Phylloxera Genome Project

Grape phylloxera (Daktulosphaira vitifoliae Fitch) is a historical pest of grapevine with worldwide economic and ecological importance. Phylloxera is native to the eastern United States of America where its natural hosts are American Vitis species. These natural hosts show varying levels of resistance to the insect and a few accessions of Vitis spp. have been used to produce rootstocks for use in commercial viticulture worldwide. The use of such rootstocks is, to‐date, the only means by which economically viable grape production can be reliably maintained from Vitis vinifera in a phylloxera‐infested vineyard. If the recent release of the grape genome has accelerated rootstock breeding programmes, the long‐term stability of the host‐plant resistance is conditioned to the non emergence of virulent phylloxera strains. However, there has been recent evidence in Australia of the emergence of two apparently resistant phylloxera clones, which suggests that previously host‐resistant plants can now be susceptible to phylloxera. In contrast with the accurate and detailed historic studies on the biology of this insect, genetic information is still quite limited on this potentially dangerous species for a major crop.

We propose the sequencing of the phylloxera (Daktulosphaira vitifoliae Fitch) genome through an integrated approach. Phylloxera, because of its basal phylogenetic relationship to aphids, provides an interesting model for comparative genomics between aphids (in the broad sense). The phylloxera sequence will also fill the gap between aphids and related taxa such as bugs, cicadas and leafhoppers, psyllids and whiteflies. Knowledge of the genome of the phylloxera will considerably improve our understanding of many of the specific biological features of this invasive pest. This include identifying genes for complex traits including those with relevance to the genetic basis of host‐plant interaction, to leaf gall and root formation, to nutrition on grape, and to the developmental causes of extreme phenotypic plasticity. Finally, knowledge of the phylloxera genome is also relevant to human and economic well being by participating to reduce environmental cost and risk in viticulture.