بررسی توانایی آنتاگونیستی چند جدایه Pseudomonas spp. در کنترل بیماری شوره سیاه سیب زمینی

Potatoes are the fourth most important in the world, as well as the most important non-cereal products. Because of the supply of energy, is a suitable substitute for wheat and it is a great of importance in the diet of the community. Rhizoctonia solani (potato dandruff ) is one of the most important post_harvest diseases of potato,causing significant damage to the product each year. The use of chemical pesticides is always associated with environmental hazards,therefore ,the greatest attention of the researcher is to control biologic. Biological control of this paitent with compound containing Pseudomonas isolates is a proposed strategy to reduce the risk of harm and replacement to toxic pesticides. Pseudomonas are capable of causing positive changes in plant growth,root and colonization due to the use of bacteria from various nutrient. In this research, several pseudomonas strains isolated from rhizosphere of different farms and gardens were used. At first,the antagonistic effects of Pseudomonas bacteria were evaluataed using bacterial culture against Rhizoctonia fungus in a PDA medium under laboratory conditions. The results showed that 32 isolates had significant antagonistic effects against these fungi.Among them,the isolates(pf2,pf4,pf8,pf14,pf23,pf28,pf29) were able to produce an inhibitory halo of more than 5mm and isolates( pf5,pf9pf11,pf15,pf17,pf23) the inhibitory halo was more than 8mm and the isolates ( pf7,pf19,pf21,pf24,pf30) had a hole greater than 1.2cm. This test was conducted in a completely randomized design with 3 replications. In the following ,the antagonistic ability of the superior isolates that were able to control R.solani AG3 was studied in control of two potato fungal pathogens: R.solani AG1A, F.culmorum.The analysis of protease, chitinase, cellulase and amylase enzymes was also carried out. The result showed that all isolates were able to produce protease enzymes with the highest production in isolates (pf21, pf24, pf30). The results of the production of chitinase enzyme in all isolates except pf21, pf22, and pf23 were positive.The results of cellulase test showed that isolates(pf9,pf14,pf19,pf2,pf24,pf30,pf22,pf23) have the only production capacity of this enzyme. Finally, the result of amylase test, which were the only isolates(pf4,pf8,pf9,pf17,pf19, pf21,pf24, pf22,pf23),were positive for amylase and other isolates did not have the ability to produce this enzyme. Overall the results of this study showed the isolates of pf19,pf7,pf30,pf21,pf24 are more effective than other bacteria isolates in fungal pathogenic biocontrol. A general review of the enzymatic test in superior isolates indicates that all isolates are capable of producing protease enzymes. Therefore, we can determine the antagonistic production of these enzymes. Precise molecular detection of superior antagonists is under consideration