Effects Of Protein Powder And Trace Element Complex On Sporulation And Efficacy Of Beauveria Bassiana Strain K

Beauveria bassiana Balsamo is an insect pathogenic fungus,which is widely used in biological control of pests since it has the advantages of strong pathogenicity,environmental friendliness as well as broad insecticidal spectrum.B.bassiana can be used for controlling of agricultural and forestry pests.It is an important biological pesticide for modern pest control and is one of the most studied insect pathogenic fungi.In order to improve the spore production and efficacy of B.bassiana,this study used a new strain of B.bassiana named KN as the test material,combined with microbiological and biological techniques,to explore the effects of different concentrations of protein powder and trace element complexes on the spore production and efficacy of B.bassiana KN.The results showed that the colony of B.bassiana KN was Rong-shaped in the early stage and colorless on the back.Under the microscope,it can be seen that the sporogenous cells of B.bassiana KN are clustered on conidiophores,hyphae and vesicles,and the sporogenous cells are solitary.The shape of conidia is oval,and the spores are smooth and transparent.The spore production and drug efficacy could be improved by adding different concentrations of trace element complexes and protein powder to the culture medium.The sporulation and efficacy of 0.01 % trace element complex medium were significantly higher than 0.05 % trace element complex medium.The sporulation and efficacy of 0.1 % protein powder medium were significantly higher than those of 0.5 % protein powder medium.There was no significant difference in colony size,p H,and viscosity under different culture conditions.The biomass of the culture medium supplemented with0.01% microelement complex and 0.1% protein powder were significantly higher than that of the PDA culture medium.There were significant differences in spore production among different conditions during conidial spore production.B.bassiana from the culture medium with a concentration of 0.01% trace element complex and 0.1% protein powder showed the highest spore production.Furthermore,transcriptome sequencing of KN m RNA was performed using high throughput sequencing technology to obtain gene expression profiles regulated by protein powder and trace element complexes.Results showed that the four comparative groups annotated the catalytic activity,metabolic process,structural molecular activity,cellular process,antioxidant activity transport activity,and other functions after GO annotation of differential genes.The metabolic pathways involved in cell growth and death,signal molecules and interactions,transportation,and catabolism.Transcriptome sequencing analysis showed that the concentration of 0.01%trace element complex had a significant positive effect on the spore production of B.bassiana KN.However,it will increase metabolic pressure and enhance the catalytic activity of enzymes,resulting in a decrease in spore production when the concentration is 0.05%;The concentration of 0.1%protein powder also had a significant positive effect on the spore production of B.bassiana KN whereasit will increase the metabolic pressure and increase the degradation pathway,resulting in a decrease in spore production when the concentration is 0.5%.This study not only clarified the biological morphological characteristics of B.bassiana strain KN,but also measured the effects of different ratios of protein powder and trace element complexes on the spore production and efficacy of the strain KN.Through transcriptome analysis,we found that the spore production of B.bassiana KN is associated with the related pathways of growth and metabolism in protein powder and trace element complexes.These conclusions provide a scientific basis for the efficient and stable spore production of the strain KN,which laid a foundation for further determining the constitution of protein powder and trace element complex for efficient production of strain KN and creating the best conditions for spore production and large-scale production.