Effect Of Paraphoma Chrysanthemicola On The Growth And Active Component Accumulation Of Codonopsis Pilosula(Franch.) Nannf.mediated By Salicylic Acid

As one of the main authentic medicinal materials in Gansu Province,Codonopsis pilosula（Franch.）Nannf.is an important pillar of the Chinese medicine industry in Gansu Province.Codonopsis polysaccharides（CPPs）is one of its main components,and lobetyolin was used as a characteristic component in the 2015 edition of the Pharmacopoeia of the people’s Republic of China（2015 Edition）to identify C.pilosula.A large number of studies have shown that fungal elicitors play an important role in plant growth and metabolism,disease resistance and the synthesis of active metabolites.The fungal elicitor can be used as an effective biological bacterial fertilizer for green cultivation of traditional Chinese medicine.In the previous study,the research team found that salicylic acid（SA）plays an important regulatory role in the anabolic metabolism of CPPs and lobetyolin.At the same time,an endophytic fungus Paraphoma chrysanthemicola strain DS-84 with a significant effect on the growth of the plant of C.pilosula and the accumulation of metabolites was obtained.However,its underlying mechanism is still unknown.However,its underlying mechanism is still unknown.Accordingly,this study mainly explored the effect of salicylic acid-mediated P.chrysanthemicola strain DS-84 on the growth of C.pilosula and the accumulation of active ingredients.The main findings are as follows:（1）The endophytic fungus strain DS-84 was screened from the roots of C.pilosulae using tissue surface disinfection,pure culture and other techniques,and identified as P.chrysanthemicola strain DS-84 by morphological,physiological,biochemical,and molecular biological methods.Its fatty acid composition conforms to the basic composition characteristics of phospholipid fatty acid of Dark septate endophyte（DSE）fungus and P.chrysanthemicola.The best carbon source,nitrogen source and phosphorus source of this strain are mainly sucrose,peptone and calcium phosphate,while lecithin is the best phosphorus source in liquid culture.It can secrete amylase,cellulase,chitosanase,lipase,alkaline protease and complex enzyme.When cultured in liquid PDA medium containing 0.5 mg/m L tryptophan for 5 days,the IAA content reached 28.27 mg/L.When the concentration of the fungus preparation was 10⁵cfu/m L,the highest germination rate of C.pilosula seeds was 46.0%.（2）The entire genome of P.chrysanthemichola strain DS-84 was sequenced using SMRT sequencing technology,and the genome was annotated with the help of various databases.The results showed that the genome size of strain DS-84 was about 46.30Mb,and the content of G+C was 50.30%.A total of 16,040 protein-coding genes are predicted,of which 10.03%（1609）are secreted proteins,and 1862 proteins have transmembrane regions.In the DS-8 genome,2362 carbohydrate active enzyme-encoding genes and 37 secondary metabolic gene clusters were predicted.（3）P.chrysanthemichola strain DS-84 is not pathogenic to the seedlings of C.pilosula,and can infect the roots of C.pilosula seedlings to form dark septate hyphae and micro sclerotia,thus forming a stable hypha root relationship.（4）P.chrysanthemichola strain DS-84 treatment group significantly increased the fresh weight,root weight and leaf quantity,and the salicylic acid treatment group significantly increased the root diameter.P.chrysanthemichola strain DS-84 and SA can promote the accumulation of codonopsis polysaccharides and lobetyolin in the root of C.pilosula to varying degrees.P.chrysanthemichola strain DS-84 infects the roots of C.pilosula seedlings and exogenously adds salicylic acid to the interaction system,which stimulates the changes in the content of the plant’s signal molecules and triggers changes in antioxidant enzymes,sugar metabolism related enzymes and other components in the plant.The fungal treatment group mainly showed a decrease in the hydrogen peroxide content in the roots of the seedlings,an increase in the hydrogen peroxide content in the leaves,an increase in the activity of peroxidase in the stem,an increase in the activity of the acid invertase in the cell wall of the leaves,and an increase in the content of CPPs and alkynosides in the roots.The salicylic acid treatment group caused an increase in the content of hydrogen peroxide in the stem,an increase in APX activity in the leaf,an increase in the activity of sucrose phosphate synthase in the plant,and an increase in the content of CPPs and alkynosides in the root and stem.Under the combined treatment of fungi and salicylic acid,the content of hydrogen peroxide in leaves and codonopsis glycosides in roots increased more than that of fungi and salicylic acid alone.（5）The activities of sucrose synthetase,sucrose phosphate synthetase,cytoplasmic invertase and cell wall invertase were positively correlated with the content of hydrogen peroxide in stem and leaf.It is speculated that P.chrysanthemichola strain DS-84 and SA can promote the activities of sucrose synthetase,sucrose phosphate synthetase and invertase by increasing the content of H₂O₂,so as to promote the carbon metabolism of plants,cause the excess of non structural carbohydrates,and promote the accumulation of polysaccharides and polyacetylenes.