Functional Study Of MADS-box Gene SlFBP24 In Tomato

The MADS-box protein family is a large family of transcription factors widely distributed in higher plants,and it is mainly involved in the growth and development of plants,especially determining the properties of the floral organs.The floral development homeomorphic genes in dicotyledonous plants are classified into five major categories:A,B,C,D,and E according to the functions.These five groups of genes individually or jointly affect the morphological development of the four whorls of floral organ.Thus the ABCDE model of flower development was put forward.The genes in the ABCDE model mostly belong to MADS-box family.Moreover,there is a subfamily of MADS-box B genes,termed B-sister gene,which is also involved in regulating flower development,especially the development of female reproductive organs.However,there is a comprehensive study of Bs gene in Arabidopsis thaliana,and the understanding of the function of tomato Bs gene is still rare.Therefore,an amount of relevant research work is necessaryily.Tomato?Solanum lycopersicum?belongs to the herb of Solanaceae,which is widely grown as cultivated fruit and vegetable plant in China.At the same time,tomato is a traditional model plant for the study of fruit development and ripening.As Bs gene is reported mainly involved in regulating the development of female reproductive organs,which is important for the exploration of the development of tomato ovary and embryo.In this study,a tomato Bs gene SlFBP24?GenBank accession number:XM₀19211085?was identified based on Petunia FBP24 amino acid sequence.It is suggested that the protein encoded by the tomato SlFBP24 gene may belongs to the MIKC^C type of the MADS-box family by the phylogenetic comparison of the amino acid sequences with the MADS-box Bs genes of Arabidopsis and Petunia.The bioinformatics methods as well as real-time quantitative PCR technology was used to analyze the expression pattern of SlFBP24 gene,SlFBP24 gene was highly expressed in tomato floral organs,especially in the carpel,the expression is the highest.In order to explore the possible functions of SlFBP24 gene in flower development,RNAi technology and over-expression technology were used to silence or over-express SlFBP24 gene in wild type tomato AC++respectively,and obtained SlFBP24 gene silencing lines and over-expression lines.There was no phenotypic variation in the SlFBP24 silencing lines.In addition,seeds vigor was weakened in the over-expression lines in 10 to 40 times over-expression,and smaller floral organs,dwarf plants,pollen could not germinate,and failed fertility were exihibted in the over-expression lines which were overexpressed about 80 times.Real time q-PCR was used to detect the expression of the biosynthesis and response genes of gibberellin and auxin in the wild type and SlFBP24 over-expression lines.It showed that the transcriptional level of these genes changed,thus the changes in the contents of gibberellin and auxin may lead to the abnormal phenotype of the flower organs.