Cardenolide and glucosinolate accumulation in shoot cultures of Erysimum crepidifolium Rchb .
- PDF / 948,989 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 80 Downloads / 141 Views
PLANT TISSUE CULTURE
Cardenolide and glucosinolate accumulation in shoot cultures of Erysimum crepidifolium Rchb. Elisa Horn 1 & Yvonne Kemmler 1 & Wolfgang Kreis 1 & Jennifer Munkert 1 Received: 16 September 2020 / Accepted: 27 October 2020 / Editor: Gregory Phillips # The Author(s) 2020
Abstract Erysimum crepidifolium Rchb. is one of the few Brassicaceae species accumulating glucosinolates as well as cardenolides. This is possibly providing a selective advantage in evolution as both compounds are part of a chemical defense system. In order to study the biosynthesis of these compounds, a regeneration protocol for E. crepidifolium using in vitro shoot cultures derived from seeds has been developed. Murashige and Skoog (MS) culture medium supplemented with various combinations of cytokinins and auxins was used. MS medium containing NAA (naphthaleneacetic acid, 0.04 mg mL−1) and BAP (6-benzylaminopurine, 0.2· 10−2 mg mL−1) proved to be optimal for root formation. Plantlets developed well on modified MS medium without the use of phytohormones. About 80% of the plantlets rooted in vitro developed into intact plants after transfer to the greenhouse. Cardenolides (1.75 mg g−1 dry weight (DW)) were detected in cultured shoots on solid DDV media while glucosinolates mainly accumulated in roots where 0.025 mg g−1 FW were detected in shoots cultured on the same medium (DDV). The expression of two progesterone 5β-reductase and three Δ5-3β-hydroxysteroid dehydrogenase genes were measured in shoot cultures since the encoded enzymes are supposed to be involved in cardenolide biosynthesis. E. crepidifolium shoot cultures propagated on solid media meet the necessary requirements, i.e., clonal homogeneity, product accumulation, and gene expression, for a suitable model to study cardenolide but not glucosinolate biosynthesis. Keywords Erysimum crepidifolium Rchb. . Regeneration . Glucosinolates . Cardenolides
Introduction Arabidopsis thaliana (L.) Heynh., a member of the Brassicaceae family, is widely used as a model organism in genetic studies. The genus Erysimum L. belongs to the same family and comprises more than 200 species (Bailey et al. 2006; Polatschek 2013a, b). The production of cardenolides by species in the genus Erysimum is one of the best-studied examples of an evolutionarily recent gain of a novel chemical defense (e.g., Jaretzky and Wilcke 1932; Makarevich et al. 1994; Züst et al. 2020). Most Brassicaceae species accumulate glucosinolates which are activated by myrosinases to produce repellent mustard oils (Fig. 1; Fahey et al. 2001). However, several herbivores have evolved to overcome this defense * Jennifer Munkert [email protected] 1
Pharmaceutical Biology, Department of Biology, Friedrich-Alexander-University, Staudtstr. 5, D-91058 Erlangen, Germany
mechanism (Winde and Wittstock 2011). Cardenolide biosynthesis may have evolved further since the ‘mustard oil bomb’ (Matile 1980) to provide a new type of repellent. In fact, several glucosinolate-adapted beetles refused to feed on dietary cardenolides at
Data Loading...
