STUDY ON THE GROWTH-PROMOTING POTENTIAL AND DISEASE RESISTANCE OF THE ANTAGONISTIC BACTERIUM FRANKIA FRANCESE F1 ON GINSENG ROOT ROT AND RUST ROT

To effectively control root rot and rust rot, two major destructive diseases in ginseng production, an antagonist strain F1 was selected for molecular biology identification and showed 100% homology with Frankia casuarinae strain Ccl3 of the genus Mucor. The germination test found that the antagonist F1 could fix nitrogen, and secrete 3-indoleacetic acid (IAA) and iron carriers. And the seed germination test found that the germination rate of ginseng seeds diluted 50 times with F1 fermentation solution was 100%. Compared with the blank treatment, the increase in embryo length was 283.33%. The treatment of ginseng seedlings with different concentrations of fermentation solution improved the resistance of ginseng seedlings to root rot and rust rot. Among them, diluting 50 times, F1 fermentation solution significantly increased the height, root length, fresh weight, dry weight, root vigour and chlorophyll content of ginseng plants. It reduced the malondialdehyde content of leaves, significantly affecting ginseng seedlings' growth. At the same time, diluting 50 times, the F1 fermentation solution significantly increased the expression of biological control genes in plant leaves. It reduced the incidence and disease index of ginseng root rot and rust rot. The biological control effect of the F1 fermentation solution on ginseng reached 78.72%.