Promoting flowering, lateral shoot outgrowth, leaf development, and flower abscission in tobacco plants overexpressing cotton FLOWERING LOCUS T (FT)-like gene GhFT1

Abstract

FLOWERING LOCUS T (FT) encodes a mobile signal protein, recognized as major component of florigen, which has a central position in regulating flowering, and also plays important roles in various physiological aspects. A mode is recently emerging for the balance of indeterminate and determinate growth, which is controlled by the ratio of FT-like and TERMINAL FLOWER 1 (TFL1)-like gene activities, and has a strong influence on the floral transition and plant architecture. Orthologs of GhFT1 was previously isolated and characterized from Gossypium hirsutum. We demonstrated that ectopic overexpression of GhFT1 in tobacco, other than promoting flowering, promoted lateral shoot outgrowth at the base, induced more axillary bud at the axillae of rosette leaves, altered leaf morphology, increased chlorophyll content, had higher rate of photosynthesis and caused flowers abscission. Analysis of gene expression suggested that flower identity genes were significantly upregulated in transgenic plants. Further analysis of tobacco FT paralogs indicated that NtFT4, acting as flower inducer, was upregulated, whereas NtFT2 and NtFT3 as flower inhibitors were upregulated in transgenic plants under long-day conditions, but downregulated under short-day conditions. Our data suggests that sufficient level of transgenic cotton FT might disturb the balance of the endogenous tobacco FT paralogs of inducers and repressors and resulted in altered phenotype in transgenic tobacco, emphasizing the expanding roles of FT in regulating shoot architecture by advancing determine growth. Manipulating the ratio for indeterminate and determinate growth factors throughout FT-like and TFL1-like gene activity holds promise to improve plant architecture and enhance crop yield.

Overexpression of Arabidopsis FLOWERING LOCUS T (FT) gene improves floral development in cassava (Manihot esculenta, Crantz)

“…In contrast to flower initiation, flower prolificacy, and branching, flower and leaf organogenesis was not apparently affected by FT overexpression in cassava, as leaves and flowers were the same size and shape as in non-transformed plants ( Fig 4 ). This agrees with the outcome in most reported studies, but contrasts with findings in FT -overexpressing lines of apple, which had more numerous petals, fewer stamens, and no pistils [ 16 ], and in FT overexpression lines of tobacco where there was also altered leaf morphology, increased leaf chlorophyll content and photosynthetic rates, and flower abscission [ 11 ].…”

“…Increased branching has also been reported in transgenic plants overexpressing FT in tobacco ( Nicotiana spp.) [ 11 ] and Eucalyptus [ 15 ]. In contrast to flower initiation, flower prolificacy, and branching, flower and leaf organogenesis was not apparently affected by FT overexpression in cassava, as leaves and flowers were the same size and shape as in non-transformed plants ( Fig 4 ).…”

“…There is evidence that FT signaling plays a role in photoperiodic and developmental regulation in species closely related to cassava. In Barbados nut ( Jatropha curcas ), which like cassava is in the Euphorbiaceae family, an FT homolog is primarily expressed in the reproductive organs and is thought to play a role in flower induction [ 10 , 11 ]. In leafy spurge ( Euphorbia esula ), long photoperiods (16 h light) stimulates accumulation of FT homologs in a diurnal manner consistent with flower induction.…”

ALSV Vector Substantially Shortens Generation Time of Horticultural Plants

“…The name of the gene controlling plant flowering is 'Flowering locus T' (FT). Initially, plant biologists aimed to express the FT gene in crops by transformation, which actually accelerated flowering [3][4][5][6][7]. This suggested the functional use of FT in controlling flowering time, but transgenic plants are not typically applicable to crop production.…”

The role of trehalose 6-phosphate in shoot branching – local and non-local effects on axillary bud outgrowth in arabidopsis rosettes

“…In arabidopsis, 97 FT and its close homologue, TWIN SISTER OF FT (TSF), interact with the branching repressor BRC1 in 98 axillary buds (Niwa et al, 2013). In rice (Oryza sativa), a homologue of FT has been shown to regulate 99 tillering (Tsuji et al, 2015), and there is evidence for an increase in branching mediated by up-100 regulation of FT in tomato (Solanum lycopersicum; Weng et al, 2016) or expression of a heterologous 101 FT in tobacco (Nicotiana tabacum; Li et al, 2015). In pea, one FT homologue, GIGAS, has also been 102 implicated in the regulation of bud outgrowth (Beveridge and Murfet, 1996;Hecht et al, 2011).…”