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

Li C, Zhang Y, Zhang K, Guo D, Cui B, Wang X, Huang X - Front Plant Sci (2015)

Bottom Line: Analysis of gene expression suggested that flower identity genes were significantly upregulated in transgenic plants.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.

View Article: PubMed Central - PubMed

Affiliation: Plant Genomics Laboratory, College of Life Sciences, Shihezi University Shihezi, China.

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.

No MeSH data available.


Related in: MedlinePlus

Phenotype analysis of transgenic tobacco (Nicotiana tabacum) lines that ectopically expressed GhFT1. (A) Appearance of 41 days wild-type (WT) tobacco and 35S::GhFT1 transgenic tobacco line 1 and line 2 grown in phytotron under long-day (LD; 16 h light/8 h dark) conditions. (B) Detection of GhFT1 expression by quantitative real-time PCR (qRT-PCR) in the 35S::GhFT1 transgenic lines and WT control under LD conditions. (C) Appearance of 54 days WT tobacco and 35S::GhFT1 transgenic tobaccos line 15 and line 16 grown in phytotron under short-day (SD; 8 h light/16 h dark) conditions. (D) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under SD conditions. (E) Appearance of 53 days WT tobacco and 5.7kbAtFTpro::GhFT1 transgenic tobacco lines grown in phytotron under SD conditions. (F) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under LD conditions. Scale bars: 3.0 cm. Values are mean ± SE of results from three independent replicates (n = 3).
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Figure 2: Phenotype analysis of transgenic tobacco (Nicotiana tabacum) lines that ectopically expressed GhFT1. (A) Appearance of 41 days wild-type (WT) tobacco and 35S::GhFT1 transgenic tobacco line 1 and line 2 grown in phytotron under long-day (LD; 16 h light/8 h dark) conditions. (B) Detection of GhFT1 expression by quantitative real-time PCR (qRT-PCR) in the 35S::GhFT1 transgenic lines and WT control under LD conditions. (C) Appearance of 54 days WT tobacco and 35S::GhFT1 transgenic tobaccos line 15 and line 16 grown in phytotron under short-day (SD; 8 h light/16 h dark) conditions. (D) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under SD conditions. (E) Appearance of 53 days WT tobacco and 5.7kbAtFTpro::GhFT1 transgenic tobacco lines grown in phytotron under SD conditions. (F) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under LD conditions. Scale bars: 3.0 cm. Values are mean ± SE of results from three independent replicates (n = 3).

Mentions: Our previous research showed that overexpression of cotton GhFT1 in Arabidopsis caused early flowering both LD and SD conditions (Guo et al., 2015). To explore the potential of GhFT1 in the regulation of flowering in tobacco, this gene was overexpressed in N. tabacum under the control of the strong and constitutive cauliflower mosaic virus (CaMV) 35S promoter by transformation with 35S::GhFT1 construct (Supplementary Figure S1B). We obtained numerous transgenic lines from two times of independent transform assays, and all of them were confirmed by PCR (data was not provided). The majority of 35S::GhFT1 primary transformants flowered much early than the WT, both in terms of time and the number of leaves before flowering (Supplementary Table S2). In the homozygous T3 plants, 14 showed significantly early flowering phenotype under LD (line 1 and line 2 are shown as an example in Figure 2A), and 12 also showed precocious flowering compared with the WT plants under SD conditions (line 15 and line 16 are shown as an example in Figure 2B). In LD conditions, the flowering time in the 35S::GhFT1 transgenic lines was 45.8 ± 4.8 days after sowing by producing 8 ± 0.7 leaves, compared with 106.3 ± 4.8 days by producing 16 ± 0.8 leaves in the WT (Supplementary Table S2). Likewise, under SD conditions, the flowering time of the 35S::GhFT1 transgenic lines was about 57.2 ± 4.9 days by producing 7 ± 0.9 leaves, compared with 94.5 ± 3.3 days by producing 15.7 ± 0.5 leaves in the WT siblings (Supplementary Table S2). In addition, transgenic lines had rapidly elongated internodes and reduced internodal length, and thereby developed dwarf stature when flowering than the controls under both conditions.


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

Li C, Zhang Y, Zhang K, Guo D, Cui B, Wang X, Huang X - Front Plant Sci (2015)

Phenotype analysis of transgenic tobacco (Nicotiana tabacum) lines that ectopically expressed GhFT1. (A) Appearance of 41 days wild-type (WT) tobacco and 35S::GhFT1 transgenic tobacco line 1 and line 2 grown in phytotron under long-day (LD; 16 h light/8 h dark) conditions. (B) Detection of GhFT1 expression by quantitative real-time PCR (qRT-PCR) in the 35S::GhFT1 transgenic lines and WT control under LD conditions. (C) Appearance of 54 days WT tobacco and 35S::GhFT1 transgenic tobaccos line 15 and line 16 grown in phytotron under short-day (SD; 8 h light/16 h dark) conditions. (D) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under SD conditions. (E) Appearance of 53 days WT tobacco and 5.7kbAtFTpro::GhFT1 transgenic tobacco lines grown in phytotron under SD conditions. (F) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under LD conditions. Scale bars: 3.0 cm. Values are mean ± SE of results from three independent replicates (n = 3).
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Figure 2: Phenotype analysis of transgenic tobacco (Nicotiana tabacum) lines that ectopically expressed GhFT1. (A) Appearance of 41 days wild-type (WT) tobacco and 35S::GhFT1 transgenic tobacco line 1 and line 2 grown in phytotron under long-day (LD; 16 h light/8 h dark) conditions. (B) Detection of GhFT1 expression by quantitative real-time PCR (qRT-PCR) in the 35S::GhFT1 transgenic lines and WT control under LD conditions. (C) Appearance of 54 days WT tobacco and 35S::GhFT1 transgenic tobaccos line 15 and line 16 grown in phytotron under short-day (SD; 8 h light/16 h dark) conditions. (D) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under SD conditions. (E) Appearance of 53 days WT tobacco and 5.7kbAtFTpro::GhFT1 transgenic tobacco lines grown in phytotron under SD conditions. (F) Detection of GhFT1 expression by qRT-PCR in the 35S::GhFT1 transgenic lines and WT control under LD conditions. Scale bars: 3.0 cm. Values are mean ± SE of results from three independent replicates (n = 3).
Mentions: Our previous research showed that overexpression of cotton GhFT1 in Arabidopsis caused early flowering both LD and SD conditions (Guo et al., 2015). To explore the potential of GhFT1 in the regulation of flowering in tobacco, this gene was overexpressed in N. tabacum under the control of the strong and constitutive cauliflower mosaic virus (CaMV) 35S promoter by transformation with 35S::GhFT1 construct (Supplementary Figure S1B). We obtained numerous transgenic lines from two times of independent transform assays, and all of them were confirmed by PCR (data was not provided). The majority of 35S::GhFT1 primary transformants flowered much early than the WT, both in terms of time and the number of leaves before flowering (Supplementary Table S2). In the homozygous T3 plants, 14 showed significantly early flowering phenotype under LD (line 1 and line 2 are shown as an example in Figure 2A), and 12 also showed precocious flowering compared with the WT plants under SD conditions (line 15 and line 16 are shown as an example in Figure 2B). In LD conditions, the flowering time in the 35S::GhFT1 transgenic lines was 45.8 ± 4.8 days after sowing by producing 8 ± 0.7 leaves, compared with 106.3 ± 4.8 days by producing 16 ± 0.8 leaves in the WT (Supplementary Table S2). Likewise, under SD conditions, the flowering time of the 35S::GhFT1 transgenic lines was about 57.2 ± 4.9 days by producing 7 ± 0.9 leaves, compared with 94.5 ± 3.3 days by producing 15.7 ± 0.5 leaves in the WT siblings (Supplementary Table S2). In addition, transgenic lines had rapidly elongated internodes and reduced internodal length, and thereby developed dwarf stature when flowering than the controls under both conditions.

Bottom Line: Analysis of gene expression suggested that flower identity genes were significantly upregulated in transgenic plants.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.

View Article: PubMed Central - PubMed

Affiliation: Plant Genomics Laboratory, College of Life Sciences, Shihezi University Shihezi, China.

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.

No MeSH data available.


Related in: MedlinePlus