A barley cysteine-proteinase inhibitor reduces the performance of two aphid species in artificial diets and transgenic A
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ORIGINAL PAPER
A barley cysteine-proteinase inhibitor reduces the performance of two aphid species in artificial diets and transgenic Arabidopsis plants ´ lvarez-Alfageme Laura Carrillo • Manuel Martinez • Fernando A • • • Pedro Castan˜era Guy Smagghe Isabel Diaz Fe´lix Ortego
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Received: 3 March 2010 / Accepted: 4 June 2010 / Published online: 22 June 2010 Ó Springer Science+Business Media B.V. 2010
´ lvarez-Alfageme G. Smagghe F. A Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
was to analyze the effects of the whole gene family members of barley cystatins against two aphids, Myzus persicae and Acyrthosiphon pisum. All the cystatins, except HvCPI-7, HvCPI-10 and HvCPI-12, inhibited in vitro the activity of cathepsin L- and/or B-like proteinases, with HvCPI-6 being the most effective inhibitor for both aphid species. When administered in artificial diets, HvCPI-6 was toxic to A. pisum nymphs (LC50 = 150 lg/ml), whereas no significant mortality was observed on M. persicae nymphs up to 1000 lg/ml. The effects of HvCPI-6 ingestion on A. pisum were correlated with a decrease of cathepsin B- and L-like proteinase activities. In the case of M. persicae, there was an increase of these proteolytic activities, but also of the aminopeptidaselike activity, suggesting that this species is regulating both target and insensitive enzymes to overcome the effects of the cystatin. To further analyze the potential of barley cystatins as insecticidal proteins against aphids, Arabidopsis plants expressing HvCPI6 were tested against M. persicae. For A. pisum, which does not feed on Arabidopsis, a combined dietVicia faba plant bioassay was performed. A significant delay in the development time to reach the adult stage was observed in both species. The present study demonstrates the potential of barley cystatins to interfere with the performance of two aphid species.
Present Address: ´ lvarez-Alfageme F. A Agroscope Reckenholz-Ta¨nikon Research Station, Reckenholzstrasse 191, 8046 Zu¨rich, Switzerland
Keywords Aphid Artificial diet Cathepsin Cystatin Cysteine-proteinase Transgenic plant
Abstract Cystatins from plants have been implicated in plant defense towards insects, based on their role as inhibitors of heterologous cysteine-proteinases. We have previously characterized thirteen genes encoding cystatins (HvCPI-1 to HvCPI-13) from barley (Hordeum vulgare), but only HvCPI-1 C68 ? G, a variant generated by direct-mutagenesis, has been tested against insects. The aim of this study
L. Carrillo P. Castan˜era F. Ortego (&) Departamento de Biologı´a Medioambiental, Centro de Investigaciones Biolo´gicas, CSIC, Ramiro de Maeztu, 9, 28040 Madrid, Spain e-mail: [email protected] L. Carrillo M. Martinez I. Diaz Centro de Biotecnologı´a y Geno´mica de Plantas (UPM-INIA) Campus Montegancedo, Universidad Polite´cnica de Madrid, Autopista M40 (km 38), Pozuelo de Alarco´n, 28223 Madrid, Spain
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Introduction Aphid
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