Abstract
Boron (B) is both essential and toxic to plant growth. Through transcriptome and semi-quantitative PCR analysis with low- and high-B treated Arabidopsis thaliana, we identified nine genes whose transcript accumulations were induced in roots or rosette leaves under boron excess. These genes included a heat-shock protein and MATE efflux family transporters. We also obtained T-DNA insertion lines in more than ten genes whose expressions were induced by low- or high-B treatetments. Among the lines, root growth of wrky6-3 carrying T-DNA insertion in the third exon of WRKY6 gene was poorer than that of wild-type under boron deficiency but not under a control condition. We also confirmed that boron deficiency-specific retardation of root elongation of wrky6-1 and wrky6-2 (kind gift from I. Somssich), establishing role of WRKY6 in low-B response. Promoter activity and transcript accumulation of WRKY6 was induced near the root tip under the boron deficiency.
