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Functional analysis of alternative splicing of the FLOWERING LOCUS T orthologous gene in Chrysanthemum morifolium

View Article: PubMed Central - PubMed

ABSTRACT

As the junction of floral development pathways, the FLOWERING LOCUS T (FT) protein called ‘florigen’ plays an important role in the process of plant flowering through signal integration. We isolated four transcripts encoding different isoforms of a FT orthologous gene CmFTL1, from Chrysanthemum morifolium cultivar ‘Jimba’. Sequence alignments suggested that the four transcripts are related to the intron 1. Expression analysis showed that four alternative splicing (AS) forms of CmFTL1 varied depending on the developmental stage of the flower. The functional complement experiment using an Arabidopsis mutant ft-10 revealed that the archetypal and AS forms of CmFTL1 had the function of complementing late flower phenotype in different levels. In addition, transgenic confirmation at transcript level showed CmFTL1 and CmFTL1ast coexist in the same tissue type at the same developmental stage, indicating a post-transcriptional modification of CmFTL1 in Arabidopsis. Moreover, ectopic expression of different AS forms in chrysanthemum resulted in the development of multiple altered phenotypes, varying degrees of early flowering. We found that an alternative splicing form (CmFTL1-astE134) without the exon 2 lacked the ability causing the earlier flower phenotype. The evidence in this study indicates that complex alternative processing of CmFTL1 transcripts in C. morifolium may be associated with flowering regulation and hold some potential for biotechnical engineering to create early-flowering phenotypes in ornamental cultivars.

No MeSH data available.


Related in: MedlinePlus

The nucleotide sequences of CmFTL1 and its AS products. (a) Sequence alignment of CmFTL1 cDNA and its AS products; asterisks indicate separation of the four exons. (b) The genomic sequence of a segment of CmFTL1. Exons are shown boxed. The letters highlighted in grey indicate the AS sites. The bold letters indicate the initiation (ATG) and the termination (TAA) codons. (c) Processing of CmFTL1. Horizontal lines indicate the 5′ and 3′ UTRs. The coding regions are shown as grey-stippled boxes and the introns as white boxes; dotted lines indicate unknown introns. The vertical lines in the white boxes indicate the AS sites.
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fig1: The nucleotide sequences of CmFTL1 and its AS products. (a) Sequence alignment of CmFTL1 cDNA and its AS products; asterisks indicate separation of the four exons. (b) The genomic sequence of a segment of CmFTL1. Exons are shown boxed. The letters highlighted in grey indicate the AS sites. The bold letters indicate the initiation (ATG) and the termination (TAA) codons. (c) Processing of CmFTL1. Horizontal lines indicate the 5′ and 3′ UTRs. The coding regions are shown as grey-stippled boxes and the introns as white boxes; dotted lines indicate unknown introns. The vertical lines in the white boxes indicate the AS sites.

Mentions: We used RACE strategies to clone the CmFTL genes of C. morifolium cultivar ‘Jimba’. The products of CmFTL1 were electrophoresed through 2% agarose gels and cloned into the sequencing vector. Different sizes of CmFTL1 cDNA products were obtained. Analysis of the sequences revealed that the CmFTL1 had at least five different alternatively spliced transcripts. Compared with the normal full-length CmFTL1 transcript, two of the alternatively spliced products (CmFTL1astIn1-1, CmFTL1astIn1-2) contained the different lengths of the intron and two transcripts (CmFTL1astE134 and CmFTL1astIn1-3) lacked exons (Figure 1a).


Functional analysis of alternative splicing of the FLOWERING LOCUS T orthologous gene in Chrysanthemum morifolium
The nucleotide sequences of CmFTL1 and its AS products. (a) Sequence alignment of CmFTL1 cDNA and its AS products; asterisks indicate separation of the four exons. (b) The genomic sequence of a segment of CmFTL1. Exons are shown boxed. The letters highlighted in grey indicate the AS sites. The bold letters indicate the initiation (ATG) and the termination (TAA) codons. (c) Processing of CmFTL1. Horizontal lines indicate the 5′ and 3′ UTRs. The coding regions are shown as grey-stippled boxes and the introns as white boxes; dotted lines indicate unknown introns. The vertical lines in the white boxes indicate the AS sites.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120556&req=5

fig1: The nucleotide sequences of CmFTL1 and its AS products. (a) Sequence alignment of CmFTL1 cDNA and its AS products; asterisks indicate separation of the four exons. (b) The genomic sequence of a segment of CmFTL1. Exons are shown boxed. The letters highlighted in grey indicate the AS sites. The bold letters indicate the initiation (ATG) and the termination (TAA) codons. (c) Processing of CmFTL1. Horizontal lines indicate the 5′ and 3′ UTRs. The coding regions are shown as grey-stippled boxes and the introns as white boxes; dotted lines indicate unknown introns. The vertical lines in the white boxes indicate the AS sites.
Mentions: We used RACE strategies to clone the CmFTL genes of C. morifolium cultivar ‘Jimba’. The products of CmFTL1 were electrophoresed through 2% agarose gels and cloned into the sequencing vector. Different sizes of CmFTL1 cDNA products were obtained. Analysis of the sequences revealed that the CmFTL1 had at least five different alternatively spliced transcripts. Compared with the normal full-length CmFTL1 transcript, two of the alternatively spliced products (CmFTL1astIn1-1, CmFTL1astIn1-2) contained the different lengths of the intron and two transcripts (CmFTL1astE134 and CmFTL1astIn1-3) lacked exons (Figure 1a).

View Article: PubMed Central - PubMed

ABSTRACT

As the junction of floral development pathways, the FLOWERING LOCUS T (FT) protein called ‘florigen’ plays an important role in the process of plant flowering through signal integration. We isolated four transcripts encoding different isoforms of a FT orthologous gene CmFTL1, from Chrysanthemum morifolium cultivar ‘Jimba’. Sequence alignments suggested that the four transcripts are related to the intron 1. Expression analysis showed that four alternative splicing (AS) forms of CmFTL1 varied depending on the developmental stage of the flower. The functional complement experiment using an Arabidopsis mutant ft-10 revealed that the archetypal and AS forms of CmFTL1 had the function of complementing late flower phenotype in different levels. In addition, transgenic confirmation at transcript level showed CmFTL1 and CmFTL1ast coexist in the same tissue type at the same developmental stage, indicating a post-transcriptional modification of CmFTL1 in Arabidopsis. Moreover, ectopic expression of different AS forms in chrysanthemum resulted in the development of multiple altered phenotypes, varying degrees of early flowering. We found that an alternative splicing form (CmFTL1-astE134) without the exon 2 lacked the ability causing the earlier flower phenotype. The evidence in this study indicates that complex alternative processing of CmFTL1 transcripts in C. morifolium may be associated with flowering regulation and hold some potential for biotechnical engineering to create early-flowering phenotypes in ornamental cultivars.

No MeSH data available.


Related in: MedlinePlus