Physic-chemical Characteristics, Safety And Antifungal Activity Of Fermentation Liquid Of Chaetomium Aureum Strain HTC

Chaetomium spp. is a very important class of resource fungus with outstanding advantages in control of plant diseases. Chaetomium aureum strain HTC isolated from health walnut leaves is a strain of dominant endophytic fungus with broad-spectrum antagonistic activities and resistance. The red metabolites produced by HTC has good antagonism against many pathogenic fungi. Therefore, C. aureum strain HTC is a potential strain for biocontrol of plant diseases. In order to use C. aureum strain HTC in production of agriculture, the physic-chemical characteristics and safety evaluation of fermentation liquid produced by C. aureum HTC as well as the antifungal activity in vitro, and the control efficacy of different plant fungus were preliminarily investigated in this study.The major results are as follows:1. The confrontation experiment showed that Chaetomium aureum HTC significantly inhibited mycelial growth of 10 kinds of phytopathpgenic fungi. Among these results, the inhibition percentage of mycelial growth of Valsa sordida strain CYP reached to 90.76%. The suppression percentage of mycelial growth of Phytophthora infestans also reached 59.91%. Hyphae coiling of Botrytis cinerea by hypae of C. aureum HTC was observed. The fermentation liquid does not affect the spore germination of Botrytis cinerea, but will slow down the growth time of spore germ tubes.2. The antifungal activities of fermentation liquid produced by Chaetomium aureum HTC was not changed after treatment with the fermentation liquid under 100℃, but after treatment with the fermentation liquid under 121℃, the antifungal activities decreased slightly. This experiment indicates that the fermentation liquid had good stability within 100 ℃. The antifungal activities of the fermentation liquid was lost with the fermentation liquid under pH 2, but when the fermentation liquid was treated with pH 12, its antifungal activities was only decreased slightly. This results showed that the fermentation liquid was stable in the condition of alkali but not stable in acidity condition. Meanwhile, the fermentation liquid was stable in the condition of UV within 60 min.3. The experiment of the security evaluation of fermentation liquid showed that the fermentation liquid had no effect on seed germination rate of wheat, corn and cucumber, but it can able to inhibit seed radicle number, length and weight growth at high concentrations. This results illustrated that the fermentation liquid is safe to use on germination and growth of seed in the appropriate concentration.4. The antagonism test in indoor and greenhouse showed that the strains HTC should suppressed mycelial growth of Botrytis cinerea, but the effect on pepper was relatively better than cucumber in vivo.5. The inoculation experiments of poplar, apple and chestnut shoots by artificial in indoor showed that the fermentation liquid had antagonistic effect on Valsa sordida,V. mali and Cryphonectria parasitica. The suppression percentage of CYP reached 73.68%, indicating that the fermentation liquid significantly suppressed growth and expanding of CYP in vivo. The control efficacy in vivo was consistent with the results of confrontation experiment.