The Induced Resistance Against Phytophthora Capsici By Filtrated Supernatant Fluid Of The Culture Of Entophytic Bacterium TB2

The entophytic bacterium strain TB2 (Bacillus amyloliquefaciens) was isolated from tobacco. The supernatant fluid was filtrated from its culture. And this fluid was used to test the induced resistance on capsicum against Phytophthora capsici. The results indicated that the fluid had a strong induced resistance against the pathogen. During the seedling hood of capsicum, the induced resistance was raised with the induce time extended. When the time was 8d, the induced resistance was fine and steady. In the 12d after inoculating the pathogen, the induced effect reaches 67.89%. As for the capsicum fruit, the effect of resistance was the best when the induced time was 2d, and the induced resistant effect reached 63.67% in 8d after inoculating the pathogen.The biochemistry targets in capsicum fruit and seedling were determined during induce resistance test. The results showed that as for the capsicum fruit, the filtrated supernatant fluid of TB2 culture could induce some enzyme change. In the treatment, inducing for 2d, then inoculating P. capsici, the content of soluble protein was decreased during the inducement, and in the time of inoculating the pathogen the content was lower by 9.23% than that of the water control. The content of malondialdehyde (MDA) was lower by 20.68% or 33.15% than that of the water control in 5d or 7d after inoculating the pathogen. And, in the same treatment the peak of peroxidase (POD) activity appeared between the inoculating times of filtrated supernatant fluid and the pathogen. The peak of β -1,3-glucanase activity of this treatment appeared 1d earlier than that of inoculating filtrated supernatant fluid and pathogen at the same time. The exo-chitinase activity peak appeared in the first day after inoculating the pathogen and the peak value was higher by 164.6% than that of the water control. As for the treatment of inoculating the pathogen only, the content of MDA was raising and arrived 150.8% higher than that of water control. When the capsicum fruit was inoculated with filtrated supernatant fluid, POD activity was 22.73% higher than that of water control. From the above results we can see that the inducement by filtrated supernatant fluid could induce resistance in capsicum fruits and reduce the destruction by P. capsici.