Effect of different B concentrations on localization and abundance of OsBOR1 and OsLsi1 proteins in rice roots. A–H, Localization of OsBOR1 and OsLsi1 in the root tip (A–D) and mature region (E–H) of crown roots. I and J, Signal intensity of OsBOR1 (I) and OsLsi1 (J). Transgenic seedlings (21-d-old) harboring Flag-OsLsi1 were pretreated with −B for 3 d, followed by exposing to 0, 0.3, 3, or 30 μM B for 6 h. The root tip region (3 mm from root tip) and mature root region (15 mm) of crown roots were sampled for double immunostaining of OsBOR1 and Flag-OsLsi1. Magenta color shows signal from OsBOR1, green color shows signal from Flag-OsLsi1, and blue color from cell wall autofluorescence and nuclei staind by DAPI. Scale bars indicate 50 µm. The signal intensities of OsBOR1 and OsLsi1 were quantified by LAS AF Lite software and the intensity relative to −B condition is shown. All pictures were taken under the same conditions. Data are means ± sd (n = 9–16). Different letters indicate significant differences at P < 0.05 by Tukey–Kramer’s test.