Angiosperm Flora of India

The Arabidopsis O-Linked N-Acetylglucosamine Transferase SPINDLY Interacts with Class I TCPs to Facilitate Cytokinin Responses in Leaves and Flowers

Publication Type:Journal Article
Year of Publication:2012
Authors:Steiner, E, Efroni, I, Gopalraj, M, Saathoff, K, Tseng, T-seung, Kieffer, M, Eshed, Y, Olszewski, N, Weiss, D
Journal:The Plant Cell
Date Published:2012
ISBN Number:10404651

O-linked N-acetylglucosamine (O-GlcNAc) modifications regulate the posttranslational fate of target proteins. The Arabidopsis thaliana O-GlcNAc transferase (OGT) SPINDLY (SPY) suppresses gibberellin signaling and promotes cytokinin (CK) responses by unknown mechanisms. Here, we present evidence that two closely related class I TCP transcription factors, TCP14 and TCP 15, act with SPY to promote CK responses. TCP14 and TCP15 interacted with SPY in yeast two-hybrid and in vitro pulldown assays and were O-GlcNAc modified in Escherichia coli by the Arabidopsis OGT, SECRET AGENT. Overexpression of TCP14 severely affected plant development in a SPV-dependent manner and stimulated typical CK morphological responses, as well as the expression of the CK-regulated gene RESPONSE REGULATORS. TCP14 also promoted the transcriptional activity of the CK-induced mitotic factor CYCLIN B1;2. Whereas TCPW-overexpressing plants were hypersensitive to CK, spy and tcp14 tcp15 double mutant leaves and flowers were hyposensitive to the hormone. Reducing CK levels by overexpressing CK OXIDASE/DEHYDROGENASE3 suppressed the TCP14 overexpression phenotypes, and this suppression was reversed when the plants were treated with exogenous CK. Taken together, we suggest that responses of leaves and flowers to CK are mediated by SPY-dependent TCP14 and TCP15 activities.

Short Title:The Plant Cell
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