When two biotechnologists fly from Brisbane to Darwin on Saturday, they will drive the Kakadu road to Humpty Doo and eat what has the potential to become one of the more consequential mouthfuls of banana in the history of the planet’s most popular fruit.
Whoever bites first will not only become the first person to taste a genetically modified fruit grown in Australia, they shall have the first taste of the first GM banana approved for commercial production anywhere in the world.
The banana in question, dubbed QCAV-4, was granted final approval for human consumption by the Australian government in April. But at that time none of the 47 GM Cavendish banana plants produced by the Queensland University of Technology’s banana biotechnology program were bearing fruit.
The trial plantation near Humpty Doo is the result of 20 years of research and has borne bunches consistently over the last seven years. A team led by Prof James Dale regularly handled them – but they couldn’t risk so much as a nibble until regulators gave the green light.
“[QCAV-4] is a Cavendish,” Dale says. “The bananas look the same, they feel the same, they peel the same, they smell the same and, we’re 99.99% sure, they are going to taste exactly the same.
“It’s just that we haven’t been able to eat them.”
The reason Dale can be supremely confident that the QCAV-4’s flavour is identical to the Cavendish banana – which accounts for 97% of bananas grown in Australia and 99% of those exported in the world – is because his team has only removed a single gene from the 25,000 genes in a wild species of banana and inserted it into the chromosome of the Cavendish.
“And the gene that we put in has nothing to do with fruit quality at all,” Dale says.
Instead, the gene in question’s qualities relate to disease resistance.
Because commercial bananas are sterile, rather than sexually reproducing, they are propagated by cutting stems from a parent plant. This means that every single Cavendish banana ever grown is a clone of a single seed produced as a naturally occurring hybrid, probably more than 1,000 years ago.
Herein lies what Dan Koeppel, the author of Banana: The Fate of the Fruit That Changed the World, describes as the “paradox” of the banana. The banana, he writes, “is too perfect”.
This lack of genetic diversity makes the commercial bananas extremely vulnerable to an outbreak of bacterial disease and fungus that could unleash a “banana apocalypse”. The kind of apocalypse that wiped out the Western world’s first commodity banana, the Gros Michel – known as “Big Mike” – by the 1960s. Or the kind of outbreak that is, even now, marching around the world’s Cavendish plantations.
Kurt Lindsay could be walking past a patch of green and healthy-looking banana plants on his Snake Gully farm at Wamuran, north of Brisbane, when – with one glimpse of a single slightly yellowed stem – his heart will instantly sink.
“We call that ‘goldy-up-the-gills’,” he says. “Right then you know … and it’s devastating.”
Within a week, the previously healthy plant’s leaves will wilt. Inside, its clean, white vascular tissue will brown and wither like a smoker’s lungs. Nothing can be done to save the plant.
“There is no fumigation,” Lindsay says. “There is no chemical”.
So, with a swing of his machete, Lindsay will slice clean through the plant and leave it to rot where it lies. He will inject the severed stem with herbicide to make sure the underground rhizome never sends up shoots again. Then he will spray his knife and boots with disinfectant and let weeds engulf the felled plant, to stop people walking through that patch of earth again. “But you can’t stop the wallabies and the pigs and the dingos getting in,” he says.
You can’t stop the rain either. Panama disease is a soil-borne fungus spread not only by people and other animals, but also by water.
A drone shot shows two of Lindsay’s plantations side-by-side; one lush and green, the other a blasted patch of land. Pointing at the decimated field, Lindsay recalls that just 12 months ago it was flourishing. That was until heavy rains came and a Panama outbreak left no banana plant standing.
Snake Gully – and the rest of south-east Queensland – are afflicted by several strains of the fungal disease, including the one which wiped out Gros Michel. But it remains free of Panama tropical race 4, or TR4, which has already obliterated Cavendish from the Northern Territory and major exporters like the Philippines.
“Tropical race 4 is a whole different beast,” Lindsay says. “What we have is like prostate cancer, it takes them out slowly. TR4 is like pancreatic cancer; it eats things alive overnight.”
The heartland of the Australian banana industry, tropical north Queensland, produces more than 95% of the bananas eaten across the country. TR4 first showed up there in the Tully valley in 2015.
“We always said, ‘Once you get it, you’ve still got 10 years,’” says the chair of Australian Banana Growers, Leon Collins. “Now we are coming up right on 10 years from that first infection.”
The fact that TR4 has been contained to nine farms in the Tully valley for so long is testament to Australia’s biosecurity regime – and the willingness of growers to isolate their farms and enact strict protocols.
“It’s a totally antisocial bloomin’ thing,” Collins says of Panama. “You can’t go over to your neighbours and say g’day any more. Everyone’s sort of locked down in their own little world.”
The scale of the threat leaves growers no choice but to comply.
“[Panama] has got the potential to wipe out everything out here,” Collins says. For him, the threat was enough to switch one of his family’s two banana farms in Tully to sugar cane.
The sacrifices of growers to slow the spread of Panama, he says, has bought the industry valuable time as scientists scramble to develop fungus-resistant replacements for the Cavendish. Genetic modification is billed as an option of last resort as several major institutes around the world pursue conventional breeding programs in a quest to save – or replace – the Cavendish.
Dale says these “exceptional scientists” have cracked how to create new cultivars using more traditional means. There is a very good chance someone, somewhere will develop new Panama-resistant bananas in this way, he says.
Yet in order to be commercially viable replacements, the bananas of the future must also retain the flavour, high yield and thick skin that allows Cavendish to be transported around the world.
“That is very challenging,” Dale says.
While his QUT team is proving laboratory-conceived bananas are a viable alternative solution, the biggest challenge the QCAV-4 will face is not a fungus, but import bans and consumer unease around GM food.
So Dale’s team is working on a related, though perhaps more publicly palatable, branch of science: gene editing. Instead of adding genes from one type of banana into the chromosome of another, gene editing essentially switches on – or switches off – genes already found within, say, a Cavendish.
Meanwhile, growers like those at Snake Gully just want a marketable banana that can resist the Panama disease striking down their plants. Lindsay says he would plant a QCAV-4 tomorrow if he could get his hands on one, and is confident his customers would come around to it too.
“They haven’t crossed Dolly the sheep with a banana,” he says. “That is the banana you’re going to get – or you’re probably not getting one at all.”
