Identification of novel Arabidopsis thaliana genes which are induced by high levels of boron

Boron (B) is an essential nutrient for plants but is toxic at high levels. We performed transcriptome analysis under conditions of both low and high B in Arabidopsis thaliana. There is a positive correlation between the levels of gene induction by low and high B, suggesting that common pathways operate during these responses. Induction by high B was also confirmed for nine genes in an independent experiment. Transcripts of At1g03770 (transcription factor) and At5g57340 were found to be elevated in roots, whereas At2g04040, At2g04050, At2g04070 (all encoding multidrug and toxic compound extrusion transporters), At1g32870 (transcription factor), At5g51440 (heat shock protein-like), At2g41730 and At2g21640 are induced in the shoots. The accumulation of both At2g04050 and At5g51440 transcripts was further found to be elevated by more than 100-fold after two days of high B treatment. Our findings thus represent the first identification of high B- induced genes.