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Abstract
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| The aim of this study has been to assess the potential effects as defence proteins of the whole protease inhibitor gene family from barley on arthropod pests. This family comprises 13 genes encoding proteins, cystatins (HvCPI-1 to HvCPI-13), able to specifically inhibit cysteine-proteases of the papain C1A and legumain C13 classes from plants. Besides their function as endogenous regulators of the protein turn-over, cystatins can play a role in defence due to their capability to inhibit proteases from heterologous pests and pathogens. In addition, the protective action of the barley cystatins is also supported by their induction of some of them in response to arthropod damage, wounding and after treatments with salicylic and jasmonic acids. The in vitro inhibitory activity of the 13 cystatins, purified as recombinant protein from E. coli cultures, was tested against five species of phytophagous arthropods with cysteine protease activity, mainly located in their guts: two aphids, Myzus persicae and Acyrthosiphon pisum, two coleopteran Leptinotarsa decemlineata and Diabrotica virgifera and one acari, the two-spotted spider mite Tetranychus urticae. Enzymatic activities present in these arthropods were inhibited by most of the barley cystatins, being cathepsin L-like the preferential target of these proteins. It resulted particularly efficient the recombinant protein HvCPI-6 able to drastically reduce cathepsin-L and B-like activities in the insects and acari tested. Bioassays using the two aphids reared on artificial diets supplemented with the HvCPI6 cystatin revealed a strong increase in the mortality rates of A. pisum while M. persicae was not affected. However, clear changes although different, in the cysteine proteases activity of both aphids are detected and support the different impact of the cystatins in each species. The in vivo effects of transgenic plants over-expressing the barley cystatin on the arthropods tested are currently being analysed. | |
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International
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No |
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Congress
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IOBC Working Group Induced resistance in plants against insects and diseases |
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960 |
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Place
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Granada, España |
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Reviewers
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Si |
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ISBN/ISSN
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Start Date
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12/05/2009 |
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End Date
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16/05/2009 |
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From page
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1 |
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To page
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0 |
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IOBC/WPRS Bulletin |