Dan Koeppel's BlogBananas, Los Angeles, and Transit Geekery

Australian banana researcher James Dale. Image: QUT

The race to save our supermarket banana from disease is on, and a scientist in Australia – aided by a grant from the Gates Foundation – says that he and his team have developed a genetically modified version of the fruit (the term they use is “biofortification”) that successfully resists the blight that has destroyed much of the banana industry in his country, and that threatens the world’s entire banana crop. I interviewed James Dale for my book. Back then, he talked about how difficult banana breeding is. That remains the case – but this development is a major breakthrough, though he estimates that it will be as long as decade before the fruit he’s working with truly proves its worth.

I first wrote about the breakthrough last year. Here’s a more extensive interview with Dale that I conducted in January. In it, he gives details on the project – and where it might be going.

DK: Panama Disease is highly transmittable – I wonder about how you’re able to actually test these resistant plants that you’ve developed, especially in a country that’s already got a huge problem with the disease. Aren’t you and the Australian banana industry concerned that – since you have to expose these plants to PD – you might inadvertently let something escape?

JAMES: Needless to say, there would be concern about doing those challenges even in the glasshouse. So yes, the bio-security people are very, very concerned about this. Our tests are either going to be conducted where the disease already exists – in the Northern Territory – but also in Southeast Asia. Right now, we’re negotiating where to conduct those trials.

DK: So right now, you’ve only tested against Tropical Race 4 in the greenhouse?

JAMES: No, we haven’t tested against Race 4 in the greenhouse – we’ve so far only tested against Race 1 in the greenhouse.

Note: Panama Disease has different variations. Tropical Race 1 is the “original” version that killed the first commercial banana, the Gros Michel. The Cavendish – our banana – replaced that fruit in the 1950s and 1960s because it was immune to Race 1. Tropical Race 4 appeared in the 1990s, shocking the banana world because it affected the Cavendish, and beginning the race to find a remedy for the blight. The technical name for these disease is “Fusarium Wilt.”

DK: Would resistance to Race 4 necessarily be carried over?

JAMES: We believe so – the hypothesis is that there’s no reason to think that the genes we’re working with in Cavendish won’t provide resistance to Race 4.

DK: Cavendish is already resistant to Race 1 – that’s why it was adopted – so how is that a legitmate test?

JAMES: We have generated transgenic Lady finger expressing the resistance genes. Lady finger is susceptible to both Race 1 and tropical Race 4. We have challenged these transgenic lines in the glasshouse with Race 1 and have identified a number of highly resistant lines. The resistance strategy is not targeted to Race 1 but is targeted to inhibiting a basic infection process of Fusarium. Therefore, we believe there is a reasonable chance that the genes that provide resistance to Race 1 in Lady finger will also provide resistance to Race 4 in Cavendish. But we still need to do the challenges.

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