Erratum

Genes & Development 20: 2902–2911 (2006)

Canalization of auxin flow by Aux/IAA-ARF-dependent feedback regulation of PIN polarity

Michael Sauer, Jozef Balla, Christian Luschnig, Justyna Wisniewska, Vilém Reinöhl, Jirí Friml, and Eva Benková

The homozygous T-DNA insertion line SALK_062511 (arf17-511), which we refer to in our above-mentioned paper as arf17, suggesting nullizygosity, had been previously characterized and found to be an overexpressor, instead of a knockout. Therefore, the following reference should have been included:

Sorin, C., Bussell, J.D., Camus, I., Ljung, K., Kowalczyk, M., Geiss, G., McKhann, H., Garcion, C., Vaucheret, H., Sandberg, G., et al. 2005. Auxin and light control of adventitious rooting in Arabidopsis require ARGONAUTE1. Plant Cell 17: 1343–1359.

We were unaware of this result and apologize to Sorin et al. for our oversight. We re-examined the expression of ARF17 in arf17-511 roots (Sorin et al. had only used above-ground material in their analyses) by semiquantitative RT–PCR and indeed found an overexpression of ARF17 also in the roots. The reduced PIN1 lateralization after auxin treatment, which we reported for the triple combination of arf7 ARF17ox arf19, compared with double arf7 arf19, is actually in line with microarray data (our unpublished results) in which we found ARF17 transcript up-regulated in transgenic lines harbouring a stabilized axr3/IAA17; these plants fail to lateralize PIN1 after auxin treatment. This suggests that an up-regulation of ARF17 expression is in line with reduced PIN1 lateralization. On the other hand, expression levels of ARF7, ARF16,and ARF19 were reduced in the transgenics with stabilized axr3/IAA17. In line with this, we observed reduced lateralization in the true null arf7 arf16 arf19 triple mutants. (Normalized lateral-to-basal ratio was 1038, compared with 1348 for wild type; P < 0.001).