BIOLOGICAL CONTROL OF SOIL-BORNE PHYTOPATHOGENS IN POTATO FIELDS

Abstract

Biocontrol depended on the use of microorganisms to inhabit plant diseases caused by pathogenic fungi present a reliable alternative to common strategies especially chemical fungicides, which have raised serious concerns of food contamination and environmental pollution. Microorganisms, which secrete a complex of mycolytic enzymes, are possible biological control agents of plant diseases; chitinase plays an important role in the biocontrol of plant pathogenic fungi. Most of the known rhizobacteria that serve as biocontrol agents produce and excrete chitinase. The chitinase enzymes produced by these organisms hydrolyze the chitin polymer present in the cell wall and degrade the fungal mycelia. Genes encoding for these chitinases have been cloned from various bacterial and fungal species. The isolated gene coding for the chitinase can be transferred into another biocontrol agent producing secondary metabolite or introduced into different plant species in order to enhance resistance against a broad range of fungal pathogens. The major aims of this study were isolation, identification, molecular characterization and study the antagonistic activity of the potent broad spectrum local chitinolytic bacterial isolates against soil borne pathogenic fungi, evaluation of their antagonistic activity against Rhizoctonia solani and Fusarium oxysoprum. Detection, Isolation, and nucleotides sequence of ChiA gene from the most potent isolate.