Figure 8.

Schematic presentation of role of OsNIP3;1 in uptake and distribution of B in rice. A, Role of OsNIP3;1 in B uptake. OsNIP3;1 polarly localized at the distal side of cells in the root tips locally contributes to B influx into the cells. In the root mature region, Lsi1 polarly localized at the distal side of exodermis and endodermis mediates B influx to the root cells. OsBOR1 is proposed to be involved in B efflux from the root cells. B, Role of OsNIP3;1 in preferential distribution of B to developing tissues. OsNIP3;1 polarly localized at the xylem transfer cells of enlarged vascular bundle mediates unloading of B from the xylem for intervascular transfer. Efflux B transporter for the intervascular transfer is unidentified. OsNIP3;1 located at the phloem cell of diffuse vascular bundle also facilitates B influx to the phloem for preferential distribution. OsNIP3;1 is regulated at both transcriptional and protein level in response to environmental B change.