Study On The Inhibiting Of Volatiles Produced By Streptomyces Alboflavus TD-1 On Botrytis Cinerea

A Streptomyces alboflavus TD-1 was isolated in the soil nearby feed mill, which has a good antagonistic ability against various fungi. The secondary metabolism of S.alboflavus TD-1 plays a great role in inhibitory effect, especially for Botrytis cinerea. Further study shows that its secondary metabolism includes volatiles and non-volatile ones. The results are as followings:(1) Statistical methods, such as single factor and orthogonal design, were employed synthetically to optimize the fermentation conditions of S. alboflavus TD-1 wheat bran medium to produce VOCs, hoping to achieve strongest inhibition effect on the growth of B. cinerea. The optimum fermentation condition:ratio of material to water 1:1, fermentation time 8d, solid bottling capacity8%, inoculation amount 20%,The inhibitory of VOCs produced by S. alboflavus TD-1 increased 1.81 times in the optimized experimental conditions.(2) Antibacterial mechanism of volatile substances produced by S.alboflavus TD-1 in vitro was studied. The results showed that VOCs can inhibit sporulation, mycelia growth and spore germination of B.cinerea and make the hyphae morphological abnormalities, rough surface, and destroy bacteria cell and mitochondrial membrane integrity, make protein, nucleic acid, sugar and protein substances leaked out the cell.(3) The preparation conditions of S.alboflavus TD-1 agent was studied, the results show that oven drying, amount of emulsifier to span 60:polysorbate 80 (1:1) and under the condition of 4℃ to save, the bacteriostatic activity is the highest. In addition, the physical experiments showed that the VOCs also can reduce the viability and infection tomato of B. cinerea to a certain extent.(4) The type and change rule of VOCs produced by S. alboflavus TD-1 of different incubation time was studied by GC/MS. Results showed that in a different culture time, the VOCs are almost the same, but the relative content change is bigger, the main species have aldehyde, terpenoids, phenols, olefin, alkane and aromatic hydrocarbon compounds. The VOCs from bran medium has a large of production from 4 d and reached the highest antifungal activity at 8 d. A total of 63 kinds of compounds were identified based on GC/MS, of which 2-MIB and 1,4-Dimethyladamantane have a bigger relative content, but its bacteriostatic activity still need further verification.