Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2014 May 20;111(20):7349-54. doi: 10.1073/pnas.1321781111. Epub 2014 May 5.

Phyllotreta striolata flea beetles use host plant defense compounds to create their own glucosinolate-myrosinase system.

Author information

1
Departments of Entomology, fberan@ice.mpg.de.
2
Departments of Entomology.
3
Biochemistry.
4
Mass Spectrometry.
5
Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany;
6
Quality, Leibniz Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., 14979 Grossbeeren, Germany; and.
7
Bioorganic Chemistry, and.
8
Entomology, AVRDC-The World Vegetable Center, Tainan 74151, Taiwan.
9
Urban Plant Ecophysiology, Humboldt-Universität zu Berlin, 14195 Berlin, Germany;

Abstract

The ability of a specialized herbivore to overcome the chemical defense of a particular plant taxon not only makes it accessible as a food source but may also provide metabolites to be exploited for communication or chemical defense. Phyllotreta flea beetles are adapted to crucifer plants (Brassicales) that are defended by the glucosinolate-myrosinase system, the so-called "mustard-oil bomb." Tissue damage caused by insect feeding brings glucosinolates into contact with the plant enzyme myrosinase, which hydrolyzes them to form toxic compounds, such as isothiocyanates. However, we previously observed that Phyllotreta striolata beetles themselves produce volatile glucosinolate hydrolysis products. Here, we show that P. striolata adults selectively accumulate glucosinolates from their food plants to up to 1.75% of their body weight and express their own myrosinase. By combining proteomics and transcriptomics, a gene responsible for myrosinase activity in P. striolata was identified. The major substrates of the heterologously expressed myrosinase were aliphatic glucosinolates, which were hydrolyzed with at least fourfold higher efficiency than aromatic and indolic glucosinolates, and β-O-glucosides. The identified beetle myrosinase belongs to the glycoside hydrolase family 1 and has up to 76% sequence similarity to other β-glucosidases. Phylogenetic analyses suggest species-specific diversification of this gene family in insects and an independent evolution of the beetle myrosinase from other insect β-glucosidases.

KEYWORDS:

convergent evolution; host plant specialization

PMID:
24799680
PMCID:
PMC4034198
DOI:
10.1073/pnas.1321781111
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center