| Root-knot nematode is one of the important diseases in tomato production,which seriously harms the yield and quality of tomato.As a biocontrol fungus,Paecilomyces lilacin can infect a variety of plant nematodes and promote plant growth.However,in practical applications,there is a problem that the live fungus is easily inactivated at high temperature,difficult to colonize in the soil,unstable in control effect,and harmful to live human spores.Studies have shown that the metabolites of Paecilomyces lilacinus also have certain killing and promoting effects on plants,and they have the advantages of simple application,mass production,no spore diffusion damage,and great research and development potential.However,the different strains and different culture conditions of the metabolites of Paecilomyces lilacinus had significant differences in the killing effect of Meloidogyne incognita.It was found that the organic matter with killing effect was paired with the culture medium to culture the Paecilomyces lilacinus,and the killing effect of the metabolites was better than that of the traditional medium.In view of the above situation,this experiment selected 16 liquid media and analyzed the metabolites of Paecilomyces lilacinus,and selected a liquid medium that is highly virulence to Meloidogyne incognita and has a promoting effect on tomato.The combination provides a theoretical and practical basis for further research on the metabolites of Paecilomyces lilacinus to control tomato root-knot nematodes.In this experiment,the killing effect and composition of 16 metabolites were analyzed.It was found that the killing effect of metabolites was different under different culture conditions,and the types of treatment components were different.The four treatments of adding Jerusalem artichoke straw extract to the culture medium contained more aromatic hydrocarbons,and the best killing effect was ?-3??-3??-2??-1(P1?P2?P3?P4).Four treatment culture conditions were selected as the culture conditions for the subsequent experiments.From the above results?the selected metabolites under the four culture conditions were analyzed,and the results obtained by the test were as follows:(1)The P1 treatment detected three kinds of biomass-promoting substances(content 19.73%)and two kinds of killing substances(11.65%).P2 treatment included 3 kinds of biomass(12.44%)and 3 kinds of killing substances(12.42%).P3 treatment found 3 kinds of biomass(22.65%)and 6 kinds of killing substances(47.17%).The P4 treatment contained 2 kinds of biomass(9.52%)and 2 kinds of killing substances(11.09%).The virulence in the medium has a strong correlation with the virulence in the metabolites.(2)The metabolites of Paecilomyces lilacinus under four culture conditions can significantly reduce the occurrence of root-knot nematode disease,reduce the disease index,root number and soil insect population.P3 treatment significantly inhibited root knot nematode disease compared with other treatments,followed by P2,P1?and P4 treatments.(3)The metabolites of Paecilomyces lilacinus had different effects on tomato growth under the four culture conditions.P3 treatment had the best effect on tomato growth,followed by PI and P2 treatments,and P4 treatment had the weakest growth promotion effect.(4)Under the four culture conditions,the metabolites of Paecilomyces lilacin had different effects on soil nutrient.The specific performance was as follows:the content of alkali nitrogen and organic phosphorus in P2 treated soil was higher than that in other treatments,and the available potassium content in P4 treated soil.highest. |
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