A lasting crop ‘resistance’ to insect was achieved by altering the morphology of the flower. The research is based on the knowledge of insect life cycle in relationship with the flower morphology. The bright petals attract insects and the flower is used as a mating place or for feeding source of pollen and nectar. The life cycle of thrips (Frankliniella occidentalis) on their host cucumber, used as a model plant, was drastically interrupted by changing the identity of the yellow petals into green sepals, resulting in a reduced insect reproduction efficiency. In the absence of the attractive yellow flowers, thrips insects will be less successful in finding a mating partner.
The researchers created a homeotic mutant of cucumber (the green petals mutant) which produces green sepals instead of yellow petals. The alteration of the flower morphology was achieved by the manipulation of the expression of a floral class B homeotic gene CUM26 (Kater et al., 2001). In principle class B mutants can be quickly identified and engineered in every plant by inhibiting the function of B genes.
Stage of Development
Green house before commercialization.
Reasons for Block/Delay
Excessive costs (when compared to potential market) to produce the dossier for the approval.
Frankliniella occidentalis is one of the major insect pests throughout greenhouse crops in Europe, the USA and Canada. The damage caused by this insect are direct (feeding punctures and necrosis) and indirect (fruit malformation and transmission of plant viruses). The insect is found on a wide range of plants such as cucumber, tomato, carnation, rose, cotton and many others.
To date, chemical agents for crop protection remain the only solution, despite the impact that they may have on the environment. The GE strategy is an environmentally friendly method and a much better alternative to any treatment.
The GE strategy can be used for several plant-insect combinations, in particular for parthenocarpic fruits such as cucumber, tomato, melon and eggplant. Because the molecular nature of this homeotic mutation is known and very conserved among flowering plants, this mutant can be easily phenocopied in other species by genetic modification
Reference to Publication
Kater, M.M., Franken, J., Carney, K., Colombo, L. and Angenent, G.C. (2001). Sex determination in cucumber is defined to specific floral whorls. Plant Cell, 13, 481–493.
Kater, M.M, Franken, J., Ingammer, H., Gretenkort, M., van Tunen, A.J., Mollema, C. and Angenent, G.C. (2003). The use of floral homeotic mutants as a novel way to obtain durable resistance to insect pests. Plant Biotechnol Journal, 1, 123-7.
Martin M. Kater, Dipartimento di Genetica e Biologia dei Microrganismi, Via Celoria 26, 20133 Milan, Italy;