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Aphids (4,000
species) are responsible for a great deal of damage, especially in
temperate regions where they are the principal cause of devastation in
numerous plant species. These biting-sucking insects feed on the
phloem sap of plants and depreciate the quality of agricultural
products. Several viruses circulate in the phloem and aphids are
efficient vectors for them, causing major epidemics of virus
diseases.
The loss in yields for agriculture is difficult to evaluate becase it
is dependent on species, crops, regions and countries. For example,
aphids of cereal plants may lead to losses of 30% in wheat crops
(draining of sap, depreciation of agricultural products) and up to 50%
in barley (viral diseases) in France.
There have been multiple failures in the fight against these aphids,
due to the appearance of clones which are resistant to insecticides or
which can overcome plant resistance, or lead to an increase in virus
diseases. The identification of genes which are markers for the
destructive potential of aphids should lead to the discovery of future
targets for the development of new active molecules.
Furthermore, because of their unique
characteristics, aphids constitute a choice biological material for
approaching important questions of theory and experimentation in
evolutionary biology such as the evolution of reproductive systems
(asexual-sexual) or symbiosis (endosymbiotic bacteria).
Aphid genomics has been an example of a collaborative international
network structure from the beginning, as evidenced by the presence of
foreign groups in this project. France is one of the leaders of this
network.