Rice and maize yields boosted up to 10 per cent by CRISPR gene editing

Turning off a particular gene in maize and rice could enhance grain yields by 10 per cent and 8 per cent respectively, according to a new study. By exploring similar genes in other cereal grains, global crop production could be boosted.

Maize and rice are staple foods around the world, and each has a distinct history of cultivation for large-scale consumption. It is believed that maize originated in Mexico, while rice came from China. Despite the independent evolution of these species, plant biologists have noted that they possess some very similar traits. This is known as convergent evolution.

To investigate these resemblances, Xiaohong Yang at China Agricultural University in Beijing and her colleagues mapped the genomes of maize (Zea mays L. ssp. mays) and rice (Oryza sativa).

They found 490 pairs of genes that seemed to serve analogous functions in both grains. From these pairs, the researchers identified two genes – known as KRN2 in maize and OsKRN2 in rice – that affected their grain yield. By using CRISPR gene editing to switch off these genes, they could increase grain yield by 10 per cent in maize and 8 per cent in rice. These figures came from real-world tests in farm fields.

“These are excellent results,” says Yang, who hopes to continue exploring the 490 gene pairs to further improve rice and maize production.

“These are two species that are the most important in terms of the economy,” says co-author Alisdair Fernie at the Max Planck Institute of Molecular Plant Physiology in Potsdam, Germany. “They have such different domestication histories with different centres of origin, and very different habitats to a large extent. The fact that convergent evolution happened with so many genes is fascinating.”

A better understanding of the genetic evolution of maize and rice could also lead to what are known as de novo domestication events, says Fernie, which is when domesticated genes are inserted into non-domesticated species to make new crops. Wild crops are generally more resilient against extreme weather and pathogens, but typically have a low yield.

“With CRISPR and gene editing, we could just take a handful of these domestication genes, such as KRN2, and introduce them back into their wild species relative,” he says. “The idea is that you could make high-yielding but resilient crops, which will be critical for us in the future.”

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