Molecular Evolution And Functional Divergence Of ODD Gene Family Related To GA Synthesis In Populus Trichocarpa

2-oxoglutarate dependent dioxygenase,2-ODD/ODD,is an important class of oxidases involved in various oxidation reactions in animals,plants,and microorganisms.In this study,the woody plant Populus trichocarpa was used as the research material.The function of different ODD gene family members in the synthesis and metabolic pathway of gibberellic acid was explored,and the mechanism of functional differentiation was further explored.By analyzing the gene structure,expression pattern and subcellular localization of ODD gene family members related to gibberellin synthesis in P.trichocarpa,the following main conclusions were obtained:1)A total of 124 ODD genes were identified in P.trichocarpa,of which 27 ODD genes were involved in the biosynthetic pathway of gibberellin.Compared with the model dicotyledonous plant Arabidopsis thaliana,gene expansion was observed in the P.trichocarpa ODD gene family.2)The 27 PtODD genes from P.trichocarpa belonged to 4 subfamilies:C19-GA2ox,C20-GA2ox,GA3ox,and GA20ox,all of which were located on 14 out of 19 chromosomes of P.trichocarpa genome.Among the 27 genes,ten pair PtODD genes each located in apair of paralogous blocks with a tenable collinear relationship,accounting for 74.07%.This can be considered to be the result of the large-scale duplication event.The other 6 genes formed 3 gene clusters,accounting for 22.22%,which may be derived from tandem repeats.Thus,large-scale duplication mainly contributed to the expansion of ODD genes involved in gibberellin anabolism in P.trichocarpa.3)Gene structure analysis revealed that some genes,belonging to different subfamilies or within the same subfamily,had different gene structures.For example,the subfamily C19-GA2ox has three exons and the subfamily C20-GA2ox has two.Some members of the GA3ox subfamily have three exons and others contain only two exons.The differentiation of the gene structure may indicate changes in gene function.4)18 PtODD genes were successfully sub-cloned into the expression vector.After inducing by IPTG,the results showed that PtODD genes can be expressed in Escherichia coli.While the subcellular localization of 18 PtODD proteins did not show significant differentiation.The molecular evolution and the functional differentiation mechanism of 27 ODDs involved in the synthesis and metabolism of gibberellin in P.trichocarpa had been deeply explored.Which showed that their expression patterns had indeed differentiated,while the functional differentiation mechanism has not been exactly resolved.