Authors' Affiliations

Bernard Abakah, Department of Chemistry, College of Arts and Sciences, East Tennessee State University, Johnson City, TN. Thomas Ntim, Department of Chemistry, College of Arts and Sciences, East Tennessee State University, Johnson City, TN. Edward Offei, Department of Chemistry, College of Arts and Sciences, East Tennessee State University, Johnson City, TN. Christopher Erb, Department of Chemistry, College of Arts and Sciences, East Tennessee State University, Johnson City, TN. Jessica Morgan, Departments of Biophysical Sciences, University of Chicago, Chicago IL. Dian Liu, Departments of Biochemistry & Molecular Biophysics University of Chicago, Chicago IL. Joanna Jelenska, Departments of Molecular Genetics & Cell Biology, University of Chicago, Chicago IL. Jennifer L. Morrell-Falvey, Oak Ridge National Laboratory, Oak Ridge, TN. Jean T. Greenberg, Departments of Biophysical Sciences, and Molecular Genetics & Cell Biology, University of Chicago, Chicago IL. Robert F. Standaert, Department of Chemistry, College of Arts and Sciences, East Tennessee State University, Johnson City, TN.

Location

Culp Room 304

Start Date

4-6-2022 1:00 PM

End Date

4-6-2022 2:00 PM

Faculty Sponsor’s Department

Chemistry

Name of Project's Faculty Sponsor

Robert Frank Standaert

Additional Sponsors

Dr. Greg Bishop, Dr. Dhirendra Kumar, Dr. Jean Greenberg

Classification of First Author

Graduate Student-Master’s

Competition Type

Competitive

Type

Oral Presentation

Project's Category

Molecular Recognition, Stress Response, Amino Acids, Chemical Synthesis, Ligands, Organic Chemistry, Fluorescence, Microscopy

Abstract or Artist's Statement

Plants secrete peptide ligands and use receptor signaling to respond to stress and control development. Understanding the signaling mechanisms and associated molecular trafficking is key to improving plant health and productivity for food, fiber and energy applications. However, one of the challenges to elucidating communication pathways in plants is to study the trafficking of molecules and signals iteratively and non-destructively.

This study focuses on using fiber-optic fluorescence microscopy to image live plants iteratively and non-destructively after delivering both labeled and unlabeled phytosulfokine (PSK) into the plant. PSK is a sulfated peptide hormone involved in the regulation of plant cell division and growth via specific receptors, PSKRs. It also plays a role in regulating how plants are able to tolerate stress conditions.

The microscope provides two-color (FITC/TRITC) optics and provides high-resolution (3–5 µm) epifluorescence micrographs via a 1-m coherent imaging fiber and a GRIN objective lens. To obtain high-quality images, the fiber was mounted either to a conventional upright microscope body equipped with a leaf compressor, or to a leaf clip with 5-axis positioning (X–Y–Z plus pitch and yaw) mounted on an extensible arm.

PSK and TAMRA-labelled PSK were delivered into the roots of various Arabidopsis thaliana genotypes (wt; receptor-deficient: pskr1/pskr2; and tagged receptor overproducing: PSKR1‑GFP), and their movement in roots and leaves was tracked with the fiber-optic fluorescence microscope.

Peptide trafficking was successfully observed in live plants non- destructively, confirming that PSK is mobile in both wt and receptor-deficient plants. Preliminary results suggest that the level of receptor PSKR1 may change in response to PSK, and that levels of PSKR1, PSKR2 or both may impact the trafficking of PSK. Understanding how PSK is trafficked in plants will offer insights into how we can improve plants health and productivity.

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Apr 6th, 1:00 PM Apr 6th, 2:00 PM

Non–Destructive Imaging of Phytosulfokine Trafficking Using a Fiber–Optic Fluorescence Microscope

Culp Room 304

Plants secrete peptide ligands and use receptor signaling to respond to stress and control development. Understanding the signaling mechanisms and associated molecular trafficking is key to improving plant health and productivity for food, fiber and energy applications. However, one of the challenges to elucidating communication pathways in plants is to study the trafficking of molecules and signals iteratively and non-destructively.

This study focuses on using fiber-optic fluorescence microscopy to image live plants iteratively and non-destructively after delivering both labeled and unlabeled phytosulfokine (PSK) into the plant. PSK is a sulfated peptide hormone involved in the regulation of plant cell division and growth via specific receptors, PSKRs. It also plays a role in regulating how plants are able to tolerate stress conditions.

The microscope provides two-color (FITC/TRITC) optics and provides high-resolution (3–5 µm) epifluorescence micrographs via a 1-m coherent imaging fiber and a GRIN objective lens. To obtain high-quality images, the fiber was mounted either to a conventional upright microscope body equipped with a leaf compressor, or to a leaf clip with 5-axis positioning (X–Y–Z plus pitch and yaw) mounted on an extensible arm.

PSK and TAMRA-labelled PSK were delivered into the roots of various Arabidopsis thaliana genotypes (wt; receptor-deficient: pskr1/pskr2; and tagged receptor overproducing: PSKR1‑GFP), and their movement in roots and leaves was tracked with the fiber-optic fluorescence microscope.

Peptide trafficking was successfully observed in live plants non- destructively, confirming that PSK is mobile in both wt and receptor-deficient plants. Preliminary results suggest that the level of receptor PSKR1 may change in response to PSK, and that levels of PSKR1, PSKR2 or both may impact the trafficking of PSK. Understanding how PSK is trafficked in plants will offer insights into how we can improve plants health and productivity.