Towards restricting the spread of bacterial diseases in Palestine: Diagnosis of Agrobacterium tumefaciens in soil samples from stone fruit nurseries in three regions of the West Bank

Osama Al-abdallah
Naim Iraki
Naser Jaghoub

Agrobacterium. tumefaciens is a soil borne pathogen infecting a wide range of cultivatedcrops and causes the crown gall disease (Jun Z et al 2000, Matthew A. E et al 2003) . Thisdisease causes a remarkable economic loss, especially when it affects trees (Kennedy B. etal1980) . A large part of the loss could be prevented if an appropriate phytosanitary strategiesare employed. Continuous testing of the cultivation medium and the seedlings for thepresence of this pathogen followed by an eradication of the infected material would have acrucial role in restricting the spread of this disease.Soil samples were collected from different commercial stone fruit nurseries located in threeregions; north, midwest, and south of the West Bank and they were tested for A.Tumefaciens. Aliquots of 100 μl from soil suspension were inoculated on semi-selectivemedia. Typical colonies developed on this selective medium were subjected to molecularbased diagnosis for A. tumefaciens using PCR techniques. The diagnosis employed specificprimers for the ipt gene located on the Ti plasmid (T-DNA) of the A. tumefaciens ( HaasJ.H. et al 1995, Cubero J. 1999 )A total of 200 samples from all areas were tested. In the North, 21 out of 129 samples werefound to be infected. In the South, 11 out of 59 samples showed infection withAgrobacterium. In the Midwest, however, only 12 samples were tested and only one of themwas infected. The percentage of infection is almost at the same level in the North and theSouth, 16 and 18%, respectively. Whereas, in the Midwest, the infection level was muchlower, but this value is not reliable due to the small number of tested samples.In conclusion, the results indicate a remarkable rate of infection with Agrobacteriumtumefaciens in commercial nurseries producing stone fruit seedlings. This implies that amore severe monitoring measures should be implemented by the Palestinian Ministry ofAgriculture to assure the use of certified plant sources and sterilized culture media.