Screening Of Microorganisms Producing Chitinases With Inhibition Effect To Sclerotinia Sclerotiorum And Study On Conditions Of Enzyme Production

Plant disease and pests are most important causations affecting agriculture production in our country, it is necessary to resolve the problem that how to control them reasonably and effectively. Chitinase should not only inhibit the growth of fungi, but kill the insect as well. And chitinase has some characteristics, such as many different species and distinguishing inhibitory action. So it is important to find some chitinases, which have strong inhibition ability to pathogens and via optimizing the combination of chitinase to make them more effectively. For that, this research mainly aimed to isolate and screen strains, which should produce chitinase, from soil of rhizosphere and plant tissue. And determine the inhibition ability of the strain to Sclerotinia sclerotiorum and Curvularia lunata. Then the conditions for producing chitinases enzyme were selected. That will be helpful for us to separate and purify the chitinases, identify the character and structure, and establish the foundation of controling plant disease using chitinase engineering strain by the technique of transgene. The main results are as follows:1. For 181 strains were isolated from soil of rhizosphere and tissue of plant that can make a transparent zone on chitin selective medium. Compared the rate of strains chitinase from different source, it showed actinomycete from plant tissue was higher than microbe from soil of rhizosphere.2. Determined the inhibition action of different isolates, which secreted chitinases, to the growth of Sclerotinia sclerotiorum, it showed 41 strains had inhibiton ability, and 7 of them had high inhibition efficiency.3. Manurate inhibiton action of rude enzyme, cell free culture filtrate depositied with (NH4)2SO4, the resulted showed it had restrain effect to Sclerotinia sclerotiorum. Examined the treated mycelium, it growed abnormaly.4. The antimicrobial spectrum showed strains antagonism actinomycetes had different effect to different pathogen. Strain antagonism bacteria had inhibition efficiency to all pathogen of affording.5. Optimize condition for producing chitinase enzymes were ascertained. It showed...