[Objective] This study aimed to explore the molecular mechanism of mulberry pigment metabolism regulation. [Method] Chalconesynthase（CHS） gene was cloned from Morus（Moraceae） in silico. The amino acid sequence, physical and chemical properties, transmembrane structural domain, hydrophobicity/hydrophilicity,subcellular localization, secondary and tertiary structure of protein were predicted and analyzed by bioinformatics tools. [Result] The cDNA sequence of CHS gene was 1 365bp by splicing using the software DNAstar and it contained a complete ORF including 1 170 bp which encoded 389 amino acids. Bioinformatic analysis showed that CHS gene included specific peptide sequence RLMMYQQGCFAGGTVLR of chalcone synthase superfamily, but has no signal peptide, belonging to the non-secretory proteins, located inside of cytoplasm. Its molecular evolution is more conservative.[Conclusion] The results above provided foundation for the further studies of structure and function of CHS protein.
[Objective] This study aimed to investigate the functions and related mechanisms of xyloglucan Endotransglycosylase/hydrolases （XTHs） during the growth and development of dahlia. [Method] Using /3-actin as the reference gene, the rela- tive transcription levels of DpXTH1 and DpXTH2 genes in roots, stems, leaves and petals of dahlia were analyzed by real-time RT-PCR. [Result] The DpXTH1 and DpXTH2 were not expressed in the roots, but expressed abundantly in the petals of dahlia. There were little expressions in the stems and leaves of dahlia. [Conclusion] The DpXTH1 and DpXTH2 were petal-specific genes and closely related to the growth and development of petals in dahlia.
[Objective] This study aimed to explore the molecular mechanism of senescence in ethylene-insensitive flowers. [Method] The dahlia petals were used as matedal, and the senescence-associated proteins were isolated and identified using two-dimensional electrophoresis, mass spectrometry and an encoding gene was cloned using molecular biology techniques. [Result] In the two-dimensional elec- trophorogram of proteins from dahlia petals at building color, full flowering and flow- er senescence pedods, a total of 44 protein spots with differences in expression level more than two times were detected. From the 44 protein spots, xyloglucan （XTHs）, a senescence-associated protein, was iso- lated and identified and its expression level was increased continuously with the senescence process of dahlia petals. By using the total RNA of dahlia petals as matedal and a pair of degenerate pdmers, the cDNA sequence of XTH gene was cloned by RT-PCR. The encoding region of XTH gene has a full length of 882 bp, encoding 293 amino acid residues, and is named as DpXTH1 （Accession number： HM053613.1）. The cluster analysis showed that the amino acid sequence of DpXTH1 has high homology with those of XTHs in other plants. [Conclusion] The isolated and identified DpXTH1 from dahlia petals belonged to the XTH family in plants, and its biological function was associated with the senescence process and regulation of dahlia petals.
