Translocation of sphingoid bases and their 1-phosphates, but not fumonisins, from roots to aerial tissues of maize seedlings watered with fumonisins

In an earlier study using maize seedlings grown from kernels inoculated with Fusarium verticillioides, fumonisin B(1) (FB(1)) was preferentially accumulated in leaf tissue compared to FB(2) and FB(3). The present study tested whether maize seedlings preferentially translocate FB(1) when plants are watered with FB(1) and/or FB(2), without the fungus present. The results show that neither FB(1) nor FB(2) was translocated when administered in the watering solution, and although both FB(1) and FB(2) were taken up by the roots, the accumulation of FB(2) in roots was significantly less than expected, indicating that FB(1) was preferentially accumulated. In addition, there was clear evidence of ceramide synthase inhibition in the roots and sphingoid base and sphingoid base 1-phosphates accumulated in leaf tissue presumably due to translocation from the roots. These findings suggest that the fungus-plant interaction is necessary for FB(1) translocation in maize seedlings infected with F. verticillioides.