How crops are being disaster-proofed

Late blight is an old foe of humans. This disease catalysed the devastating Irish potato famine that began in 1845.

It is caused by a fungus-like pathogen, which quickly kills a potato plant and turns the crop into inedible mush.

More recently, late blight has been creeping into higher parts of the Peruvian Andes, as warmer, wetter weather helps the pathogen spread.

So scientists at the International Potato Center (CIP), a research institute in Peru, were very motivated to develop potato varieties that could resist late blight.

They searched for this trait among so-called crop wild relatives – undomesticated plants that are distantly related to the ones now grown for food.

After finding the disease resistance in potato wild relatives, they crossed the wild plants with cultivated ones. Local farmers then tested the newly developed varieties, voting for the ones they preferred to grow, sell and eat.

The result is CIP-Matilde, a potato variety released in 2021 that doesn’t require fungicides to stand up to late blight.

“Usually it’s easier to improve the resistance to a certain disease,” explains Benjamin Kilian, a senior scientist at the Crop Trust, based in Bonn, Germany. The non-profit organisation partnered with CIP to develop the Matilde potato, and is working on many other crop varieties.

While disease resistance might come down to a single gene, making resistance to stressors like drought or salinity, can involve working with hundreds of genes.

To tackle drought tolerance, for instance, scientists could explore traits like early flowering to escape the effects of drought, less loss of water from plant leaves, or long roots so that plants can extend further to reach water…

Traditional crop breeding can be time-consuming and laborious. Brad Ringeisen, the executive director of the Innovative Genomics Institute (IGI) at the University of California (Berkeley and San Francisco), believes that gene editing using tools like Crispr-Cas9 is the most impactful way of ensuring that crops can withstand disasters.

“It speeds up the innovation cycles. It is a precise tool.”

Mr Ringeisen summarises the IGI’s work on disease resistance in crops: “There are a tremendous number of emerging diseases, and climate change is not helping this.”

He says gene editing is a more elegant way of tackling disease than spraying more pesticides.

As well as disease resistance, the IGI is working on drought tolerance. A rice variety that has been gene edited to reduce the number of pores on leaves, reducing water loss, is now in field trials in Colombia. Such tests are necessary to make sure that gene edits don’t lead to unforeseen side effects in practice.

The IGI’s project is one of a number of scientific efforts to make rice less vulnerable to unpredictable water cycles. Scientists at the International Rice Research Institute in the Philippines, for example, have developed a “scuba rice” strain that can withstand weeks of submergence in water during floods…







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