The Cloning and Functional Study of FLOWERING LOCUS T(FT) Homologous Genes from Litchi
|Keywords||Litchi chinensis FLOWERING LOCUS T(FT)homologousgene cDNA cloning expression pattern gene function|
Plant FLOWERING LOCUS T (FT) homologous gene plays a important role in the flower forming. Recently FT protein has been proved to be florigen. In order to explore the molecular of flowering organ forming and further understanding the flowering mechanism of litchi, two FT homologous genes have been cloned from litchi and their bioinformatics and expression pattern analysis were studied. Meanwhile, the function of two genes have been preliminarily identified in this study. The main results were summarized as follows:1. The cloning and bioinformatics analysis of litchi FT homologous genes.Two full-length cDNA sequences of FT homologous genes were first cloned with RT-PCR from Litchi, which were named as LcFT1and LcFT2(GenBank accession No.JN214350、 JN214351). The open reading frame (ORF) of LcFT1gene is522bp, encoding a protein of174amino acids, with estimated molecular weight and isoelectric point of19.65KD and8.68respectively. The ORF of LcFT2gene is522bp, encoding a protein of174amino acids too, with estimated molecular weight and isoelectric point of19.56KD and7.34respectively. The prediction of protein secondary structure shows that LcFT1and LcFT2proteins all have4a helices and10β sheets. The homologous analysis indicates that LcFT1and LcFT2genes have a range of72%to82%identity in nucleotide sequence with other plants.2. The expression analysis of litchi FT homologous genes. Two full-length cDNA sequences of Actin homologous genes were first cloned with RT-PCR from Litchi, which were named as LcActin4and LcActin7(GenBank accession No. HQ588865、HQ588866). Expression analysis by RT-PCR indicted that LcFT1and LcFT2genes expressed only in leaf during ’Sanyuehong’ Litchi flower bud differentiation period, moreover, they expressed the highest in mature leaf.3. The functional identification of Litchi FT homologous genes. The35S::LcFTl and35S::LcFT2expression vectors were constructed and introduced into’Yunyan97’tobacco by Agrobacterium tumefaciens respectively. The results showed that transgenic tobacco plants with the LcFT1or LcFT2were significantly early flowering, their flower bud differentiation occurred at about16and30days after transplantation respectively, however, lower bud differentiation of the non-transgenic control was about85days after transplantation. the result showed that LcFT1and LcFT2genes could play a important role in the flower forming of Litchi, while there was a little difference in their functions of the two genes.