Plant signaling involves the transport of information within and between plant cells from receptors to effectors. Plants are affected by biotic and abiotic stress conditions like insect attack and extreme temperatures, respectively, which cause disease, the induction of senescence and the reduction of crop yield. To improve plant traits for feed, fiber, and energy applications, it is critical to understand the short- and long-range signaling mechanisms plants use to control growth, biomass composition, senescence and responses to environmental stresses. It is known that many plant signaling molecules have profound effects on plants, through mechanisms that remain largely obscure. A key gap in knowledge is the understanding of the mechanisms that govern the movement and fate of signaling molecules. This study seeks to synthesize signaling probes based on flagellin 22 (flg22), a 22-amino acid peptide that induces defense gene expression to trigger both local and systemic immune responses in plants. Solid-phase synthesis of fluorescently-tagged derivatives of flg22 was initiated, and studies on the uptake of labeled probes was conducted using a fiber-optic fluorescence microscope that was adapted for use in plants. Fluorescence microscopy showed uptake and internalization of TAMRA-flg22 in cells of Arabidopsis thaliana Columbia (wild-type strain), which was not observed in the fls2 strain in which FLS2, the receptor for flg22, had been knocked out.