Genome-wide Identification And Characterization Of UDP-glucose Dehydrogenase Genes In Moso Bamboo And Functional Analysis Of PeUGDH4

Phyllostachys edulis,a fast-growing “grass”,which is applied widely on plant cell wall research due to its high strength,toughness and ductility.Therefore,the study on the function of cell wallrelated genes of P.edulis will provide some guidance for the improvement of the research on cell wall and the development of bioenergy.Uridine diphosphate glucose dehydrogenase(UGDH)converts UDP-glucose into UDP-glucuronic acid which could form many intermediate metabolites used as important precursors for plant cell wall synthesis by continuous glycosylation.UGDH especially played an essential role in hemicellulose synthesis,which may have an effect on cell wall thickening by increasing the deposition of hemicellulose.In this research,genome-wide identification and characterization of UDP-glucose dehydrogenase genes in moso bamboo were carried out.The main results are as follows:1.Nine members of PeUGDH gene family were screened by genome-wide identification,containing three expected conservative domains.The results of phylogenetic analysis with gene structure and protein conserved motif showed that the PeUGDH gene family could be divided into two categories(C1and C2)and it was inferred that PeUGDH members in the same groupmay play the similar functions.Analysis of gene duplication events and divergences revealed that the Ka/Ks ratio of all gene pairs was less than 1,indicating that PeUGDH genes were mainly affected by purification selection in the process of evolution.An examination of organ-specific PeUGDH expression indicated that more than 77% of the genes were predominantly expressed in the stem.And the content of lignin and hemicellulose in stem was the highest,relevent to the high expression of most PeUGDHs in stems.2.The prokaryotic expression vector pET32a-PeUGDH4 was transformed into E.coli and soluble PeUGDH4 proteins with enzyme activity were produced.PeUGDH4 promoted the accumulation of soluble sugar in transgene E.coli.3.In order to analyze the function of PeUGDH4 gene,transgenic Arabidopsis thaliana and Nicotiana tabacum were obtained by Agrobacterium tumefacien transformation.In detail,the results of transient results showed that PeUGDH4 was mainly located in the cytoplasm.The analysis of cell wall components indicated that PeUGDH4 overexpression significantly increased the content of soluble sugar and hemicellulose in transgenic plants.Moreover,the results of paraffin section demonstrated that the xylem cells of transgenic A.thaliana increased with deeply stained phloem and the structure of cell wall was arranged densely in the stem section,which may contribute to the thickening of the cell wall.4.In summary,the PeUGDH4 gene was critical for synthesizing many nucleotide sugars and helppromote the carbohydrate metabolism related to cell wall synthesis.The results of this study will provide useful genes and new data for the breeding of trees and crops.