Molecular Mechanism Of Soybean GmRGS1 Regulating Root Nodule Development And Its Application

Soybean originated in China and is now cultivated all over the world.It is an important oilseed and grain crop,but Soybean production in China is highly dependent on its imports,and the current self-sufficiency rate is less than 30%.China is the largest soybean consumer and importer in the world.There is a huge contrast between low soybean output and high demand,and the demand side is prominent,resulting in high soybean importion and import dependence.How to improve soybean production is a crucial problem that needs to be solved urgently.Soybean is a typical biological nitrogen-fixing crop.Rhizobium can not only promote the absorption of legumes themselves and other nutrients,but also increase the yield of legumes.Biological nitrogen-fixing legumes can provide nitrogen nutrition for plants and enable plants to obtain more more biomass and yield.Sugar not only provides carbon source and energy for plant growth and development,but also regulates many biological processes throughout the plant life cycle,from embryogenesis to senescence.As an important product of photosynthesis,sugar synthesis,transportation,metabolism and storage must be adapted to plants living environment and growth and development.However,the current regulatory network mechanism of sugar signal transduction in root nodulation is still unclear.In this study,molecular biology techniques were used to study the regulation of sugar signal-related genes in the process of soybean nodulation,which laid a foundation for the analysis of soybean sugar signal transduction pathways and the screening of high-efficiency nitrogen-fixing soybeans.This paper takes soybean as the research object,and studies the regulation of glucose on soybean nodulation process through a series of physiological and biochemical experiments and in vitro experiments.The main researches are as follows:The homologous gene of At RGS1 in soybean was analyzed with bioinformatics tools.Through the identification and phylogenetic analysis of GmRGS1 family genes,two homologous genes of At RGS1 were identified in the soybean genome.Based on their close relationship to At RGS1,they were named GmRGS1 a and GmRGS1 b.In addition,by analyzing the expression data on the Soy Base website,it was found that GmRGS1 a was specifically expressed in leaves,flowers and roots,and GmRGS1 b was specifically expressed in roots and flowers.Preliminary studies on the biological function of GmRGS1 a found that the overexpression of GmRGS1 a promoted soybean nodulation and increased the number of nodules,while the loss of function of GmRGS1 a caused by CRISPR/Cas9 gene editing technology could inhibit the number of soybean nodules,indicating that GmRGS1 a is a soybean nodule.positive regulator.Further analysis of early nodulation gene responses by q RT-PCR showed that GmRGS1 a acts downstream of these genes to directly or indirectly regulate their transcription levels,thereby participating in the signal transduction regulation of nodulation signaling pathway and nodulation self-regulatory signaling pathway.Molecular marker screening was carried out using germplasm resources preserved in the laboratory.After analysis,it was found that the GmRGS1 a locus was polymorphic in soybean landrace,cultivar and wild varieties.It is proved that the marker is correlated with soybean nodulation,which also provides a certain method and theoretical basis for the screening of soybean germplasm resources.