WRKY6 is involved in the response to boron deficiency inArabidopsis thaliana

Abstract

Boron (B) is one of the essential nutrients for plant growth and reproduction. Transcriptome analyses have identified genes regulated by B deficiency, but their function mostly remains elusive. To identify the functions of B deficiency-inducible genes, T-DNA insertion mutants of 10 B deficiency-induced genes were obtained, and their growth properties in response to B conditions were examined. Among the lines examined, mutants of the transcription factor WRKY6 showed growth defect compared with the wild-type under B deficiency, but not under normal conditions. This growth defect was commonly observed among three independently isolated wrky6 mutants. There was no significant difference in B concentration between wrky6-3 and the wild-type. Promoter activity of WRKY6 was induced around the root tip under B deficiency. These results established that WRKY6 is a low-B-induced transcription factor gene that is essential for normal root growth under low-B conditions. Transcriptome analysis around the root tip identified WRKY6-regulated genes under B deficiency. Our findings represent the first identification of a transcription factor involved in the response to B deficiency.

Transcriptional Profiling Reveals Adaptive Responses to Boron Defi ciency Stress in Arabidopsis

“…Previously, only WRKY6 had been reported as a transcription factor involved in the response to B defi ciency. Levels of the WRKY6 transcript were induced up to two-fold by low B stress, and this induction was essential for normal root growth under low B conditions (Kasajima et al, 2010). In our experiments, expression of WRKY6 was also up-regulated approximately two-fold after 3 h of short-term B deprivation.…”

The rice transcription factor OsWRKY47 is a positive regulator of the response to water deficit stress

“…However, some interesting examples are available in the literature; AtWRKY18 which is involved in ABA signaling and salt tolerance (Chen et al 2010;Shang et al 2010) binds the sequence (C/A)TTGAC(T/G). AtWRKY6, a negative regulator of the response to low Pi levels and a positive regulator to low brassinosteroid levels (Chen et al 2009;Kasajima et al 2010), binds specifically the sequence GTTGACC, a sequence similar to that bound by OsWRKY47 (Ciolkowski et al 2008). The same cis-element bound by OsWRKY47 is also bound by AtWRKY11 (Ciolkowski et al 2008) which e Cysteine-rich repeat secretory protein (CRRSP) transcript levels in WT and in mutant Osw47-1 plants.…”

Increased root hair density by loss of WRKY6 in Arabidopsis thaliana

“…WRKY6 thus appears not only to repress phosphate transporters, but also root hairs. It is strongly up-regulated by a toxic arsenate pulse (Castrillo et al, 2013) and under boron deficiency (Kasajima et al, 2010), further establishing the link to nutrition. Several nutrients thus affected WRKY6.…”