Bjerkandera adusta M1 inhibits Fusarium oxysporum and prevents the wilt incidence in Brassica napus

Abstract

Background: Bjerkandera adusta degrades polycyclic aromatic compounds, such as cellulose and lignin, with the production of laccase and peroxidase. However, its effect on plant disease is unknown. Results: In this study, both the confrontation culture and greenhouse pot experiments were carried out to address the biocontrol mechanisms of B. adusta M1, which was isolated from a unique purple soil (Eutric Regosol), on the growth of pathogenic Fusarium oxysporum f. sp. conglutinans (FOC) and incidence of fusarium wilt in Brassica napus. Results showed that the hyphal growth rate of B. adusta M1 was significantly greater than that of FOC, indicating a strong competitiveness by B. adusta M1. In addition, the B. adusta M1 fermentation broth significantly inhibited the growth of FOC hyphae by 62.79±1.80%, which was greater than an inhibition rate of 40.63±1.68% by the chemical fungicide carbendazim. The image from a scanning electron microscope showed the hyphae of FOC directly was penetrated by the B. adusta M1 hyphae, indicating a strong mycoparasitism by B. adusta M1. Besides, both the B. adusta M1 and B. adusta M1 fermentation broth reduced the incidence and disease index of the fusarium wilt in Brassica napus leaves, and the control effects of different treatments against fusarium wilt were 57.09% and 47.67%, respectively, which were comparable better to 46.11% of the chemical fungicide carbendazim. Furthermore, both the B. adusta M1 and B. adusta M1 fermentation broth increased the activity of superoxide dismutase, catalase, peroxidase and phenylalanine ammonia-lyase, which related to an enhancement of disease resistance. Similarly, both the B. adusta M1 and B. adusta M1 fermentation broth decreased the cell membrane permeability and malondialdehyde contents, thereby reducing the cell membrane damage from the pathogenic fungus. Conclusion: In summary, results from this present study demonstrated that both the Bjerkandera adusta M1 and B. adusta M1 fermentation broth inhibited the growth of FOC and decreased the incidence and disease index of the fusarium wilt disease in Brassica napus. Therefore, B. adusta M1 could be applied as a potential biocontrol fungus to against the fusarium wilt disease.