Media Releases

Discovery offers hope of saving sub-Saharan crops from devastating parasites

September 10, 2010

TORONTO, ON – Each year, thou­sands of acres of crops are plant­ed through­out Africa, Asia and Aus­tralia only to be laid to waste by a par­a­sitic plant called Stri­ga, also known as witch­weed.  It is one of the largest chal­lenges to food secu­ri­ty in Africa, and a team of sci­en­tists led by researchers from the Uni­ver­si­ty of Toron­to have dis­cov­ered chem­i­cals and genes that may break Striga’s stran­gle­hold.

When crops grow, their roots release a plant hor­mone called strigo­lac­tone. If the soil con­tains Stri­ga seed, it will use the released strigo­lac­tone as a cue to ger­mi­nate and infect the crop plants. Once con­nect­ed to the crop, the Stri­ga plant kills the crop by suck­ing out its nutri­ents. “In sub-Saha­ran Africa alone, Stri­ga has infect­ed up to two-thirds of the arable land,” says U of T cell and sys­tems biol­o­gist Peter McCourt, prin­ci­ple inves­ti­ga­tor of a study pub­lished this week in Nature Chem­i­cal Biol­o­gy.  “With chem­i­cals and genes in hand that influ­ence strigo­lac­tone pro­duc­tion in plants, we should be able to manip­u­late the lev­el of this com­pound by chem­i­cal appli­ca­tion or plant breed­ing which would break the Stri­ga-crop inter­ac­tion.

The sci­en­tists used a mod­el genet­ic plant sys­tem called Ara­bidop­sis to screen 10,000 com­pounds and iden­ti­fy a set of five chem­i­cals, des­ig­nat­ed cotylim­ides, which increase the accu­mu­la­tion of strigo­lac­tone in plants.  They also found relat­ed chem­i­cals that decrease strigo­lac­tone lev­els.  From there, they screened for mutants of Ara­bidop­sis that were resis­tant to cotylim­ides and iden­ti­fied mutants that made less strigo­lac­tone.  These mutants iden­ti­fied genes that reg­u­late strigo­lac­tone lev­els in plants.

The research team includes mem­bers from the Uni­ver­si­ty of Toronto’s Depart­ment of Cell and Sys­tems Biol­o­gy and Cen­tre for Analy­sis of Genome Evo­lu­tion and Func­tion, as well as the RIKEN Plant Sci­ence Cen­ter in Yoka­hama, Japan.


For more infor­ma­tion, please con­tact:

Peter McCourt
Depart­ment of Cell & Sys­tems Biol­o­gy
Uni­ver­si­ty of Toron­to
647–308-1236 (cell)

Kim Luke
Depart­ment of Com­mu­ni­ca­tions, Fac­ul­ty of Arts & Sci­ence
Uni­ver­si­ty of Toron­to