Crop Tech Corner

ST. LOUIS (DTN) -- This bi-monthly column condenses the latest news in the field of crop technology, research and products.

SWEET POTATOES PROVE A "NATURAL" GMO

The humble sweet potato could turn the debate over genetically engineered (GE) food on its head. Scientists from the University of Ghent and the International Potato Center made a startling discovery while perusing the spud's genome for viral diseases. It turns out sweet potatoes from all over the world are harboring genes from Agrobacterium, the soil bacterium whose gene transmission abilities have made it a favored method for genetically engineering crops by inserting new genes into them. These "foreign" bits of DNA were found in all of the 291 sweet potato cultivars examined, which "suggest that an Agrobacterium infection occurred in evolutionary times," the scientists concluded.

Importantly, the same genes were found in only a fraction of various wild relatives of the sweet potatoes examined in the study. This disparity suggests that the Agrobacterium genes were selected for during traditional domestication of the spuds -- long before the era of genetic engineering -- because they produced favorable traits. In their study, the scientists expressed hope that this discovery could change the common public perception of genetically engineered food as unnatural and unsafe. "Our finding, that sweet potato is naturally transgenic while being a widely and traditionally consumed food crop, could affect the current consumer distrust of the safety of transgenic food crops," they concluded.

You can find the scientists' newly published study here: http://bit.ly/… and a summary of it in the Crop Biotech Update here: http://bit.ly/….

NEW BT PROTEIN PROVES SAFE

The beetles and weevils of the world could soon face another Bt weapon in the fields. South American scientists have been eyeing Cry8Ka5, a mutant Bacillus thuringiensis (Bt) protein. The protein shows good activity against the coleopteran class of insects, which includes the troublesome boll weevil, a major pest for Brazilian cotton growers. Now the protein has passed a food safety assessment by a group of South American researchers. The scientists examined Cry8Ka5 for similarities to allergenic proteins, toxic effects or "antinutritional" proteins. For a control, they selected Cry1Ac, a widely used Bt protein that has already been proven safe for consumption. After passing tests in mice and simulated gastric fluid, "no expected relevant risks are associated with the consumption of Cry8Ka5 protein," the scientists concluded in their recently published study.

You can find the study here: http://bit.ly/….

AFRICANS WORK ON AFLATOXIN-RESISTANT CORN

Kenyan scientists are using a biotech genetic technique called "host-induced gene silencing" to produce corn plants that resist the accumulation of aflatoxins, a dangerous group of toxins produced by the Aspergillus fungus. African farmers have been unsuccessful in controlling the fungus, and many sub-Saharan communities that rely on corn for food have been increasingly exposed to the toxin, the scientists noted in their study. Using the gene-silencing technique, the researchers managed to produce transgenic corn plants that showed a 14-fold decrease in aflatoxin levels after being exposed to a strain of Aspergillus fungus common to eastern Kenya.

Unfortunately, the effort wasn't a solid win. The transgenic corn ears also showed some stunting and fewer kernels. The researchers believe this may be the result of "'off-target' silencing of unintended genes." However, they remained optimistic, and concluded that the host-induced gene-silencing technique "holds great potential for developing aflatoxin-resistant plant germplasm for the African context where farmers are unable to make further investments other than access to the germplasm."

You can find the study here: http://bit.ly/….

Emily Unglesbee can be reached at emily.unglesbee@dtn.com

Follow Emily Unglesbee on Twitter @Emily_Unglesbee

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