Doctoral Dissertations
Date of Award
5-2021
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Biochemistry and Cellular and Molecular Biology
Major Professor
Tessa Burch-Smith
Committee Members
Gladys Alexandre, Barry Bruce, Brad Binder, Tarek Hewezi
Abstract
Communication is an essential component to all living organisms. In
plants, the additional cell wall surrounding each cell adds a layer of complexity
not observed in animals. To overcome the literal wall separating cells, plants
have evolved specialized pores to connect adjacent cells. Plasmodesmata (PD)
allow plants to have a continuous cytoplasm between cells. Although
plasmodesmata may appear simple and lack regulation, their structural
components and their regulatory machinery is complex and not well understood.
Organelle-to-nucleus-to-plasmodesmata signaling (ONPS) have been worked as
a leading model for a possible regulatory mechanism. Many of the details of
organelle-to-nucleus retrograde signaling pathways have been elucidated in
yeast, mammalian and plant model systems. Understanding mechanisms of
chloroplast-to-nucleus signaling will help elucidate the functions of retrograde
signaling in all organisms including bacteria and apicomplexans. Our previous
work with mutants lacking the chloroplast RNA helicase ISE2 indicates that
chloroplasts are important regulators of plant intercellular communication and
trafficking mediated by pores in the plant cell walls called plasmodesmata. Loss
of ISE2 has suggested defects in glucosinolates and in this dissertation we show
how glucosinolates can regulate intercellular trafficking via plasmodesmata. I
uncover the potential pathway of how the changes in the chloroplast by the loss
of ISE2 modulate nuclear signaling and ultimately disrupts the biosynthesis of
glucosinolates. I find that plants overexpressing ISE2 results in global
physiological defects that can partially be described as auxin defects. However, they are a more complex phenomenon. Further, I reveal that the addition of
glucosinolates alone to plants results in an increase in intercellular trafficking in a
dose-dependent manner.
Recommended Citation
Fernandez, Jessica C., "Regulation of plasmodesmata by specialized metabolites glucosinolates in Arabidopsis thaliana. " PhD diss., University of Tennessee, 2021.
https://trace.tennessee.edu/utk_graddiss/6707