Morphological, biochemical and molecular identification of the wild strain of Agrobacterium tumefaciens from crown gall infected mango tree

Abstract

Crown gall is one of the destructive diseases that is considered to be of great economic impact due to the significant losses in mango and other stone fruit tree nurseries. The plant pathogen that causes crown gall is Agrobacterium tumefaciens. The present study was conducted to isolate and identify Agrobacterium tumefaciens from crown gall samples. These samples were collected from BAU campus, Mymensingh. The bacterium was isolated and characterized by morphological, microscopic, biochemical and confirmed by molecular test. The morphological, microscopic and biochemical tests ini- tially revealed that all the bacterial isolates are gram negative. Pathogenicity test: a carrot disc bioassay showed tumors in the plant because T-DNA of the bacteria was transferred and integrated into each of carrot disc. Antibiotic sensitivity tests revealed that the resistance to antibiotic. Moreover, DNA was isolated from infected tissue and after gel electrophoresis of PCR prod- uct, DNA band with expected 184bp was found and therefore, it was finally confirmed that the isolates were A. tumefaciens. Therefore, morphological, biochemical and PCR-based rapid detection techniques could effectively be used to detect the nature’s best genetic engineer, A. tumefaciens causing crown gall disease.