Cloning And Expression Of Flowering Genes In Tree Peony

Tree peony(Paeonia L.) is famous ornamental flowers referred to as ‘the king of flowers’ due to their rich palette of horticultural varieties and deep ethnobotanical history. The large, showy, colorful and fragrant flowers are very attractive. Now there are more than 1,000 varieties under cultivation in China. Tree peony is flowering in the beginning of April and the late of April, in the spring. The blossom time(about 15 days) is short and relatively concentrated, compared with other flowers. These characteristics limit the industrialization development of tree peony. Therefore, it is necessary for further analysis of the molecular mechanism of flowering to shorten the juvenile period, accelerate the genetic improvement, and promote the ornamental value.In this work, the flower buds of tree peony cultivar ’Luoyang Hong’ were used as materials to separate flowering genes by RT-PCR. Finally, the full length cDNA clones encoding PsFUL1, PsSOC12, Ps AGL15 were successfully isolated. The expression profiles of three genes in different organs of tree peony were investigated by qRT-PCR. The results are as follows:(1) Few high homology sequences were cloned by building local database and Blast according to the transcriptome data of tree peony cultivar ’Luoyang Hong’. Specific primers were designed after the bioinformatics analysis of the above sequences. Finally, genes Ps FUL1, PsSOC12, PsAGL15 were successfully cloned from the flower buds of tree peony cultivar ’Luoyang Hong’ by RT-PCR.(2) The Open Reading Frame(ORF) of Ps FUL1 was 768 bp, encoding 255 amino acids, that the full length was 1072 bp belonging to AP1/FUL subfamily. There were MADS, K-box, and ARG80 domains of Ps FUL1. Bioinformatics analysis of Ps FUL1 showed that the majority of PsFUL1’s region was hydrophilic region, belonging to hydrophilic protein. Prediction of secondary structure suggested that PsFUL1 included more irregular α helix and irregular coils. Compared with other homologous AP1/FUL amino acid sequences, it was found that the maximum similarity of PsFUL1 from vitis was 69%. The expression profile of Ps FUL1 showed that it was expressed higher in buds, and lower in roots.(3) The Open Reading Frame(ORF) of PsSOC12 was 600 bp, encoding 199 amino acids, that the full length was 957 bp. There were MADS, K-box, and ARG80 domains of Ps SOC12, was as integration factorof flowering pathway. Bioinformatics analysis of Ps SOC12 showed that the majority of PsSOC12’s region was hydrophilic region, belonging to hydrophilic protein. Prediction of secondary structure suggested that PsSOC12 included more irregular α helix and irregular coils. Compared with other homologous SOC1 amino acid sequences, it was found that PsSOC12 had high similarity with eucalyptus, prunus, fragaria, vitis and citrus. The expression profile of PsSOC12 showed that it was expressed higher in buds.(4) The Open Reading Frame(ORF) of PsAGL15 was 741 bp, encoding 246 amino acids, that the full length was 1096 bp belonging to AGL15 subfamily. There were MADS, K-box, and ARG80 domains of PsAGL15. Bioinformatics analysis of PsAGL15 showed that the majority of PsAGL15’s region was hydrophilic region, belonging to hydrophilic protein. Prediction of secondary structure suggested that PsAGL15 included more irregular α helix and irregular coils. Compared with other homologous AGL15 amino acid sequences, it was found that the maximum similarity of Ps AGL15 from nelumbo was 58%. The expression profile of PsAGL15 showed that it was expressed higher in buds, and lower in roots and blades.