Research On The Bionomics Of Chaetomium Aureum HTC And Detection On Its Antibacterial Activity

Chaetomium aureum HTC strain was an endophytic fungus strain with good biocontrol activity, isolated from the leaves of walnut. In this paper, the biological characteristics of this strain and its biocontrol activity were investigated, the studies on its biocontrol mechanism, optimize the cultural conditions, to carry out large-scale inoculum production, biological control of plant diseases and its application in the field could reduce pollution of the ecological environment caused by the large-scale use of chemical pesticides have important theoretical significance. The main results are as follows:1、Study on the biological characteristics of Chaetomium aureum HTC showed that, compared with Czapek medium, maltose medium, the basic medium, Chaetomium aureum HTC grew fastest on PDA medium; Chaetomium aureum HTC was able to grow at10～30℃, better grow at25～30℃. Colonies was the fastest growing at25℃. Chaetomium aureum HTC was able to grow in a broad scope of pH value from3.43to10.05and it grew better in neutral and slightly acidic environment; Lactose, xylose and fructose was able to promote the growth of Chaetomium aureum HTC. The organic carbon source had little effect on the growth of HTC. Inorganic carbon source inhibited its growth. Organic nitrogen was more conducive to the growth of the mycelium. The influence of the types of nitrogen source was not significant. The beef extract could significantly promote growth of HTC. The effect of inorganic nitrogen sources was not obvious or conducive to their mycelial growth.、The result of the fermentation time effect on the antibiotics production of Chaetomium aureum HTC indicated that production of antibiotics content was increased with the prolong of fermentation time and occurred a decreasing trend after11d, produced the most antibiotics at11d.3、The results of resistance to stress of Chaetomium aureum HTC show that Chaetomium aureum HTC has strong resistance to water stress, but its resistance to salt stress ability is not strong. Chaetomium aureum HTC was able to only grow in the salt concentration at lower than0.5mol/LNaC1PDB medium, when the concentration of polyethylene glycol (PEG) in the PDB medium reaches20%, the mycelia growth was significantly inhibited.4、The detection of biocontrol activity of antibiotic substances from Chaetomium aureum HTC was conducted. The results of confrontation culture show that Chaetomium aureum HTC was able to inhibit test pathogenic fungi with different degrees of inhibition. One of the best at inhibition is Botrytis cinerea, followed by Fusarium oxysporum and Colletotrichum coccodes. The results of inhibition against pathogenic fungi by Chaetomium aureum HTC crude extract solution show that crude extracts had some inhibitory effect on a variety of pathogenic fungi, to further expand the antibiotic spectrum.5、Studies on the tolerance to fungicides against Chaetomium aureum HTC show that, the order of inhibitory effect was thiophanate-methy1> mancozeb> metiram> dimethomorph> kresoxim> chlorothalonil. Inhibitory effect of dimethomorph, kresoxim and chlorothalonil on the strain HTC was not obvious, especially chlorothalonil concentration of1×104μg/mL, the strain HTC was still able to grow well.