CaFT1 is the FLOWERING LOCUS T ortholog in Coffea sp. L

32 33 The behavior of florigen(s) and environment-influenced regulatory pathways that control 34 flowering in tropical perennials with complex phenological cycles is poorly understood. 35 Understanding the mechanisms underlying this process is important for food production in the 36 face of climate change. To explore this, homologs of Arabidopsis florigen FLOWERING LOCUS 37 T (CaFT1) and environment-related regulators CONSTANS (CO), PHYTOCHROME 38 INTERACTING FACTOR 4 (PIF4) and FLOWERING LOCUS C (FLC) were isolated from 39 Coffea sp. L. (Rubiaceae). Overexpression of CaFT1 in Arabidopsis showed typical early40 flowering and yeast two hybrid studies indicated CaFT1 binding to bZIP floral regulator, FD, 41 demonstrates that CaFT1 is a coffee orthologue of florigen. Expression of CaFT1 and floral 42 regulators were evaluated over one year using three contrasting genotypes: two C. arabica and 43 one C. canephora. All genotypes showed active CaFT1 transcription from February until 44 October, indicating a potential window for floral induction. CaCO expression, as expected, 45 varied over the day period and monthly with day length, whereas expression of temperature46 responsive homologs, CaFLC and CaPIF4, did not correlate with temperature changes. Using 47 coffee as a model, we suggest a continuum of floral induction that allows different starting points 48 for floral activation, which explains developmental asynchronicity and prolonged anthesis events 49 in tropical perennial species. 50 51