Identification Of Important Genes In Soybean Nodulation And Nitrogen Fixation By Comparative Genomics

Soybean is rich in protein and lipids,and has important nutritional and economic value.Nitrogen is an essential nutrient for soybean growth and development.However,at present,the cost of nitrogen fertilizers is high and there is a potential risk to the environment.Biological nitrogen fixation does not cause environmental pollution and it has high utilization rate,which will benefit the sustainable development of modern agriculture.Therefore,it is of great significance to improve the capacity of biological nitrogen fixation to increase soybean yield.In order to improve the nodulation and nitrogen fixation capacity of soybeans,it is important to identify all key genes that play an important role in nodulation and nitrogen fixation.It is of great economic value to provide target genes for better molecular breeding and high-quality soybean varieties.Medicago truncatula and Lotus japonicus are important model organisms for studying nodulation and nitrogen fixation in legumes.Much valuable results have been obtained,including key genes important in nodulation and nitrogen fixation.In this paper,I first curated all genes that are known to play important role in nodulation and nitrogen fixation in soybean,medicago,and lotus.I successfully annotated 91,91,and 100 important genes involved in the process of nodulation and nitrogen fixation in medicago,soybean,and lotus,respectively.We then identified orthologs groups among these three species using OrthoMCL,which resulted in the identification of 21740 ortholog groups.Among these ortholog groups,149 groups of ortholog contained at least one annotated nodulation or nitrogen fixation gene.By homology analysis,773 candidate genes that may participate in nodulation process were obtained in soybean.This paper proposes soybean “Complete nodulation and nitrogen fixation genome” with a total of 854 genes.These candidate genes have very good homology,and there are gene amplification phenomena in soybean,medicago and lotus.Most candidate genes have GO enrichment.There was response to stimulation,metabolism,transport,biosynthesis,defense response,and protein phosphorylation in biological process.Membrane components,trans-Golgi network transport vesicle membranes,clathrin-coated vesicle membrane,vesicles,extracellular matrix,and other membrane-associated components are included in cellular components.In molecular function,it is related to activities such as calmodulin kinase,ion channel,biosynthesis,transmembrane transport and binding.There was 13 metabolic pathways including flavonoid synthesis pathways,nitrogen metabolism pathways,and plant-pathogen interaction pathways enriched in KEGG analysis.Plant-pathogen interaction pathways contain the most genes.Analysis of the expression of the three sets of data,all of them have differentially expressed candidate genes.Differential expression analysis of the transcriptome of Glycine William 82 was performed,and 23 differentially expressed candidate genes were obtained.Differential expression analysis of transcriptome data of inoculated Rhizobium was performed to obtain 18 differentially expressed candidate genes;Differential expression analysis yielded candidate genes that were differentially expressed from 5 different developmental stages.These differentially expressed candidate genes are likely to play an important role in the process of nodulation and nitrogen fixation which are important for the study of soybean nodulation and nitrogen fixation and provide candidate target genes for molecular breeding.