The SELF-PRUNING gene of tomato regulates vegetative to reproductive switching of sympodial meristems and is the ortholog of CEN and TFL1.
Vegetative and reproductive phases alternate regularly during sympodial growth in tomato. In wild-type 'indeterminate' plants, inflorescences are separated by three vegetative nodes. In 'determinate' plants homozygous for the recessive allele of the SELF-PRUNING (SP) gene, sympodial segments develop progressively fewer nodes until the shoot is terminated by two consecutive inflorescences. We show here that the SP gene is the tomato ortholog of CENTRORADIALIS and TERMINAL FLOWER1, genes which maintain the indeterminate state of inflorescence meristems in Antirrhinum and Arabidopsis respectively. The sp mutation results in a single amino acid change (P76L), and the mutant phenotype is mimicked by overexpressing the SP antisense RNA. Ectopic and overexpression of the SP and CEN transgenes in tomato rescues the 'indeterminate' phenotype, conditions the replacement of flowers by leaves in the inflorescence and suppresses the transition of the vegetative apex to a reproductive shoot. The SELF-PRUNING gene is expressed in shoot apices and leaves from very early stages, and later in inflorescence and floral primordia as well. This expression pattern is similar to that displayed by the tomato ortholog LEAFY and FLORICAULA. Comparison of the sympodial, day-neutral shoot system of tomato and the monopodial, photoperiod-sensitive systems of Arabidopsis and Antirrhinum suggests that flowering genes that are required for the processing of floral induction signals in Arabidopsis and Antirrhinum are required in tomato to regulate the alternation between vegetative and reproductive cycles in sympodial meristems.
Pnueli
L
L
Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Carmel-Goren
L
L
Hareven
D
D
Gutfinger
T
T
Alvarez
J
J
Ganal
M
M
Zamir
D
D
Lifschitz
E
E
D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins; D001483:Base Sequence; D015870:Gene Expression; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development; D018519:Meristem / Q000033:anatomy & histology / Q000254:growth & development*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D018520:Plant Shoots / Q000033:anatomy & histology / Q000254:growth & development*; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors
D029681:Arabidopsis Proteins; C098219:CEN protein, Antirrhinum majus; C083654:FLO protein, Antirrhinum majus; C074747:LFY protein, Arabidopsis; D010940:Plant Proteins; C112956:SP protein, Lycopersicon esculentum; C102864:TFL1 protein, Arabidopsis; D014157:Transcription Factors