CaFT-LIKE is a flowering promoter in pepper and functions as florigen in tomato

Abstract

We identified a pepper late-flowering mutant that is disrupted in the sequence of CaFT-LIKE, the ortholog of tomato SINGLE FLOWER TRUSS (SFT). Heterologous expression in tomato indicated that CaFT-LIKE has a conserved function as a flowering promoter and can rescue the wild-type phenotype of the tomato sft mutant. CaFT-LIKE confers a graft-transmissible signal for flowering initiation in tomato, implicating its function as a florigen. To test the relationship between CaFT-LIKE and FASCICULATE (FA), the ortholog of tomato SELF PRUNING (SP), we constructed the double mutant Caft-like fa. The phenotype of Caft-like fa resembled that of Caft-like, indicating epistasis of Caft-like over fa in controlling flowering time and sympodial shoot structure. To examine the association between the expression pattern of flowering genes and natural variation in flowering time, the expression levels of CaFT-LIKE and the flowering repressor CaAP2 were determined in a panel of early-flowering cultivars and late-flowering landraces and wild accessions. Strong positive and negative correlations between flowering time and expression levels of CaAP2 and CaFT-LIKE, respectively, were observed, indicating that high-expression alleles of CaFT-LIKE and low-expression alleles of CaAP2 were selected for early flowering during pepper domestication and breeding.