Genetic Control of Natural Variation in Arabidopsis Glucosinolate Accumulation

Abstract

Glucosinolates are biologically active secondary metabolites of the Brassicaceae and related plant families that influence plant/insect interactions. Specific glucosinolates can act as feeding deterrents or stimulants, depending upon the insect species. Hence, natural selection might favor the presence of diverse glucosinolate profiles within a given species. We determined quantitative and qualitative variation in glucosinolates in the leaves and seeds of 39 Arabidopsis ecotypes. We identified 34 different glucosinolates, of which the majority are chain-elongated compounds derived from methionine. Polymorphism at only five loci was sufficient to generate 14 qualitatitvely different leaf glucosinolate profiles. Thus, there appears to be a modular genetic system regulating glucosinolate profiles in Arabidopsis. This system allows the rapid generation of new glucosinolate combinations in response to changing herbivory or other selective pressures. In addition to the qualitative variation in glucosinolate profiles, we found a nearly 20-fold difference in the quantity of total aliphatic glucosinolates and were able to identify a single locus that controls nearly three-quarters of this variation.

Variations in CYP74B2 (Hydroperoxide Lyase) Gene Expression Differentially Affect Hexenal Signaling in the Columbia and Landsberg erecta Ecotypes of Arabidopsis

“…The contrasting higher transcript levels in the Col ecotype (2.3-fold) of CYP83B1, which mediates synthesis of indole glucosinolates Hansen et al, 2001), suggests that compensatory interplay exists between the CYP83A1 and CYP83B1 loci as previously seen in the studies of Hemm et al (2003) and Naur et al (2003). The differential expression of CYP83A1 in these ecotypes partially explains the different basal glucosinolate profiles in the Col and Ler ecotypes (Kliebenstein et al, 2001a) and the higher overall glucosinolate content of the Ler ecotype (Jander et al, 2001). Presumably these different basal levels of glucosinolates contribute to variations in ecotype resistance to insect predators as myrosinases release toxic glucosinolate derivatives (Rask et al, 2000).…”

“…Considerable variation that, in fact, exists at the DNA sequence level results in an extensive range of phenotypic variations between these ecotypes in biochemical and morphological characteristics associated with defense responses. Examples of this variation include differences in disease resistance (Kunkel, 1996), leaf trichome density (Larkin et al, 1996), glucosinolate content (Kliebenstein et al, 2001a;Raybould and Moyes, 2001), epicuticular wax composition (Rashotte et al, 1997), and insect resistance (Jander et al, 2001). While complicating molecular analysis of this plant species, these natural variations have provided an imported genetic resource for analyzing gene functions.…”

Accurate mass error correction in liquid chromatography time-of-flight mass spectrometry based metabolomics

“…The majority of the metabolites selected for the analysis of the Arabidopsis samples in this study were glucosinolates because they give unique ion masses, i.e. they are easy to extract from the raw data and are known to be present in many different genotypes (Kliebenstein et al 2001;Reichelt et al 2002). The same criteria were applied to the selection of the metabolites from the potato series.…”

Synthetic biology of metabolism: using natural variation to reverse engineer systems

“…This stunting was associated with significant pleiotropic impacts on primary metabolism [15]. This difference in genotypes response to the transgenes was occurring even though Ler and Col-0 start off with similar glucosinolate content and the Col-0 transgenic lines accumulated higher glucosinolate [13][14][15][16][17]. This argues that the stunting is not a simple response to the cost of producing more glucosinolate.…”

“…Ler and Col-0 start off with similar glucosinolate content and the Col-0 transgenic lines accumulated higher glucosinolate [13][14][15][16][17]. This argues that the stunting is not a simple response to the cost of producing more glucosinolate.…”