Abstract Detail



Physiology & Ecophysiology

Tuominen , L.K. [1], Reicholf, Rebecca [2], Drenovsky, Rebecca [3].

Scale-Down of Extraction Method and Validation of Assay to Quantify Total Glucosinolates in Brassicaceous Gypsum Endemics.

Glucosinolates are plant secondary metabolites found in fifteen families within the order Brassicales.  These metabolites consist of a thioglucose moiety, a sulfonated oxime, and an organic side chain that varies, yielding well over a hundred known structures.  Spatially separated from the enzyme myrosinase in vivo, glucosinolates have evolved primarily as defense compounds that are enzymatically broken down during herbivory to yield thiocyanates and isothiocyanates.  These end products give cruciferous vegetables, such as broccoli and turnips, their characteristic flavors.
Glucosinolates in crop plants are typically quantified and individual structures identified using HPLC-MS.  However, lower-cost assays requiring less specialized equipment and expertise are more broadly accessible for initial screening of total glucosinolate concentrations in native species.  We have therefore simplified and scaled down a published method for methanolic extraction, partial purification via anion exchange, and colorimetric quantification of total glucosinolates.  Our modifications reduce reagent consumption to as little as 20% of the full-scale assay, and initial tests achieved successful quantification using 30% of the dry mass previously reported.  We report standard assay validation measures using sinigrin standards, cabbage (Brassica oleracea var. oleracea), Asian greens (Brassica rapa var. chinensis), radish leaf (Raphanus raphanistrum ssp. sativus), garden cress (Lepidium sativum), and spinach (Spinacia oleracea, negative control).
This modified method will be applied in a new line of research evaluating the potential adaptive value of glucosinolates to Brassicaceae endemic to gypsum (CaSO4 ∙ 2H2O) soils of the northern Chihuahua desert.  We outline a screening and quantification strategy for efficient use of limited sample tissue containing unknown glucosinolate concentrations to support initial testing.


1 - John Carroll University, Department of Biology, 1 John Carroll Blvd, University Heights, OH, 44118, USA
2 - John Carroll University, Chemistry Program, 1 John Carroll Blvd, University Heights, OH, 44118, USA
3 - Biology Department, 1 John Carroll Blvd, University Heights, OH, 44118, United States

Keywords:
Brassicaceae
edaphic adaptation
Glucosinolates
gypsum
method development
phytochemical assay
Specialized metabolism
sulfur.

Presentation Type: Poster
Number: PPE008
Abstract ID:750
Candidate for Awards:None


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