| 1. |
- Outchkourov, NS, et al.
(author)
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Specific cysteine protease inhibitors act as deterrents of western flower thrips, Frankliniella occidentalis (Pergande), in transgenic potato
- 2004
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In: Plant Biotechnology Journal. - : Wiley. - 1467-7652 .- 1467-7644. ; 2:5, s. 439-448
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Journal article (peer-reviewed)abstract
- In this study, the effects of the accumulation of cysteine protease inhibitors on the food preferences of adult female western flower thrips, Frankliniella occidentalis (Pergande), were investigated. Representative members of the cystatin and thyropin gene families (stefin A, cystatin C, kininogen domain 3 and equistatin) were expressed in potato (Solanum tuberosum) cv. Impala, Kondor and Line V plants. In choice assays, a strong time- and concentration-dependent deterrence from plants expressing stefin A and equistatin was observed. Cystatin C and kininogen domain 3 were not found to be active. All tested inhibitors were equally or more active than stefin A at inhibiting the proteolytic activity of thrips, but, in contrast with stefin A, they were all expressed in potato as partially degraded proteins. The resistance of cysteine protease inhibitors against degradation in planta by endogenous plant proteases may therefore be relevant in explaining the observed differences in the deterrence of thrips. The results demonstrate that, when given a choice, western flower thrips will select plants with low levels of certain cysteine protease inhibitors. The novel implications of the defensive role of plant cysteine protease inhibitors as both deterrents and antimetabolic proteins are discussed.
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| 2. |
- Outchkourov, NS, et al.
(author)
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Engineered multidomain cysteine protease inhibitors yield resistance against western flower thrips (Franklinielia occidentalis) in greenhouse trials
- 2004
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In: Plant Biotechnology Journal. - : Wiley. - 1467-7652 .- 1467-7644. ; 2:5, s. 449-458
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Journal article (peer-reviewed)abstract
- Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripiclae), cause very large economic damage on a variety of field and greenhouse crops. In this study, plant resistance against thrips was introduced into transgenic potato plants through the expression of novel, custom-made, multiclomain protease inhibitors. Representative classes of inhibitors of cysteine and aspartic proteases [kininogen domain 3 (K), stefin A (A), cystatin C (C), potato cystatin (P) and equistatin (EIM)] were fused into reading frames consisting of four (K-A-C-P) to five (EIM-K-A-C-P) proteins, and were shown to fold into functional inhibitors in the yeast Pichia pastoris. The multiclomain proteins were expressed in potato and found to be more resistant to degradation by plant proteases than the individual domains. In a time span of 14-16 days, transgenic potato plants expressing EIMKACP and KACP at a similar concentration reduced the number of larvae and adults to less than 20% of the control. Leaf damage on protected plants was minimal. Engineered multiclomain cysteine protease inhibitors thus provide a novel way of controlling western flower thrips in greenhouse and field crops, and open up possibilities for novel insect resistance applications in transgenic crops.
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