story to find out more.
Samuels views endophytic Trichoderma species through a microscope. The
endophytes can be seen on the screen in the background. Click the image for
more information about it.
Cocoa Plants Find a Friend in Fungi
By Erin Peabody
June 7, 2006
It's a sweet deal. Cacao treesNature's chocolate
sourceoffer certain fungi a place to live and hang out. In return, the
tiny tenants stand guard, ready to protect their plant-based homes from
That's the finding of scientists with the Agricultural Research
Service (ARS) and their colleagues, who
are looking for ways to protect Theobroma cacao, known as cacao, from
destructive pathogens that can ruin the plant's cherished crop of cocoa beans.
In Latin America, where about one-third of the world's chocolate
originates, the two most persistent cocoa spoilers are witches' broom and
frosty pod rot. Right now, chemical fungicides are farmers' best defense
against the diseases.
But experts at the ARS
Botany and Mycology Laboratory in Beltsville, Md., and their collaborators
have an all-natural alternative in mind. They've found that certain fungal
endophytes, which take up residence in plants, make ideal roommates capable of
keeping disease-causing microbes at bay.
Endophytes are fungi or bacteria that live within the nooks and
crannies of living plants and trees but cause no apparent harm to their hosts.
These live-in microorganisms set up shop pretty much wherever they want: in a
tree's leaves, stems or trunk.
Samuels, a mycologist at the ARS Beltsville laboratory, is part of a team
of experts who are traveling the globe in search of new and promising
endophytes. He named and described one recent discovery: Trichoderma
ovalisporum. Samuels' colleagues, including Harry Evans with
CABI Bioscience in the United
Kingdom, found the fungus growing inside a tropical woody vine in Ecuador.
Laboratory and field studies show that this endophyte is effective at
running off the frosty pod rot pathogen. If it continues to prove its worth,
T. ovalisporum's spores could someday be applied to cacao tree flowers
to help shield the plantand its precious beansfrom fungal attack.
about the research in the June 2006 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.