Crispr-Edited Bananas Get Industry Funding

Cavendish bananas resistant to TR4 grown in Australia (Queensland University of Technology)

18 Feb. 2021. A popular type of banana, genetically edited to resist a soil fungus that threatens this fruit worldwide, is now backed by a major American food brand. The engineered banana is the work of plant scientists at Queensland University of Technology or QUT in Brisbane, Australia, and is drawing financial support from Fresh Del Monte Produce Inc. in Miami, Florida.

The Cavendish banana, the variety found in food and grocery stores worldwide, is grown worldwide, shipping 50 million metric tons of the fruit each year. Most of these bananas grow in tropical climates, with India, China, Ecuador, Colombia, Costa Rica, Brazil, Philippines, and Mexico as the leading producers. The Cavendish banana, however, is threatened by a fungus known as tropical race 4, or TR4, a type of Fusarium fungus that lives in soil. Since bananas, both Cavendish and related varieties are a staple crop for 400 million people, controlling TR4 has become a critical food security issue.

“TR4 is caused by a soil borne fungus that can survive in the soil for more than 40 years,” says QUT plant scientist James Dale in a university statement. “The fungus kills Cavendish and many other types of bananas and there are no effective chemical treatments. Resistance to the fungus is the best strategy.”

Research on the Cavendish banana and TR4 is a major part of the work done in QUT’s Centre for Tropical Crops and Biocommodities, which applies biotechnology and genomics to crops and other tropical plant species. Dale, the center’s first director, showed in a paper published in 2017 that wild-type bananas carry a gene called resistance gene analog 2 or RGA2 that helps original varieties resist the TR4 fungus. Field trials of genetically engineered Cavendish bananas expressing the RGA2 gene show they could could survive in the presence of TR4 fungi.

Next generation of TR4-resistant bananas

Dale says editing the Cavendish banana genome with Crispr will allow for natural expression of the RGA2 gene. “Our main gene editing strategy,” notes Dale, “is to activate the expression of the RGA2 gene in Cavendish creating a gene-edited banana resistant to TR4.” Crispr, short for clustered regularly interspaced short palindromic repeats, is a genome-editing process based on bacterial defense mechanisms that use RNA to identify and monitor precise locations in DNA.

QUT researchers are field testing gene-edited Cavendish bananas at La Manna Premier Group farm in northern Australia. La Manna Premier Group is a major Australian fresh produce grower and supply chain services company that co-funds research by Dale and colleagues on TR4-resistant bananas.

The collaboration with Fresh Del Monte aims to produce new varieties of gene-edited Cavendish bananas resistant to TR4 fungi at commercial scale. The work is expected to progress in stages over five years, and while QUT says the collaboration is a “multi-million dollar partnership,” precise dollar amounts were not disclosed.

“We see the potential with these revolutionary technologies,” adds Fresh Del Monte’s chief sustainability officer Hans Sauter, “and we are looking forward to putting these tools to work to solve real problems facing the world.”

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