Identification of a biocontrol strain of oat root rot and its control effect

Fusarium avenaceum is one of the main pathogens causing root rot in oats (Avena sativa). In order to develop a green biological inoculant for effective prevention and control of oat root rot, we isolated from healthy oatmeal rhizosphere soil F. avenaceum, an efficient oat antagonist bacteria YF, carried out morphological and molecular identification of the antibacterial spectrum of this bacterium, and investigated through an indoor control test the mechanism of this bacterium against F. avenaceum. The strain was identified as Paenibacillus polymyxa. The activity test showed that the strain had an inhibition rate of 70.69% against the mycelial growth of F. avenaceum and 85.92% against spore germination. Through bacteriostatic spectrum screening, it was found that this strain is effective in controlling eight common pathogenic fungi. The mycelia of F. avenaceum treated with the fermentation broth showed abnormal branching, vesicular deformities, and rupture of the cell wall. In the potted experiment, the control effect of this strain on oat root rot reached 81.45%, which was significantly higher than that of carbendazim (61.87%) (P < 0.05). In addition, this strain showed a better growth promoting effect on oat plant. Therefore, this strain of P. polymyxa has potential as a biological control agent against oat root rot.