Evaluation Of Growth Promotion Performance Of Endophytic Bacteria Of Codonopsis Pilosula And Molecular Mechanism Of Cadmium Ion Tolerance In CPES11 Strain

Codonopsis pilosula is one of the traditional Chinese medicinal materials.In view of its good medicinal value,it has been used in the treatment of diabetes and some anti-tumor treatments.Serratia fonticola is a kind of bacteria that are widely promoted in the roots of plants.In recent years,the excessive use of pesticides has caused a series of damage to the soil.Environmentally-promoting bacteria have attracted people’s attention.Plant-promoting bacteria can improve the resistance of medicinal plants to heavy metals.Therefore,it is also important to understand the relationship between plant-promoting bacteria and medicinal plants.The content and results of this study are as follows:（1）Codonopsis ginseng was collected from Ming xian,Gansu,and five endophytic bacteria were isolated from the roots and named CPSE11,CPSE12,CPSE22,CPSE32,and CPSE8.The molecular biology was identified and the isolated endophytic bacteria were isolated.Its IAA,iron carrier,phosphorus dissolving,nitrogen fixation,celulase,HCN and other growth-promoting capabilities and heavy metal resistance were tested.As a result,CPSE8 showed excelent IAA-producing ability,with a yield of 146.67mg/L,and CPSE32produced ACC deaminase.It has the highest capacity,with a yield of 1.979μmα·butyronic acid mg/h.（2）Germination test of Codonopsis sibiricum seeds at different cadmium ion concentrations.The test found that after the Cd²⁺concentration was 20mg/L,the germination rate and germination index of cadmium ions were significantly inhibited.The interaction between Codonopsis radiata seedlings and five strains of bacteria The test showed that all four strains could promote the growth of Codonopsis pilosula seedlings in heavy metal environment.Among them,CPSE11 had the best promotion effect.Although CPSE11 had a poor promotion effect on root growth,the above-ground part of Codonopsis.The fresh weight growth and the underground fresh weight growth were 1.42 times and 3.84 times,respectively,and the processed Codonopsis.Seedlings contained the least amount of heavy metals in the body,so CPSE11 was selected for subsequent experiments.CPSE11 extracellular polymer（EPS）was extracted and it was found that EPS had a good effect on promoting germination of Codonopsis sibiricum seeds.Later Codonopsis.Seedlings were tested with CPSE11 and its extracel ular polymer respectively.The hydroponic test had a Cd²⁺concentration of 0,The test was performed under four gradients of 5,10,and 15 mg/L.The experimental results show that CPSE11 has a good performance in promoting the growth of plants.The antioxidant enzymes（SOD and POD）and malondialdehyde（MDA）of the plants were added to CPSE11 and EPS.Are lower than the control.（3）Adsorption experiments with cadmium ions were performed on the extracted CPSE11and CPSE11 cells with different treatments,and different pH,temperature,dosage and initial heavy metal concentration of Cd²⁺were set.The experiments show that the pH has an alkaline environment.Better adsorption effect.The three materials have completely different effects at a temperature of 40℃.At 40℃,the adsorption of Cd²⁺by bacteria is significantly reduced while the adsorption rate of EPS is greatly improved.The thermodynamic and kinetic adsorption experiments found that the adsorption of EPS on Cd²⁺complies with the kinetics second-order model,while the adsorption of EPS-retaining bacteria bodies is more consistent with the kinetics first-order model.All three materials conform to the Langumir equation.（4）Whole genome sequencing of CPSE11.The sequencing results showed that its genome size was about 5,611,152bp,GC content was 53.81%,and it contained 5099 coding genes.We found butyrate metabolism,taurine metabolism,glutathione Metabolism and metabolic pathways of various amino acids,which indicates that the bacteria have a good ability to cope with external environmental stresses.At the same time,we have found the synthesis of a variety of active ingredients,including anthocyanin synthesis,isoquinoline,alkaloids,plant hormones Substances,all of which promote plant growth,the genome-wide information of CPSE11 has been submitted to the NCBI.