Authors:

Esperanza Zambrano

Date Created:

Not specified

Course Title:

Professor:

Not specified

About Paper:

Juglone is the phytotoxic allelochemical released into the soil by the black walnut tree (Juglans nigra). After being taken up by nearby susceptible plants, juglone causes oxidative stress through redox cycling. It remains unknown whether juglone's propensity to react with nucleophiles, including thiol groups in cysteine residues, also contributes to juglone's allelopathic mechanism of action. Previous work in the Widhalm lab demonstrated that juglone binds to thiol groups of cysteine residues in glutathione and the enzyme urease. Moreover, Arabidopsis plants increase expression of NAC53 and NAC78 upon exposure to juglone. These transcription factors are major regulators responsible for activating the proteosome, the enzyme complex that breaks down misfolded proteins. We are using a combination of nac53/nac78 knockout mutants, which are unable to activate their proteosome, and in vitro enzyme assays from Arabidopsis root protein extracts, to test our hypothesis that juglone broadly inhibits cellular enzyme activities and that the proteasome stress regulon is necessary to respond to juglone stress. We are also investigating other structurally similar allelochemicals for their ability to induce proteotoxicity by monitoring the expression of NAC transcription factors using qPCR. These experiments will expand our knowledge on the biochemical mechanism of action of juglone and other allelochemicals, which facilitate many plant-biotic interactions. Keywords: Juglone; Proteotoxicity; Allelopathy; Proteasome; 1,4-naphthoquinone

Source:

Purdue University / 2024

Topics:

No topics listed

Co-authors:

Esperanza Zambrano