USDA researcher developing headblight-resistant GMO barley

A USDA researcher in southeast Idaho is developing a genetically modified barley line that will tap into natural plant processes to ward off the fungal disease Fusarium headblight.

Phil Bregitzer, a research geneticist with the USDA's Agricultural Research Service in Aberdeen, Idaho, said he's also found a way to manipulate plant genes to help him remove all traces of the remaining "garbage" used to introduce foreign traits.

Bregitzer, who received a $20,000 grant for the project in June from the U.S. Wheat and Barley Scab Initiative, believes he could have a transgenic barley line developed within two years. If a line goes forward, approval could take several more years.

Fusarium headblight has hurt barley industries further east and is surfacing in Idaho wheat, though it hasn't posed a problem yet for the state's barley growers. The disease hurts plant yields and also creates the DON toxin, which is harmful for health.

Bregitzer said his technology would also be transferable to wheat.

"The traditional plant breeding approach is slowly yielding improvements, but when you're talking about something you want zero of, less of a lot, or even half of a lot, can be unacceptable," Bregitzer said. "We can't do it as quickly as we would like in the traditional way."

Bregitzer believes GMO technology is safe, but acknowleges perception can affect trade. Any GMO material eventually produced in his field trials will be destroyed.
For the project, Bregitzer will introduce a gene to create double-stranded RNA within barley. RNA is the gene's encoded message. The plant's natural defenses will break apart the RNA, leaving the segments to seek and destroy their mirror images in the RNA of invading headblight fungi.

Bregitzer will insert his genes into movable segments of DNA, called transposons, isolated from corn. The tansposons will move his transgenic traits to different chromosomes from the bacterial backbone and genetic markers used to introduce them. This leftover "garbage" can be removed in progeny through the normal breeding process.

Bregitzer believes the project will further knowledge about the barley genome and the interaction between the fungus and the plant, providing insight that could be useful in field management and conventional breeding.

University of Idaho Extension cereals pathologist Juliet Marshall said there's been a shift toward the headblight species Fusarium graminearum, which thrives on corn, as Idaho corn production has increased to supply dairies. She said DON toxin levels have been detected at 4-7 parts per million in wheat fields north of Idaho Falls. Exceeding 5 parts per million is considered grounds for rejection in wheat. Malting barley, which is somewhat less susceptible to headblight due to the way in which it flowers, can be rejected at levels between 0.5 and 1 parts per million.

Once Bregitzer commences field trials, Marshall will help evaluate DON toxin levels and headblight control.

"It's a beautiful project -- a great tool potentially to develop resistance to a fungus we really have no conventional method of developing resistance to as of yet," Marshall said.

For the time being, Marshall recommends wheat growers use fungicides at flowering and plant conventionally bred wheat varieties with the best headblight resistance, such as UI Stone, following corn.