Mechanism of strain TR-4 against leaf disease of × Dress.

Background: species are among the most common pathogens in agriculture and forestry, and their control is urgently needed.

Methods: In this study, a total of 68 strains of biocontrol bacteria were isolated and identified from × rhizosphere soil.

Results: The isolates were identified as by 16S rRNA. The inhibitory effect of TR-4 on was confirmed by an antagonistic experiment. The inhibitory effect of TR-4 was 98% at a concentration of 10 µl/ml bacterial solution, protection of the plant and inhibition of was evident. Moreover, the secretion of cellulase and chitosan enzymes in the TR-4 fermentation liquid cultured for three days was 9.07 mol/L and 2.15 µl/mol, respectively. Scanning electron microscopy and transmission electron microscopy confirmed that TR-4 destroyed the cell wall of , resulting in leakage of the cell contents, thus weakening the pathogenicity of the bacteria.