Technical Abstract: Fusarium verticillioides is a non-obligate plant pathogen causing a number of maize diseases and is responsible for the production of fumonisin B1 (FB1), a potential human carcinogen and agent of fatal farm animal diseases. The effect of FB1 on the health and development of maize seedlings was recently evaluated, and FB1 was shown to disrupt biosynthesis of complex sphingolipids by inhibiting ceramide synthase. Such inhibition caused the accumulation of sphingoid bases (phytosphingosine and sphinganine) and their 1-phosphates in the roots of maize seedlings. Others have demonstrated that in Arabidopsis thaliana sphingosine-1-phosphate (S1P) and phytosphingosine-1-phosphate (Phyto1P) regulate stomatal behavior. Our objectives were to evaluate physiological effects of F. verticillioides on maize seedlings, including whether FB1 alters maize transpiration and stomatal aperture behavior. Multiple load cells within a growth chamber were used to determine differential transpiration rates between inoculated and control treatments over a two week period. Stomatal conductance was also measured using a porometer. The data sets will serve as a guide for subsequent evaluation of FB1 alone without fungal inoculation. More detailed observations of stomatal behavior will be evaluated in vitro using an epidermal peel assay. These data will provide insight into possible downstream effects of FB1 disruption of ceramide biosynthesis and resulting elevated sphingoid base concentrations in maize tissues.