Cytokinin Response Factor 6 Represses Cytokinin-Associated Genes during Oxidative Stress  . Issue 2 (22nd August 2016)

• Record Type: Journal Article
• Authors: Zwack, Paul J.; De Clercq, Inge; Howton, Timothy C.; Hallmark, H. Tucker; Hurny, Andrej; Keshishian, Erika A.; Parish, Alyssa M.; Benkova, Eva; Mukhtar, M. Shahid; Van Breusegem, Frank; Rashotte, Aaron M.
• Is Part Of: Plant physiology. Volume 172:Issue 2(2016)
• Page Start: 1249
• Page End: 1258
• Publication Date: 2016-08-22
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.16.00415
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : Arabidopsis CYTOKININ RESPONSE FACTOR 6 represses a module of cytokinin-associated genes during exposure to oxidative stress. Abstract: Cytokinin is a phytohormone that is well known for its roles in numerous plant growth and developmental processes, yet it has also been linked to abiotic stress response in a less defined manner. Arabidopsis ( Arabidopsis thaliana ) Cytokinin Response Factor 6 (CRF6) is a cytokinin-responsive AP2/ERF-family transcription factor that, through the cytokinin signaling pathway, plays a key role in the inhibition of dark-induced senescence. CRF6 expression is also induced by oxidative stress, and here we show a novel function for CRF6 in relation to oxidative stress and identify downstream transcriptional targets of CRF6 that are repressed in response to oxidative stress. Analysis of transcriptomic changes in wild-type and crf6 mutant plants treated with H2 O2 identified CRF6-dependent differentially expressed transcripts, many of which were repressed rather than induced. Moreover, many repressed genes also show decreased expression in 35S:CRF6 overexpressing plants. Together, these findings suggest that CRF6 functions largely as a transcriptional repressor. Interestingly, among the H2 O2 repressed CRF6-dependent transcripts was a set of five genes associated with cytokinin processes: (signaling) ARR6, ARR9, ARR11, (biosynthesis) LOG7, and (transport) ABCG14. We have examined mutants of these cytokinin-associated target genes to reveal novel connections to oxidative stress. Further examination of CRF6-DNA interactions indicated that CRF6 may regulate its targets both directly and indirectly. Together, this shows that CRF6 functions during oxidative stress as a negative regulator to control this cytokinin-associated module of CRF6-dependent genes and establishes a novel connection between cytokinin and oxidative stress response.