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Title:The glucosinolate/myrosinase system: variation in glucosinolates, hydrolysis products, transcript abundance, and quinone reductase bioactivity in Brassica sp. crops
Author(s):Becker, Talon M
Director of Research:Juvik, John A
Doctoral Committee Chair(s):Juvik, John A
Doctoral Committee Member(s):Jeffery, Elizabeth H; Huber, Steven C; Briskin, Donald P
Department / Program:Crop Sciences
Discipline:Crop Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Glucosinolate
Myrosinase
Quinone reductase (QR)
NAD(P)H quinone reductase 1 (NQO1)
Methyl jasmonate (MeJa)
Abstract:Glucosinolates, and more specifically their hydrolysis products, are secondary metabolites present in Brassica crops that are important for plant defense from insects and pathogens. In addition, these compounds have long been associated with anti-cancer activity in mammals through the induction of phase II detoxification enzymes, among other mechanisms. For this reason, the improvement of anti-cancer activity through selective breeding of edible plants that produce glucosinolates, such as the Brassica, has gained in popularity as a breeding objective. In this research we survey variation in glucosinolate and glucosinolate hydrolysis product profiles as well as anti-cancer activity in a range of Brassica crops in an attempt to identify differences, if any, in the underlying agents of anti-cancer activity in these crops. Also, we have investigated how environmental effects and interactions between the environment and genetic background of the plant influence glucosinolates, their hydrolysis products, and anti-cancer activity in an attempt to better understand the feasibility of breeding for anti-cancer activity. It was found that environmental effects on anti-cancer activity may be too great to allow for direct breeding for this trait. However, the data suggest that breeding for individual GSs and GSHPs known to influence anti-cancer activity is feasible. With this is in mind, predictive models were built using gene transcript abundance data for genes associated with the glucosinolate/myrosinase system in an attempt to predict final phytochemical phenotypes in broccoli. It was found that models built using gene transcript abundance as predictors delivered satisfactory predictive ability for phytochemical phenotypes collected in the same growing season as the transcript abundance data, but that ability did not hold across growing seasons, at least in the two growing seasons associated with this study. Lastly, we examined the effect of methyl jasmonate (MeJA) elicitation on the transcript levels of glucosinolate/myrosinase system genes in broccoli. MeJA treatment showed significant effects on transcript abundance for a number of the surveyed genes, although varietal and environmental effects also influenced transcriptional response to MeJA. Also, many genes showed positive and negative dosage responses in transcript abundance to increasing concentrations of MeJA within the cultivar Green Magic grown in 2010.
Issue Date:2015-10-27
Type:Thesis
URI:http://hdl.handle.net/2142/89184
Rights Information:Copyright 2015 Talon Becker
Date Available in IDEALS:2016-03-02
Date Deposited:2015-12


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