Abstract
We reported formerly that cyclamen plant grown under excess nitrogen induces Fusarium wilt disease and that both glutamine and asparagine formed in the underground parts of cyclamen significantly promote the growth of infected Fusarium. The present investigation was undertaken to examine the possibility of polyamines as a diagnostic marker of the wilt disease. When cyclamen plants were inoculated with Fusarium oxysporum f.sp. cyclaminis, the levels of leaf putrescine and spermidine, but not spermine, increased only nine days after inoculation where the wilting of the leaves is not evident. The degree of Fusarium infection into cyclamen tubers closely related to the wilting of their leaves, and tubers stained with Fusarium contained much higher levels of polyamine than healthy one. Furthermore, the leaf polyamine contents positively correlated with the tuber polyamine contents, indicating that leaf polyamine, especially putrescine and spermidine, is a useful diagnostic marker of Fusarium infection.
