Systematic Identification And Analysis Of Fusion And Fission Genes In Rhizobia

Gene fusion and fission events are key mechanisms in the evolution of gene architecture,they are very important for studying gene evolution and predicting protein interactions.This process occurs on the coding sequence,which has a visible effect on the protein structure,resulting in the damage of gene function.Because gene fusion has a variety of uses,such as specific diagnostic markers,predictive indicators,and as more and more genome is fully sequenced,the detected gene fusion is gradually increasing.Gene fusion analysis has been used to identify protein functional links in prokaryotes as well as in eukaryotic model organisms,such as yeast and Drosophila.Although a large number of rhizobial genome has been sequenced,there is still a huge gap in the analysis of the frequency and regularity of gene fusion and fission in rhizobia.In this study,the gene fusions and fissions in 111 rhizobial genomes were analyzed.In this study,totally 77,689 composite genes were detected.The frequency of gene fusions were significantly larger than gene fissions suggesting that the increasing diversity and complex of rhizobial proteomes.The composite genes were significantly enriched in some functions or pathways.In addition,we predicted their corresponding protein-protein interactions(PPI)based on the gene fusions and fissions.The predicted members of the PPI network were found to be often participated in a same metabolic pathway,so they are functionally related and most of the members of the protein interaction pairs found to be independently evolved,therefore,gene fusion and fission have a very important influence on the evolution of the genomic function of rhizobia.This is the first study of protein functional links in rhizobium identified by gene fusion analysis.Our study may be helpful to promote the understanding of rhizobial symbiotic evolution.Moreover,the predicted interaction proteins can be further confirmed by other experimental methods,so as to improve the information of rhizobia and promote the evolution of Rhizobium.