Coordination of Meristem Doming and the Floral Transition by Late Termination, a Kelch Repeat Protein. Issue 4 (7th April 2017)

• Record Type: Journal Article
• Authors: Tal, Lior; Friedlander, Gilgi; Gilboa, Netta Segal; Unger, Tamar; Gilad, Shlomit; Eshed, Yuval
• Is Part Of: The Plant Cell. Volume 29:Issue 4(2017)
• Page Start: 681
• Page End: 696
• Publication Date: 2017-04-07
• DOI: 10.1105/tpc.17.00030
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : A kelch-containing repressor complex limits expression of the floral antagonist and meristem size promoter SELF PRUNING, thus restricting doming of the shoot apical meristem to the floral transition. Abstract: Enlargement and doming of the shoot apical meristem (SAM ) is a hallmark of the transition from vegetative growth to flowering. While this change is widespread, its role in the flowering process is unknown. The late termination ( ltm ) tomato ( Solanum lycopersicum ) mutant shows severely delayed flowering and precocious doming of the vegetative SAM . LTM encodes a kelch domain-containing protein, with no link to known meristem maintenance or flowering time pathways. LTM interacts with the TOPLESS corepressor and with several transcription factors that can provide specificity for its functions. A subgroup of flowering-associated genes is precociously upregulated in vegetative stages of ltm SAMs, among them, the antiflorigen gene SELF PRUNING ( SP ). A mutation in SP restored the structure of vegetative SAMs in ltm sp double mutants, and late flowering was partially suppressed, suggesting that LTM functions to suppress SP in the vegetative SAM . In agreement, SP -overexpressing wild-type plants exhibited precocious doming of vegetative SAMs combined with late flowering, as found in ltm plants. Strong flowering signals can result in termination of the SAM, usually by its differentiation into a flower. We propose that activation of a floral antagonist that promotes SAM growth in concert with floral transition protects it from such terminating effects.