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New plant genes improve crop stress tolerance and yields

Environmental stresses cause the greatest degree of unpredictability in crop production.


March 17, 2009
By Donna Fleury

Environmental stresses cause the greatest degree of unpredictability in crop production. Even the best management strategies and farming systems can be compromised when frost, drought or other stresses occur during the growing season.

Slide1 
 The effect of Rob-5 on seedling vigour.
 Photo courtesy of Dr. Larry Gusta, University of Saskatchewan.
 

“Big companies have identified abiotic stress as the number one driver right now for them to put into seed for increased yield,” explains Dr. Larry Gusta, professor emeritus at the University of Saskatchewan. The term ”abiotic stress” covers a variety of factors that can cause harmful effects to plants such as soil conditions, drought or extreme temperatures. “Farmers would pay additional money for seed genetics that will improve crop yields and profitability, and reduce the risk of abiotic stress factors during the growing season.”

Gusta and his research team have patented a new plant gene, called Rob-5 that improves environmental stress tolerance, increases plant vigour and seed yield, and shortens the time required for plants to mature. One of the world’s leading crop science companies has licensed the Rob-5 gene from the University of Saskatchewan in order to explore its commercialization possibilities. “This new plant gene was discovered in brome grass and represents a novel class of plant genes,” explains Gusta. “Transgenic plants expressing Rob-5 can show a dramatic improvement in their capacity to tolerate a variety of stress conditions, such as frost, drought and heat.”

Along with enhanced stress tolerance, the plants with the Rob-5 gene had an increased germination rate and seedling vigour, faster emergence, earlier establishment, fewer days to flower and shortened maturity. “The canola crops with the Rob-5 gene on average, flowered two weeks earlier and matured anywhere from 10 to 14 days earlier than other crops,” says Gusta. “In one year, an early August frost damaged most of the canola crops resulting in almost complete yield losses. However the Rob-5 canola plants were fully mature and did not show any frost damage or yield losses.” These crops also showed a 35 percent yield advantage.

Slide2 
The effect of Rob-5 on days to flowering and maturity.
Photo courtesy of Dr. Larry Gusta, University of Saskatchewan.

 

Gusta and his research team are using various tools, such as genomics, proteomics, bioinformatics and other methods to find more Rob-5 look alike genes. “We believe there are better ones out there, and we also want to take genes like Rob-5 and combine them to make super genes and enhance their activity.”
Gusta is working with more than 100 genes and several proteins, metabolites and hormones associated with abiotic stress factors, such as low temperature, frost, heat, drought and salinity. “We’re also looking at genes associated with germination and seed vigour,” explains Gusta.  In some years, growers have to reseed due to early spring frosts and losses of early seeded crops, losing several hundred dollars per acre of inputs. This can also delay maturity, creating potential problems at harvest.  “We’re looking for something that would withstand two or three degrees C of frost, which would not only save farmers money from reseeding, but also reduce days to maturity and fall harvest risks.” Gusta has launched a new large project focused on genomics of abiotic stress, including identifying genes involved in freezing. “Although not well understood, in order for water to freeze close to zero it has to have something called a nucleator to initiate the formation of ice, otherwise it is what we call super-cooling.” For example, water can be super-cooled down to -100 degrees C and still remain liquid.

Gusta has some evidence to indicate that plants have certain genes that produce proteins that act as a nucleator, causing them to freeze. “We want to identify these genes, knock them out and silence them,” explains Gusta. “Hopefully we can have plants super-cooled to -7 to -9 degrees C and they will escape any frost damage. Without frost, there is no injury to the plants from cooling.” Gusta has cooled some canola plants in the growth chamber down to -12 degrees C and they did not freeze. However, there are other dynamics involved that complicate the process.

In the future, Gusta hopes these new genes will protect the plant during the whole growing season, not only field crops but also flowering fruit trees and other crops around the world. “With global warming, we’re going to see higher temperatures and drier conditions, and increased abiotic stresses to crop production,” says Gusta. “Over the next few years, we expect to have several Rob-5 look-alikes and other genes available for commercial partners to include in their seed genetic development to protect against abiotic stress.”
Ultimately it will provide sustainability to crop production, and farmers will have some insurance they can produce a better crop with less risks.

Biomass crop technology
With the rising interest in biofuels and other bioproducts, researchers are also looking for improved crop traits in crops designed specifically for biomass production. Performance Plants Inc. (PPI), a leading Canadian food and biofuel biotechnology company has developed patented crop technology that will benefit growers and end users of biomass crops. PPI has research centres in Kingston, Ontario and Waterloo, New York focussing specifically on biomass crops, and another centre in Saskatoon, Saskatchewan focussed on food crops.

“PPI’s capacity to deliver innovative products for the biofuels industry is now totally in-house, from trait discovery to registered crop seeds for farmers and biomass feedstock for industry,” says Peter Matthewman, president of Performance Plants Inc. “Our focus is on developing traits that enable plants to withstand the changing global environmental and climatic conditions. We are developing non-food biomass feedstocks that will be grown on land and under conditions less suitable for food or feed production. Although the crops might look the same, the traits can be optimized to meet end-user processing specifications.”

PPI developed a genetic trait technology ideal for plant biomass applications such as cellulosic ethanol, fibre and forage. “Our Biomass Enhancement Technology (BET) delivers twice the biomass yield by dramatically boosting vegetative plant growth,” says Matthewman. “Increased cellulose per acre significantly reduces feedstock costs per ton, a key requirement of the ethanol industry.” Some biomass energy crops have been trialled including switchgrass, miscanthus grass, sorghum, big bluestem and tropical corn.

Dedicated plants designed to provide optimum conversion of cellulose into ethanol or other biofuels also have been developed. Matthewman explains the problem with current cellulosic ethanol production today is the huge upfront processing cost associated with the biomass before it can go into the fermentation process. PPI has developed a unique cellulose wall digestibility trait, called Enhanced Convertibility Trait (EC) that increases ethanol yield and reduces the need for intensive pre-processing.

PPI also has developed a suite of patented weatherproof technologies for both food and biomass crops. The Yield Protection Technology (YPT) enables plants to withstand the debilitating effects of drought and is anticipated to be available in corn by 2011. The Heat Tolerance Technology (HEAT) trait allows plants to withstand yield losses due to heat stress, and the Water Efficiency Technology (WET) allows crops to produce the same yields with up to 25 percent less water. These traits will produce consistent high seed or biomass yields each year.

Getting through the necessary research, development and regulatory aspects for new biofuel crops requires a seven to eight year development program. Matthewman hopes to see the first commercial non-food crops available by 2013, and expects to have a range of varieties suited to the various cropping areas across Canada. Technology traits are also being investigated for renewable biochemical and bioproduct crops for the future. Matthewman adds, “agriculture technology and the agriculture industry are going to be fundamental in dealing with the future issues of fuel, food and the environment."