Crown gall disease of Lawson cypress caused by Agrobacterium tumefaciens in Iran

Lawson Cypress (Chamaecyparis lawsoniana), is an evergreen native tree to USA and Europe, also is an important amenity tree widely planted in gardens and parks throughout the country and forests of northern Iran. An alert concerning new disease in nurseries of Lawson cypress has received in Mazandaran Province. In this research during sampling process of 2018, a typical crown gall disease was found on crown of Lawson cypress seedlings in a major Lawson cypress -growing area in Mazandaran Province of Iran. Bacterial colonies were purified and selected for investigation based on biochemical, pathogenicity tests and molecular technique after isolation of bacterium using conventional bacteriological methods. Pathogenicity test of all strains on carrot discs were evaluated positive. According to biochemical and physiological characteristics and also approving by specific primers isolates identified as A. tumefaciens. We report in this study for the first time the occurrence of crown gall disease caused by Agrobacterium tumefaciens on Lawson cypress worldwide.