Water Aoki Is (tetracentron) Flower Developmental Genes

Angiosperm(flower plants) is one of the major groups of extant spermatophyte and is different from the other groups which are no euanthia but with archegonia.Flower is an important propagation organ,as well as a pivotally innovative character.The morphologies of the flowers have been ceaselessly evolving along with the process of the evolution of the plants.The morphologies of the flowers in different groups of the angiosperm is quite various,especially the flowers of the basal eudicot which are much diverser.The evolution of morphologies of angiosperm,especially of the flowers,is closely related with the evolution of the MADS-box gene family.Phylogenetic analyses of angiosperm MADS-box genes suggest that the MADS-box gene subfamilies,which are responsible for the development of flowers,have undergone gene duplication events before the origin of the core eudicot.Consequently,the genes controlling the development of the flowers are distinctive in different groups of angiosperm and all have different evolutional history.It is significant to study the MADS-box genes controlling the flowers in Tetracentron as the link of basal angiosperm and core eudicot,for the futher understanding of the evolution of flowers in angiosperm and the molecular mechanism in the complexity and diveresty of flowers.Here,the MADS-box genes of Tetracentron are studied,to understand the evolution of the genes and discuss the systematic position of Tetracentron based on the MADS-box gene subfamilies.In our study,the total RNA of flower buds in different stages of Tetracentron sinensis was extracted,mRNA was purified,then cDNA was reverse transcribed and next step was 3'RACE. Following that,we joined the PCR products into the pGEM^?-T Easy Vector and transformed them into E.coli DH5α.Then the single-clones were sequenced.We analysed the gene sequences by the DNA software and BLAST,then classified and named them.Here,we gained 9 genes:TesFUL(FUL group);TesAP3-1,TesAP3-2(AP3 group);TesPI1,TesPI2(PI group);TesAG(AG group);TesSEP1 (SEP1 group);TesSEP3-1,TesSEP3-2(SEP3 group).We chose the sequences of the other groups in basal eudicot and the data we gained for phylogenetic analyses,the results as follow:1.The phylogenetic analyses of A-clade gene subfamily(FUL-like gene subfamily):the evolution of the FUL-like lineage in basal eudicot is coincident with APG,the difference is that Buxaceae and Proteales are both single lineage and they are paralogous,and then paralogous with Trochodendraceae.TesFUL and TraFUL2 are paralogous genes,and their ancestral gene and TraFUL1 are paralogous genes.It is suggested that a duplication event has happened before the divergence of Trochodendraceae.2.The phylogenetic analyses of B-clade gene subfamily(AP3 gene subfamily and PI gene subfamily):TesAP3-1 and TesAP3-2 are paralogous genes,which suggested that there is a duplication event in the Tetracentron;TesPI1 and TesPI2 are respectively paralogous with TraPI1 and TraPI2,which suggested that a duplication event happened in the common ancestor of Tetracentron and Trochodendron.3.The phylogenetic analyses of A-clade gene subfamily(AG gene subfamily):TesAG and TraAG1 are paralogous genes,and their ancestral gene and TraAG2 are paralogous genes.It is suggested that TraAG1 and TraAG2 is caused by the duplication event before the origin of Trochodendron.Based on the phylogenetic analyses of the A-,B- and C-clade MADS-box gene subfamiles in Tetracentron,it is suggested that Tetracentron and Trochodendron have a close relationship.And, some small scale gene duplication events of the MADS-box gene subfamilies in Tetracentron happened either in the common ancestor of Tetracentron and Trochodendron(PI gene subfamily, FUL-like gene subfamily and AG gene subfamily uncertain) or in Tetracentron(AP3 gene subfamily).Also,the structures and C-motifs of the genes in Tetracentron are similar to Trochodendron.In summary,Tetracentron should be placed in Trochodendraceae.The function of the genes in Tetracentron,comparing to Trochodendron,should be studied in future.