ــــــــــــــــــــــــــــــــــــــــــــــــــــــ LABORATORY STUDY FOR THE EVALUATION OF Azotobacter chroococcum EFFCIENCY IN CHITINASE PRODUCTION AND IT’S ABILITY IN CELL WALL DEGRIDATION OF Rhizoctonia solani THAT CAUSES BLACK ROOT ROT DISEASE OF STRAWBERRY PLANTS

Abstract

The objective of this research is to assess the efficiency of the bacteria Azotobacter chroococcum production of chitinase enzyme and its ability to analyze the cell walls of the fungus Rhizoctonia solani isolated from the roots of strawberry plants that causes black root rot disease of strawberry plants , this is consider as the first records of the fungus R. solani on strawberry in Iraq . The study showed the ability of the A. chroococcum to produce chitinase enzyme through of decomposition zone the colloidal chitin beneath bacterial colonies depth of 0.5 cm and were higher effectiveness of the enzyme in the fourth days of incubation at pH 8 and temperature 25 ˚C on the enzymatic production center when the concentration of the inoculum was5-10 . Studied the antagonism relationship between chitinase and R.solani which shows that the enzyme was able to inhibit the fungus on PDA with the rate of 85.14% compared to the treatment control