Study On The Affect Of 4 Trace Element On Paenibacillus Polymyxa Pp-7250 Proliferation,Activity And Colonization In Ginseng

Ginseng endophyte of Paenibacillus polymyxa is a kind of probiotic bacteria with many biological activities,such as increasing plant resistance,promoting plant growth,anti-oxidation,anti-tumor and so on.It has been designated by the Ministry of Agriculture of our country as the first class strain which can be exempted from safety inspection.Its development and application value is very high.Therefore,it is of great theoretical significance and practical guiding value to explore the best suitable method that can promote Paenibacillus polymyxa proliferation and improve their activity.In this paper,first,the concentration of Paenibacillus polymyxa Pp-7250 and the number of spores were used as evaluation indicators.The effects of 4 kinds of trace elements on the proliferation of Pp-7250 in different growth stages were analyzed,and the best C source and N source were determined,and then 20 kinds of ginsenoside monomer were used as evaluation index.Again,the effect of the mass concentration of 4 kinds of trace elements on the antibacterial activity of the Pp-7250 was determined by the filter paper method.The main results are as follows:1.The effect of the mass concentration of 4 kinds of trace elements on the proliferation and transformation of ginsenoside activity of Pp-7250:The trace elements of Cu²⁺,Fe²⁺,Mn²⁺and Zn²⁺has significantly effect on the proliferation and transformation of ginsenoside activity of the Pp-7250?P<0.05?.The optimum concentration is respectively 30mg/L,50mg/L,50mg/L and100mg/L.2.Optimization of C and N sources of Pp-7250 in large-scale culture:Using wheat starch instead of potato C source can significantly promote the proliferation of Paenibacillus polymyxa,but when potato starch,sweet potato starch,corn starch and flour replace potato C source,the multiplication effect of Pp-7250 is not good?P<0.05?.Using soybean meal instead of potato N source can significantly promote the proliferation of Pp-7250,but when peptone,urea,and yeast powder.replace potato N source,the multiplication effect of Pp-7250 is not good?P<0.05?.The best formula for the large-scale culture of Pp-7250:glucose 20g/L,wheat starch 6g/L,soybean meal 4g/L.3.The effect of 4 kinds of trace elements on the number of live bacteria of Pp-7250 in the storage process at ambient temperature:The optimum concentration of Cu²⁺,Fe²⁺,Mn²⁺and Zn²⁺can significantly improve the live bacteria number of Pp-7250?p<0.05?,and Zn²⁺has the best promotion effect,and increases by 68%compared with the PDB group;The combination of four trace elements is better than single trace element in promoting the proliferation of living bacteria of Pp-7250?P<0.05?.Compared with the PDB group,the increase was more than 73%.The number of live bacteria was still above 10⁷ CFU/mL in the combination of four trace elements and wheat soybean meal group at the 8th week.4.The effect of the mass concentration of 4 kinds of trace elements on the antimicrobial activity of Pp-7250:The optimum concentration of Cu²⁺,Fe²⁺,Mn²⁺and Zn²⁺can significantly improve the antimicrobial activity of Mucor,Fusarium,Geotrichum candidum and Pseudomonas.And Zn²⁺has the best promotion effect,and increases by 54.23%,57.11%,61.79%,50.40%compared with the PDB group;The combination of four trace elements is better than single trace element in promoting the antimicrobial activity of Pp-7250?P<0.05?.Compared with the PDB group,the increase was 55.71%,61.52%,64.30%,60.85%.5.The effect of 4 kinds of trace elements on the field trial result of Pp-7250:Compared with the PDB group,the disease prevention and promotion ability were still significantly promoted in the combination of four trace elements and wheat soybean meal group,and ginsengside of root and leaf were promoted?P<0.05?.The biological control efficiency was 69.92%in the combination of four trace elements and wheat soybean meal group.Compared with the PDB group,the root weight,yield,specific root weight,stem diameter,leaf length and plant height of ginseng increased by44.31%,37.84%,26.52%,31.40%,24.98%,20.12%.Compared with the PDB group,ginseng root saponins of Rg1,Re,Rg2,Rc,Rb2,Rb3,Rd were increased;ginseng leaf saponins of Rg1,Rb1,F1,protopanaxatriol,CK were increased.6.The effect of 4 kinds of trace elements on the colonization result of Pp-7250:Compared with the PDB group,the number of colonization was significantly promoted in the combination of four trace elements and wheat soybean meal group?P<0.05?.The most colonization was6.69×10⁶cfu/g,5.20×10⁶cfu/g,10.7×10⁶cfu/g in the ginseng root,stem leaf and rhizosphere soil.The number of colonization increased by 63.98%?39.81%?29.44%.7.The effects of 4 kinds of trace elements on the rhizosphere bacterial community of ginseng:Seven species of bacteria were identified in rhizosphere soil of ginseng,of which 6 strains were probiotics?Paenibacillus polymyxa,Bacillus amyloliquefaciens,Bacillus mycoides,Bacillus subtilis,Lysinibacillus,Bacillus cereus?,and 1 strain was pathogenic?Chryseobacterium soldanellicola?.The number of probiotics was significant promoted;the number of pathogenic was significant inhibition in the combination of four trace elements and wheat soybean meal group?P<0.05?.