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Novel tomatoes that counteract herbivore suppression of plant defences

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Title Novel tomatoes that counteract herbivore suppression of plant defences
Period 01 / 2009 - unknown
Status Current
URL http://www.groenegenetica.nl/pro1/general/show_document_general.asp?documentid=110&GUID=%7B1E28E53C%2D225F%2D44FF%2D86CE%2D8D77BDF7DD74%7D
Research number OND1342392

Abstract

Herbivory induces massive metabolic reconfigurations in plants. Such changes mediate tissue repair, resource allocation and defence. Induced plant-defences constitute an array of changes decreasing the plant's palatability i.e. directly via toxins and accumulation of proteins that interfere with herbivore digestion but also indirectly via volatile signals that attract the herbivore's natural enemy. However, because these defences decrease herbivore fecundity and survival they impose selection pressure on herbivores which in turn are sometimes selected to increase their resistance, something which can only happen when there is sufficient genetic variation. Indeed herbivore resistance to plant defences, as to pesticides, occurs frequently. However, recently convincing data emerged that some herbivores do not become resistant to plant defence products directly but, like some virulent pathogens, suppress host plant defences. Since the ability to sabotage host plant defences was discovered for several arthropod species independently it might well be a common phenomenon. This notion is strongly supported by the fact that we discovered inducing individuals and suppressing individuals of the tomato pest, the two-spotted spider mite Tetranychus urticae, to co-occur in the same population. Hence we selected two distinct near-isogenic mite lines via consecutive mother-son crossings, of which one performs poorly on tomato because it induces the classic JA-dependent defence-response whereas the other thrives on tomato because it suppresses those same defences and thus is referred to as being 'stealthy'. However, the stealthy strain is not stealthy in all aspects since it also up regulates genes. This provides the unique opportunity to re-establish the ability of the plant to recognize a stealthy mite via arrangement of promoters induced by stealthy-mites with suppressed potent defence genes by means of genetic engineering. We propose to clone (1) tomato promoters up regulated during stealthy mite feeding to (2) reengineer the plant's defence by fusing these promoters to the defence genes that stealthy mites suppress. We will follow two parallel research lines, one aimed at foliar defence genes and promoters (PART I), the other at trichome specific genes and promoters (PART II). Plants with a (partially) restored defence response to stealthy mites we will test for their performance during infestation with other herbivores, for pathogen resistance and fruit production. This research program will highly enrich our fundamental understanding of how plant-herbivore interactions are disrupted by adaptations and undertakes a major step forward by applying genetic engineering as a means to counter natural variation in herbivores and to rearrange the plant's natural regulatory machinery such that insects feeding under the radar are detected again.

Related organisations

Secretariat Keygene N.V.
Collaboration University of Amsterdam (UvA)
Commissioner TTI Green Genetics

Other involved organisations

Keygene NV

Related people

Researcher Prof.dr. M.A. Haring
Researcher Dr. M.R. Kant

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