Sunday, December 21, 2014
YOLO COUNTY NEWS
99 CENTS

Insects direct diversity through plant defenses

By
From page A4 | October 28, 2012 |

As restaurant patrons’ diverse food preferences give rise to varied menu offerings, so plant-eating insects’ preferences play an important role in maintaining and shaping the genetic variation of their host plants in a geographic area, reports an international team of researchers that includes a UC Davis plant scientist.

The new study, involving aphids and the broccoli-like research plant Arabidopsis thaliana, provides the first measureable evidence that this selective process is driven, in part, by the pressure that multiple natural enemies exert on plants by forcing them to create diverse natural defenses to avoid being eaten.

Findings from the study, conducted with researchers in Switzerland, Denmark and England, appear in the Oct. 5 issue of the journal Science.

“Our data demonstrate that there is a link between the abundance of two types of aphids and the continental distribution of Arabidopsis plants that are genetically different in terms of the biochemicals they produce to defend against insect feeding,” said UC Davis plant scientist Dan Kliebenstein.

His laboratory is examining the naturally occurring chemicals involved with plant defenses to better to understand their role in the environment and to explore their potential for improving human nutrition and fighting cancer.

Ecologists have theorized for decades that genetic change and variation within a plant or animal species is critical to enabling the species to survive such changing environmental conditions as the appearance of a new disease or pest.

They have documented that nonbiological changes, such as variations in climate and soil, can exert pressures that cause genetic variation within plant species. However there has been little evidence that biological forces, including insects feeding on plants or competition between plant species, can lead to genetic variation within a plant species across a large geographic area.

In the new study, the researchers first mapped the distribution of six different chemical profiles within Arabidopsis thaliana plants across Europe, each chemical profile controlled by the variation in three genes.

The mapping revealed a change in the function of one of these key genes across geographic areas; the gene changed from southwest to the northeast.

The researchers theorized that two aphid species — Brevicoryne brassicae and Lipaphis erysimi — were the likely causes of the geographic variation. Both are abundant in the regions and feed heavily on Arabidopsis and related plants.

The scientists then tapped data collected by British researchers for nearly 50 years on fluctuations in aphid populations in Europe. They found that distribution of the two aphids species of interest closely mirrored the geographic distribution of the different chemical types of Arabidopsis plants. One aphid preferred the southwestern chemical type while the other aphid preferred the northeastern chemical type.

The next step was to determine whether the similarity between the distribution patterns of the plants and the two aphid species was more than coincidental. To do this, the researchers observed what happened when the different aphids fed on five generations of experimentally raised Arabidopsis thaliana plants.

They confirmed that the plants were genetically adapting to the aphids, with each successive plant generation showing less damage from the feeding insects. A change in the genetic makeup of the plant populations specific to each aphid accompanied this trend — and the laboratory plants evolved in a way that tracked the geographic distribution of the two aphids and the plant chemical types.

The researchers also found that when faced with feeding by aphids, the faster-growing Arabidopsis plant types fared better in the laboratory, while the slowest-growing plant types actually went experimentally extinct.

“These data make it clear that even functionally similar plant-eating pests can affect the biochemical and genetic makeup of plant populations, playing a major role in shaping and refining the plant defenses in a natural community,” Kliebenstein said.

The study was led by Tobias Züst of the University of Zürich.

— UC Davis News Service

Comments

comments

  • Recent Posts

  • Enter your email address to subscribe to this newspaper and receive notifications of new articles by email.

  • .

    News

     
    What’s new at UCD? Construction projects abound

    By Tanya Perez | From Page: A1 | Gallery

    No-nonsense Musser voted Citizen of the Year

    By Dave Ryan | From Page: A1 | Gallery

     
    Sharing a meal, and so much more

    By Anne Ternus-Bellamy | From Page: A1 | Gallery

    Brinley Plaque honors environmental stalwart

    By Dave Ryan | From Page: A1 | Gallery

     
    Raul Castro: Don’t expect detente to change Cuban system

    By The Associated Press | From Page: A2

    Police seek help in finding runaway twin girls

    By Enterprise staff | From Page: A2

     
    Downtown crash results in DUI arrest

    By Lauren Keene | From Page: A2

    March trial date set in Davis molest case

    By Lauren Keene | From Page: A2

     
    North Korea proposes joint probe over Sony hacking

    By The Associated Press | From Page: A2

     
    AP sources: Cops’ killer angry over Garner death

    By The Associated Press | From Page: A2

     
    Luminaria display planned in West Davis

    By Enterprise staff | From Page: A3

    Soup’s On will benefit NAMI-Yolo

    By Enterprise staff | From Page: A3

     
    Pedal around Davis on weekly bike ride

    By Enterprise staff | From Page: A3

     
    Supplies collected for victims of abuse

    By Enterprise staff | From Page: A3

    Donors, volunteers honored on Philanthropy Day

    By Special to The Enterprise | From Page: A3 | Gallery

     
    Enterprise plans Christmas, New Year’s holiday hours

    By Enterprise staff | From Page: A3

     
    Surprise honor is really nice, dude

    By Enterprise staff | From Page: A5 | Gallery

     
    Konditorei presents free holiday concert

    By Enterprise staff | From Page: A5

    .

    Forum

    E-cigs surpass regular cigarettes among teens

    By The Associated Press | From Page: B4

     
    It’s not a pretty picture

    By Creators Syndicate | From Page: B4

    Google me this: Should I hit that button?

    By Marion Franck | From Page: B4

     
    Too late to pick a fight

    By Creators Syndicate | From Page: B5

     
    All police need to humanize

    By Letters to the Editor | From Page: A10

    Are we only a fair-weather bike city?

    By Letters to the Editor | From Page: A10

     
    Join us in making our world more just

    By Special to The Enterprise | From Page: A10

     
    Tom Meyer cartoon

    By Debbie Davis | From Page: A10

    The electronic equivalent of war

    By Special to The Enterprise | From Page: A11

     
    The Green House effect: Homes where the elderly thrive

    By New York Times News Service | From Page: A11

    .

    Sports

     
    Stenz shines as DHS girls take a tournament title

    By Enterprise staff | From Page: B1 | Gallery

    Aggie Manzanares not quite finished carrying the rock

    By Bruce Gallaudet | From Page: B1 | Gallery

     
    UCD women look to improve, despite game at No. 7 Stanford

    By Bruce Gallaudet | From Page: B1 | Gallery

    Second-half run spurs Aggie men to 8-1

    By Enterprise staff | From Page: B1

     
    49ers fall to San Diego in overtime

    By The Associated Press | From Page: B10

    .

    Features

    .

    Arts

    .

    Business

    Marrone Bio expands its product reach in Latin America

    By Enterprise staff | From Page: A4

     
    Sierra Northern Railway names CEO

    By Special to The Enterprise | From Page: A4

    Sink your teeth into Vampire Penguin

    By Wendy Weitzel | From Page: A4 | Gallery

     
    .

    Obituaries

    .

    Comics

    Comics: Sunday, December 21, 2014

    By Creator | From Page: B8