Banana extinction: Scientists pushing to save popular fruit

Bananas are the world's fourth most important crop. Photo / Getty Images

When it comes to tropical fruits, Norwich probably isn't the first place that springs to mind. But here, in a drab research park at the edge of the East Anglian city, a team of banana experts led by a former Israeli naval commander is working feverishly to save the fruit from extinction.

"Bananas are the fourth most important food crop globally, it's the most consumed and produced food," says Gilad Gershon, chief executive of Tropic Biosciences.

The start-up, which moved to Norwich in 2016, consists of a team of almost 50 scientists and researchers working on editing the genes of bananas to protect them against diseases.

It's for a good reason. For more than 20 years, tropical race 4 (TR4), a soil-borne strain of the Fusarium wilt fungus, has been slowly making its way across the world from south-east Asia, threatening to wreak havoc on the global banana industry.

In 2013, the fungus was discovered on a farm in northern Mozambique, before making its way to Colombia, where it was detected last year, leading to a national state of emergency. Bananas are a major crop and a mainstay of the country's agricultural economy.

As the world's fourth largest exporter of bananas, the arrival of the disease in South America has created a problem for the industry. The disease disrupts the vascular systems of plants and can live in the soil for decades.

There is an additional problem.

Bananas are uniquely vulnerable to disease because a single strain of the fruit, known as the Cavendish banana, overwhelmingly dominates the global industry making it highly susceptible.

According to the Food and Agriculture Organisation of the United Nations, the Cavendish banana accounts for 50pc of global production, while constituting almost 100pc of the global export market, worth more than $13.6bn (£10.6bn).

"The disease is a significant threat for the banana sector, particularly for the Cavendish bananas, not only from the supply point of view but also for the economies of the banana producing countries and livelihoods of smallholder producers," says Fazil Dusunceli, agriculture officer at the United Nations' Food and Agriculture Organisation.

Tropic Biosciences, which raised $10m in a Series A round in 2018, has since been doubling down on efforts to find ways of protecting the Cavendish banana from wipeout.

Cavendish bananas are asexual, which means they can't be bred in a way that eliminates the genes putting them at risk, according to Gershon. So the company has put its gene-editing technology to work to mitigate challenges from the fungus.

"The impact is potentially catastrophic for the banana industry … the exposure here is massive because you have a single banana," he says. "The weight on our shoulders as a company today is very high. There's not a lot of people solving this massive banana issue in the world."

There is a lot at stake. The population of the Tropics will grow by over 500m people by 2030, accounting for half the world's population. This creates an unprecedented need for more productive and environmentally friendly agricultural production. Nor are concerns over a banana plight unwarranted.

In the first half of the 20th century, the Gros Michel banana, which went by the nickname "Big Mike", was the most popular variant of the fruit, with exports from Central America to the US and Europe dominating the trade.

The singular focus on Gros Michel, a small banana described as having a tartish aftertaste, proved to be lucrative but ran a risk. In the Fifties, the United Fruit Company, a US firm that established sprawling plantations in places such as Costa Rica and Guatemala, led to the development of so-called "banana republics" that forced economies into a dependence on a genetically limited crop.

Bananas are very popular among New Zealand shoppers. Photo / Getty Images

A collapse was inevitable. Amid growing rebellion from locals who demanded higher wages, the United Fruit Company's annual profits of $65m came under pressure when tropical race 1, a strain, of the fungal Panama disease, infected the fruit and brought commercial production to a screeching halt.

It's the kind of threat banana producers are desperate to prevent but the risk of history repeating itself, with an industry dependent on the export of a single type of banana again, is obvious.

For Gershon, it means that there is work to be done. After six years in the Israel Defence Forces, where he commanded a ship as a Lt Commander, the Tropic Biosciences boss made a foray into venture capital, becoming a senior investor at Pontifax Agtech, a Los Angeles-based fund specialising in food and agriculture technology.

"In that capacity I became more and more aware of the promise of gene editing from a financial perspective. It's a technology that significantly speeds up and simplifies the process of developing genetically-engineered plant products," he says.

For Gershon's Norwich-based start-up, which is also working on cutting the caffeine content of coffee, gene editing technologies have become a critical tool to protect the banana.

Originally based in Israel and the US, Tropic Biosciences picked Norwich as a location four years ago because of the supply of skilled local scientists from the university and the John Innes Centre, an independent international centre of excellence in plant science, genetics and microbiology.

Specifically, one of the main tools in the firm's arsenal of tools is CRISPR, a technology that significantly reduces the cost of editing genes – the essential coding for biology. It works by using a protein to cut away at sequences of DNA that might code for unfavourable traits.

At first, when the start-up began to look at bananas, it picked traits it described as "low-hanging fruit": extending the shelf-life of bananas and reducing the speed at which they turn brown. Then it recognised their potential to tackle the impending threat to the banana's survival.

Its technology works by taking a banana flower from a place like Colombia and reducing it to millions of stem cells in cultures. Then, sequences of the Cavendish banana genes that make it susceptible to TR4 fungus are cut out.

The cells grow back in a room lit with pink neon lights, set to a temperature of 26C. They then become edited seedlings that can be sent back out to the world for full-scale growth.

According to Dusunceli, emerging technologies like this offer the chance to "develop resistant varieties", but pose some issues. "The issue is agronomic performance of the products and acceptance by the producers and consumers," he says.

Ecuador is an important source of bananas around the world. Photo / Getty Images

Gershon recognises the challenges some people face in embracing food that has been edited, but is keen to highlight that the bananas it grows do not involve the injection of foreign DNA.

"People have very strong feelings towards bananas and the idea of this crop being potentially lost due to this disease highlights the need to address it," he says.

There are other difficulties. Once the disease is established in a field there is no way of eradicating it, which means the plot can no longer be used to grow the fruit. Areas impacted by the latest strain have reached 100,000 hectares globally, and as Dusunceli explains: "The risk of expansion is real".

The technology may also face some barriers. "The efficiency of taking the CRISPR into the cells is low. It's not like in humans, the plants have cell walls," says Dr Ofir Meir, chief technology officer at Tropic Biosciences.

But there appear to be few other options, particularly as the banana industry already walks a tightrope. "Panama disease and a few other very big diseases that are already quite spread have the potential to shift the balance from a slim margin to a losing industry," Gershon says.

The ultimate solution for experts would be the prevention of the disease with expert control and management before it reaches a banana field, but as Gershon indicates, the future of the banana could depend on the willingness of people to accept an artificially altered fruit. "It's hard for me to imagine today any solution not coming from gene editing."

SLIP UP: A COSTLY MISTAKE

The global banana trade is dominated by a single type of banana, the Cavendish, which constitutes almost 50pc of production and close to 99pc of the export market. How did this single banana come to dominate?

After the almost total wipeout in the Fifties of the Gros Michel in Central America, the banana which previously dominated before being wiped out by a fungus, the Cavendish started to see a boost in production as an alternative. It's slightly bigger than the Gros Michel, but less sweet.

"It's a good banana, it's tasty, it travels well," says Gilad Gershon, chief of Tropic Biosciences.

Named after a 19th century duke who received a shipment from Mauritius, Cavendish bananas won support as they suited the same soils as the Gros Michel, giving hope to farmers looking for a resistant variant. In the UK, where five billion bananas are eaten annually, almost every single one is a Cavendish banana.

Today a new strain of the disease that wiped out the Gros Michel threatens the Cavendish because of the lack of genetic diversity.

- The Telegraph