Abstract
Among six BOR1 paralogs present in Arabidopsis thaliana genome, we studied roles of BOR6 and BOR7 in pollen development.
Transcripts of BOR6 and BOR7 were detected in flowers. Transgenic A.thaliana lines expressing GUS under the control of each gene promoter exhibited specific GUS staining in pollen and pollen tubes, suggesting that BOR6 and BOR7 are expressed in pollens.
Expression of BOR6 decreased B concentration of yeast cells, suggesting that BOR6 is a functional efflux B transporter, similar to the case of BOR1.
GFP fusion proteins of BOR6 and BOR7 are located at the tip of pollen tubes.
Experiment of pollen tube elongation in vitro under limited boron supply showed that length of pollen tubes of bor6-2/bor7-2, double T-DNA insertion mutant were shorter than those of the wild type.
These results suggest that BOR6 and BOR7 are B transporters important for pollen elongation under low boron supply.
