Understanding (and Destroying) Grape Phylloxera

Pylloxera galls on grape leaf

This leaf is riddled with galls, a symptom of grape phylloxera pressure. Photo by Whitney Cranshaw

Genome mapping may benefit growers in their fight against grape phylloxera (Daktulosphaira vitifoliae), the insect that infested Pacific Northwest vineyards last year.

Researchers at the University of California, Riverside, after a decade of study, have mapped out the genome of the aphid-like pest, which is capable of decimating vineyards. Phylloxera causes grapevines to lose their leaves and, if the infestation reaches the roots, plants could die.

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In discovering how phylloxera spreads, scientists potentially know how to stop it as well by engineering phylloxera-resistant grapevines.

“Growers currently have to graft roots to make their plants viable,” Paul Nabity, an Assistant Professor of Plant-Insect Ecology at UC Riverside, said. “A lot of money and effort could be saved with pest-resistant rootstocks.”

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Native North American grapevines co-evolved with phylloxera and are now resistant to the pest. However, most of the grapes consumed in the U.S. are European varieties. As a result, growers have to graft North American roots onto their European grapevines to give them tolerance to the insect.

The researchers, in work that was recently published in a BMC Biology paper, identified nearly 3,000 genes that enable phylloxera to colonize and feed on grape vines while creating what are essentially nutritionally enhanced tumors. The insects live in and feed off these structures, which also protect them from attack by other parasites.

“In effect, phylloxera creates its own refrigerator on the plant that it can feed from whenever it wants,” Nabity said.

The tumor-like structures, known as galls, disrupt the vine’s ability to move nutrients and feed itself. They also create wounds in roots that make grapevines more susceptible to fungi and other pathogens, ultimately killing the vines.

Claude Rispe, with the French National Institute for Agriculture, Food, and Environment, led the research team. Nabity helped identify how phylloxera secrete molecules that can change the immune system of grapevines.

“These molecules alter the plant’s defense systems and make it so that the plant doesn’t know it’s being attacked,” Nabity said.

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Avatar for tem2atcornelledu tem2atcornelledu says:

Foliar phylloxera (photo) isn’t an issue with V. vinifera vines, and rootstocks (or rootstock breeding) doesn’t help with the foliar phylloxera – that has to do with genetics of the scion. Would like to see more features about grape breeding, including the vitisgen2 project – nationwide, but hosted at Cornell AgriTech.
Regards, Tim Martinson

Avatar for Andrea Tremblay Andrea Tremblay says:

so what are you supposed to do about this??

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