Molecular analysis of resistance gene locus to bacterial canker and wilting disease in tomato mutants

The tomato plant is one of the most widely produced vegetables in the world. However, there are several disease factors which limit tomato production. The Clavibacter michiganensis subsp. michiganensis (Cmm) pathogen causes wilting and canker symptoms on the leaves of plants and bird’s eye symptoms on the tomato and then the plants completely die. Development of resistant tomato varieties is prerequisite due to absence of an effective control methods against the bacterial disease. The resistant M3-9 and M3-15 tomato plants have been developed because of mutation from susceptible NCEBR3 tomato seeds with ethyl methanosulfonate (EMS). For each chromosome of the tomato genome, 24 SSR markers were selected from each end of the haploid, 12 tomato chromosomes, and polymorphic differences between susceptible and resistant tomato plants were studied. Polymorphisms were found with SSR13 and SSRB18031 markers located on chromosome 5 with resistant mutants, M3-9, M3-15 and susceptible original NCEBR3 plants. It is envisaged that a resistance gene is located on the 5th chromosome of resistant M3-9 and M3-15 plants. Further fine mapping studies will reveal the location of the resistance gene(s) for controlling bacterial canker and wilting pathogen.