Evaluation of Transgenes in Floral Crops for Arthropod Resistance
Some of the most successful plants on the planet boast potent,
built-in, chemical defenses against bugs. Coffee and tea plants’ caffeine,
some mums’ pyrethrum, and tannic acids in acorns and tree bark naturally
discourage insect pests. And these bug repellents and insecticides are
just a sampling of Mother Nature’s chemical-control cache. Now, advances
in the genetic engineering of plants are allowing researchers the opportunity
to splice one plant’s bug resistance into another. In a series of cutting-edge,
Endowment-assisted studies begun in 1994, entomologist Dr. John Sanderson
has been screening promising plant genes responsible for giving bug-zapping
plants their special defense capabilities. In an early focus on whitefly
control, Sanderson slipped a gene (TdC) producing tryptamine (which is
acutely toxic to whiteflies) into petunia and poinsettia plants. The gene
worked well in protecting petunias. But in poinsettias, the chemical’s
concentrations remained too low to function as a defense.
Sanderson has since moved on to trialing the tryptamine gene
in other plants on other key pests.
Spider mites, which have managed to outmaneuver most genetic engineers,
show distaste for tryptamine in Sanderson’s studies. As do green-peach
aphids. So far, adult thrips seem unconcerned about the chemical. Sanderson
is now scheduling lunch dates for fresh batches of the same insects with
tryptamine-transformed chrysanthemums, geraniums, lisianthuses, New Guinea
impatiens, roses, vincas, and other crops. And he’s pushing forward with
confidence as he writes, “Once effective genes are discovered and plant
regeneration techniques developed, it is conceivable that these genes may
be inserted into any number of crop species and cultivars.” As the entomologist
continues to successfully package potent insect toxins in pretty plants,
Endowment members will be the first to know.
FOR MORE INFORMATION, CONTACT RESEARCH-PROJECT LEADER:
Dr. John Sanderson, Associate Professor of Entomology, Cornell University
E-MAIL: <jps3@cornell.edu>
