Determining the expressions of possible genes related to resistance mechanism against bacterial cancer and the wilt diseases in tomatoes

A bacterium, Clavibacter michiganensis subsp. Michiganensis (Cmm), causes bacterial canker and wilt disease on tomato. Resistance to disease is controlled by multiple genes and those genes are present in wild tomato varieties (Solanum pimpinellifolium, Solanum hirsutum ve Solanum peruvianum). The host responses to Cmm and molecular mechanisms associated with the development of disease symptoms are largely unexplored. To investigate plant responses activated during Cmm infection, the changes in host gene expression during disease development were analyzed in resistant lines (LA 407, LA 2157) and susceptible lines (BATEM and Moneymaker) and F1 population crossing between LA 2157 and BATEM. The seedlings of resistant and susceptible lines and F1 populations were inoculated by 10 high virulence effects of Cmm mixture isolates, collecting from different part of Turkey and water as a control. The shoot part, 1cm above and below of the inoculation point were taken 1, 2, 4, 6, 8 10, 12 hour and 1, 2, 4, 6, 8, 10 , 12 days after Cmm inoculation and expression of the 16 genes involved in basal defence responses were analyzed by real-time PCR. The LA 2157 and LA 407 lines were more resistant to Cmm than BATEM and Moneymaker lines. Furthermore, LA 2157 line was found to be most resistant line againist to Cmm according to severity of symptom. The induction of gene expression for ERF/AP2, Pti5, ACO1, chitinase, W-IP Sn-1, extensine, K-1 TF genes in both early and late time after Cmm inoculation, proved that these genes might be effective in resistancy mechanism. Although the expression of VWP gene in succeptible lines (Moneymaker and Batem) induced in early stage of Cmm inoculation, the expression of VWP gene in resistant line, LA 2157 induced in late time after inoculation. Therefore, it can be suggested that the VWP gene may play a role in succeptible response and basal defence mechanism. Furthermore, induction of EIX R1 gene expression in early time point in resistant lines (LA 2157 and LA 407) showed that this gene might be associated with basal defence response to Cmm.