. DBR1-GFP dbr1-2, DBR1-RFP dbr1-2, and DBR1-Flag dbr1-2 represent rescued lines of dbr1-2 with different protein fusion constructs driven by the native DBR1 promoter. (B) miRNA northern blot analysis in Col-0, dbr1-2, and a dbr1-2 transgenic line containing the pDBR1::DBR1-RFP transgene (Compl). The numbers indicate the relative abundance of miRNAs among the three genotypes and represent the mean of three repeats (P < 0.05). U6 was used as a loading control. (C) Deep sequencing analysis of miRNAs in Col-0 and dbr1-2. Small RNA libraries were generated from inflorescences of two biological replicates. The normalized abundances of miRNAs were calculated as reads per ten million (RPTM), and log2-transformed ratios of dbr1-2/Col-0 were plotted. Each circle represents one miRNA. Thick lines indicate mean values. Rep1 and Rep2 denote replicate 1 and replicate 2, respectively.