Differential expression patterns of RBBI genes. Northernblot analysis of RBBI genes. Gene-specific 3′-UTR probes of RBBI2-1, RBBI2-2, RBBI2-3, RBBI2-4, RBBI3-1, RBBI3-2, RBBI3-3, and an 18S ribosomal RNA probe were used to detect the gene expression in the root (R), stem (S), leaf (L), flower (Fl), and young rice caryopsis (Fr).