Present address: Institut für Angewandte Genetik, Molekulare Entwicklungsbiologie der Pflanzen, Albrecht-Thaer Weg 6, 14195 Berlin, Germany.
Point mutations in Arabidopsis Cullin1 reveal its essential role in jasmonate response
Article first published online: 4 APR 2005
The Plant Journal
Volume 42, Issue 4, pages 514–524, May 2005
How to Cite
Ren, C., Pan, J., Peng, W., Genschik, P., Hobbie, L., Hellmann, H., Estelle, M., Gao, B., Peng, J., Sun, C. and Xie, D. (2005), Point mutations in Arabidopsis Cullin1 reveal its essential role in jasmonate response. The Plant Journal, 42: 514–524. doi: 10.1111/j.1365-313X.2005.02394.x
- Issue published online: 4 APR 2005
- Article first published online: 4 APR 2005
- Received 16 November 2004; revised 23 January 2005; accepted 9 February 2005.
The SKP1-Cullin/Cdc53-F-box protein ubiquitin ligases (SCF) target many important regulatory proteins for degradation and play vital roles in diverse cellular processes. In Arabidopsis there are 11 Cullin members (AtCUL). AtCUL1 was demonstrated to assemble into SCF complexes containing COI1, an F-box protein required for response to jasmonates (JA) that regulate plant fertility and defense responses. It is not clear whether other Cullins also associate with COI1 to form SCF complexes, thus, it is unknown whether AtCUL1, or another Cullin that assembles into SCFCOI1 (even perhaps two or more functionally redundant Cullins), plays a major role in JA signaling. We present genetic and physiological data to directly demonstrate that AtCUL1 is necessary for normal JA responses. The homozygous AtCUL1 mutants axr6-1 and axr6-2, the heterozygous mutants axr6/AXR6, and transgenic plants expressing mutant AtCUL1 proteins containing a single amino acid substitution from phenylalanine-111 to valine, all exhibit reduced responses to JA. We also demonstrate that ax6 enhances the effect of coi1 on JA responses, implying a genetic interaction between COI1 and AtCUL1 in JA signaling. Furthermore, we show that the point mutations in AtCUL1 affect the assembly of COI1 into SCF, thus attenuating SCFCOI1 formation.