Abstract
Boron is among the essential elements for higher plants. Rice plants grow normally with relatively low supply of boron and boron concentrations in aerial portions are generally lower than those of dicots, though they are also susceptible to boron deficiency. To reveal the molecular mechanisms of boron transport in rice, we analyzed rice genes similar to BOR1. Four BOR1-like genes were found in the genome of rice and were named OsBOR1, 2, 3 and 4.
When expressed in yeast, OsBOR1-3 reduced concentration of boron in the cells suggesting that they are efflux transporter of boron. Tissue specificity of expression of the homologous genes differ among the OsBOR genes, suggesting differential roles of individual transporters. Analysis of several Tos17 tagged lines corresponding to the OsBOR genes suggest important role of OsBOR genes in boron transport and growth under boron-limiting conditions.
