Agronomist urges farmers to be cautious after researchers in China developed gene-edited wheat that they say is impervious to powdery mildew, a disease caused by a fungus that attacks the plant and forms a white powdery spore on new tender growth then spreads out into other plant parts.

A team of experts at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences led by Gao Caixia used gene-editing methods to create the same protective mutation in six copies of the Mildew Locus O (MLO) genes in wheat.

According to a peer-reviewed study published in journal Nature, the scientists made targeted changes to a genome. “I was sure that we had discovered something amazing,” Ms Gao says after her gene-edited plants resisted infection by powdery mildew.

The plant also grew just as well as unmodified control plants in greenhouse experiments.

Ms Gao said that while examining the genome of the modified plants, they found that the editing had accidentally removed not only part of an MLO gene but also a large stretch of DNA on one chromosome. The result was that a nearby gene called TMT3 became more active and this is what keeps the plant growth normal.

The team say the approach may work in other crops such as strawberries and cucumbers.

Crop makeup

However, Emmanuel Atamba, a Kenyan agronomist and food security expert, urged caution when it comes to adopting gene-edited crops.

“Powdery mildew is common because most of the fungi in the soil multiplies vegetatively. Using gene editing to deal with it is an exaggerated attempt and I have concerns about the safety,” he said.

“We shouldn’t be so excited because scientists can make errors. We should not be open to changing the genetic make-up of a crop. We should instead think of solving the issue without risking because gene-editing is done in the embryo,” he said.

He advocated simple and time-tested techniques to deal with powdery mildew.

“Good aeration on the crops works effectively. It’s simply a matter of balancing moisture and observing hygiene. We have a problem with pesticides and their use here but we shouldn’t rush to gene-editing because of the risk it poses and can harm the environment,” Mr Atamba said.