Secondary Traits Study On Overexpression Of Tabacc O Of PsnSuSy1, PsnSuSy2 And PsnSuSy1 Of Popul Us Simonii × P. Nigra

Sucrose synthase is one of the key enzymes in sucrose metabolism of plants. which plays an important role in the synthesis of starch and cellulose in plants,and the distribution of carbon sources.In order to explore the effects of sucrose synthase gene in secondary growth, SuSyl was cloned from Populus simonii×P. Nigra and to PsnSuSy2 (kept in the laboratory) transgenic lines as male parent, PsnSuSyl transgenic lines as female, PsnSuSy1×PsnSuSy2 were obtained by way of hybridization.This studies preliminary identification of PsnSuSyland the hybrid strains.The main contents and results are as follows: 1.The cloning and bioinformatics analysis of SuSyl.SuSyl was cloned from Populus simonii x P. nigra in length 2495 bp fragment and named PsnSuSyl. Bioinformatics analysis showed that PsnSuSyl encoding 805 amino acids,the molecular weight was 92.57 kDa and isoelectric point PI is 6.07.The secondary structure of the protein is mainly based on a helix. There was no transmembrane region and the signal peptide cleavage site in this protein.Subcellular localization prediction showed PsnSuSyl belonged to cytoplasmic type. 2.PsnSuSyl tissue-specific expression and subcellular localizationThe expression specificity of PnsSuSy1 was analyzed by RT-PCR and fluorescence quantitative PCR technique. psnSuSyl had highest expression in the excessive xylem,followed by Secondly expression in secondary xylem, medium expression in Excessive formation and Secondary formation, and root, petiole,primary leaves, excessive leaves, the secondary leaf, primary xylem,primary cambium expression abundance was relatively low.This paper constructed pGWB5-SuSyl-GFP plant expression vector and transiently expressed onion epidermal cells via gene gun,to study the subcellular localization of PsnSuSyl,The results showed that PsnSuSyl encoding protein was localized in the cytoplasm and nucleus. 3 Functional analysis of PsnSuSyl over expression of tobacco and PsnSuSy1×PsnSuSy2 hy brid tobacco Research on overexpression of PsnSuSyl in Tobacco and PsnSuSy1×PsnSuSy2 hybrid tobacco showed that the plant height,leaf Length,leaf width,biomass and stem strength were significantly higher than the wild type; Secondary plant cell wall thickness was increased significantly in slices of transgenic tobacco and PsnSuSy1×PsnSuSy2 hybrid tobacco stems by using environmental scanning electron microscope.SuSy activity of transgenic tobacco and hybrid tobacco were increased in various degree than the wild type.The chlorophyll content of tobacco and hybrid tobacco were both higher than that of wild type.The content of cellulose and hemicellulose in the stem of transgenic tobacco and hybrid tobacco was significantly higher than that of the wild type,while the lignin was decreased. There was no significant change in these traits between transgenic tobacco and hybrid tobacco.This indicated that overexpression of PsnSuSyl and PsnSuSy1×PsnSuSy2 hybrid could promote the growth of transgenic plants,improve the biomass,and have some effect on plant secondary growth.