Molecular biology shows route to new crops
By Helen McMenamin
The short season and delicate crops that provide decent returns for farmers in gentler climates may soon be viable options for the prairies.
Prairie weather, with its short growing season, hot summers, droughts and early
frosts, takes the shine off many potentially profitable crops and adds risk
to crops that can be grown, especially beans and potatoes. Larry Gusta may have
the answer. His team at the Crop Development Centre in Saskatoon has isolated
a stress tolerance gene from brome grass that enables the grass to survive and
thrive through all sorts of weather challenges.
Gusta was trying to find how brome grass survives frost, drought, salinity
and other types of stress. He analyzed the protein make-up of the plants growing
under normal conditions and when they were subjected to stress, like drought,
heat and frost.
The stressed plants all had high levels of a protein that was not present in
those grown in good conditions. "We tried for years to isolate that protein,"
he says. "But, it was like tracking a ghost."
Eventually, Gusta used a tissue culture of brome grass cells that he could
subject directly to stresses like saline media and cold or heat. He was able
to isolate the protein and link it to a universal stress gene.
Thanks to the gene libraries and new gene sequencing technology, Gusta was
able to clone the gene, which is turned on and produces the stress protein under
stressful growing conditions. His team has now inserted copies of that gene
into canola, flax and potato.
"Those crops are relatively easy to transform (genetically modify),"
says Gusta. "We're using canola for field trials because genetically modified
canolas are already being widely grown. And, we've had wonderful results. The
transformation has made a spectacular difference to those crops. In some cases,
it speeded up development by two weeks. That sort of improvement would make
soybeans a viable crop for the prairies."
Crops with the stress gene gained a great advantage over conventional crops
by growing quickly and vigorously early in the season. That made all the difference
when there was an early frost.
"When we harvested the untransformed canola there was nothing there,"
says Gusta. "The canola with the stress gene inserted was perfect because
it was already mature when the frost hit. The seed would have graded Number
Potatoes were able to grow rapidly at four degrees C and withstand temperatures
of minus four degrees C with no damage.
Gusta believes developments like hardier crops are essential if western Canada
is going to compete in global markets. "Crop breeding has improved our
crops," he says. "But the big increases in production have come from
increased use of inputs like fertilizer and herbicides. As nitrogen costs increase,
worldwide phosphorus supplies decrease and the climate becomes hotter and drier,
the risks in crop production are increasing. We need crops that yield well when
conditions are less than ideal. This gene may provide that.
"The universal stress gene we've patented, ROB 5, may enable us to develop
crops with enhanced heat, drought and freezing tolerance. So far, we've seen
germination increased by as much as 80 percent, earlier, more uniform emergence
and maturity, and yields up to 60 percent higher. In the case of potato, even
the cooking quality improved."
Opposition to GMOs will not eliminate the benefits of Gusta's work. "We're
discovering the pathways plants use to compensate for stress," he says.
"Once we know what's going on in the cells, we can predict what this particular
gene will do. We'll have shown what can be done. Once we prove what's possible
through genetic transformation, breeders can set new goals and use genetic modification
or traditional methods to include a universal stress gene in their new varieties,"
"We're on the road to understanding how the systems work, how we can achieve
faster germination and frost, heat and drought tolerance." -30-
The Bottom Line
What do you mean, 'worldwide phosphorus supplies are decreasing'? We will also
need a gene that enables a plant to fix its own phosphorus!
Huvenaars, Hays, Alberta.