Identification And Functional Investigation On AM Fungi Induced Peptides

The arbuscular mycorrhizal(AM)fungus can form a symbiotic relationship with most land plants.The symbiotic mycelium helps plants to better absorb mineral elements and nutrients in the soil and promote plant growth and development.The establishment of a symbiotic relationship can also enhance plant resistance to stress,which is of great significance to improve agricultural production.Earlier studies showed that the polypeptide signaling molecules in plants has an important regulatory role on plant growth and development.Current research on biologically active peptides is still unknown.With the progress of biotechnology,it provides a broad application prospect for the functional analysis,application and development of bioactive peptides.In this experiment,peptides were extracted from corn roots at different time points after symbiosis between corn and AM fungi.The peptides with significant differences were isolated as the research object.After peptide treatments,changes of the AM fungi infection efficiency and marker gene expression related to symbiosis were analyzed.Transcriptome was used to analyze changes of downstream symbiosis-related signaling pathways involved in AM fungal symbiosis.These results are shown as follows:1)In the plate experiment,the number of spores in the MSR medium added with the polypeptide dilution solution were significantly increased in comparison with the control group.The concentration increase of polypeptide dilution solution improved the number of spores.2)The plants treated with peptides showed no obvious difference in the phenotype after symbiosis.No obvious effect was exhibited on the root length and height of corn.3)After treatment with peptide diluent,the infection rate of AM fungi was reduced.The branches and vesicle structures were basically not found.4)The experimental groups treated with the peptide diluent were selected and the untreated group was used as the control group.Upregulation and downregulation of large amounts of gene expression.5)GO enrichment analysis was carried out on differential genes.In biological processes,differential genes mainly focus on catabolism,response to stimuli,and biosynthesis.In terms of molecular function,differential genes mainly enrich in binding,transferase activity,and reduction.In terms of enzyme activity and cellular components,the differential genes are mainly enriched in the cellular components such as the mitotic spindle central region and nucleolus.6)KEGG metabolic pathway analysis was also performed on the differential genes.Between the experimental group and the control group,the differential genes are mainly involved in biological processes such as phenylpropane metabolic pathway,plant hormone signal transduction and flavonoid biosynthesis.By contrast,the differential genes are mainly involved in biological processes such as phenylpropane biosynthesis,plant MAPK signaling pathways,plant hormone signal transduction,plant pathogen interactions,and protein processing in the endoplasmic reticulum.The peptide used in this study may affect lignin synthesis through the phenylpropane biosynthesis,which in turn affects the corn-AM fungal symbiosis efficiency.