Project name: Solanum lycopersicum

Description: 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 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 (TPL) corepressor and with several transcription factors, providing specificity for its repressive functions. A sub-group of flowering-associated genes are 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 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.Overall design: The tomato ltm mutant SAM was compared to WT SAM at the same vegetative stage. WT SAM at floral transition was compared to vegetative WT SAM. Experiments were done in two repeats for each condition.

Data type: Transcriptome or Gene expression

Sample scope: Multiisolate

Relevance: Agricultural

Last updated: 2017-02-21