Graduate Student East Tennessee State University Johnson City, Tennessee
Body of Abstract: The adaptation of plants to stressful environmental conditions such as drought, flooding, high soil salinity, and extreme temperatures is made possible through intricate signaling pathways, often involving plant peptide hormones. These peptide hormones are transported throughout the plant to elicit stress responses. One such hormone is phytosulfokine (PSK), a five-amino acid hormone that plays a role in regulating cell division, cell growth, and stress response by binding to specific phytosulfokine receptors (PSKRs) on the cell surface. Understanding how plants adapt to environmental stress is vital for enhancing crop resilience, especially for energy applications. However, the ability to study peptide movement and signaling responses in plants in a non-destructive manner still remains a major challenge. This study focuses on the utilization of fiber-optic fluorescence microscopy to unravel PSK trafficking in Arabidopsis thaliana (A. thaliana). The microscope is equipped with dual-color optics and an objective lens connected to a 1-m coherent imaging fiber. The roots and leaves of different genotypes of A. thaliana, including the wild type (wt), plants deficient in PSK receptors (pskr1/pskr2), and plants expressing a fluorescently labeled PSK receptor (PSKR1-GFP), were subjected to the administration of both PSK and TAMRA (5-Carboxytetramethylrhodamine)-labeled PSK, and their movement was subsequently tracked in real-time with the microscope. The mobility of PSK in plants was confirmed through high-resolution (3–5 µm) epifluorescence micrographs. Additionally, the observed levels of PSKR1, PSKR2, or both suggest a potential influence on the trafficking of PSK within the plant.