Author: Luigi Guarino

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I say kumato

The FreshPlaza piece on the kumato is not very long. But it does manage to squeeze in a lot of interesting information. The kumato is a tomato that ripens from green to dark brown. It is the result of a conventional breeding programme which involved a wild species. And it is just coming up to its first harvest in Australia. This definitely deserved more investigation.

There’s no doubt it looks pretty extraordinary. But the most intriguing thing about the kumato is that the wild species involved in its development may be from the Galapagos.

Now, Lycopersicon cheesmaniae from the Galapagos Islands has been used to breed dark orange tomatoes before, though it does not have a dark brown skin like the kumato. ((This species was actually published as L. cheesmanii, after Evelyn Cheesman, but that was incorrect, as the Latinists among us will know, as Ms Cheesman was a woman and the specific epithet therefore requires a feminine ending.)) Check out this excerpt from an article celebrating the late great tomato geneticist and explorer Prof. Charles M. Rick in 1997, five years before his death:

Rick’s research led him on 15 genetic scavenger hunts to Andean South America, the homeland of the tomato, where he hunted for wild tomato varieties carrying useful genes. Among his discoveries were wild tomatoes growing near the tidelands of the Galapagos Islands, despite salty sprays that would have stunted or killed a domestic tomato plant.

Or again:

An excellent lecturer, Rick was much sought after by universities who valued both his rigorous science and his humor and flair for storytelling. A perennial favorite involved his frustrations in trying to germinate wild tomato seeds collected from the Galapagos Islands. The emerging mystery of how the plants reproduce in the wild was only resolved after the seeds were “processed” by passing through the digestive track of a Galapagos tortoise, resulting in vigorous seedlings.

The kumato should actually be the Kumato©. It was bred by Syngenta, and first released in the UK in about 2004, I think. But the Roguelands Heirloom Vegetable Seeds Company also has 40 different dark brown to black-skinned varieties in its collection, and says black tomato varieties first appeared in the 19th century in Ukraine.

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Vitamin C mystery solved, again

I blogged three months ago now about what was touted at the time as the final elucidation of the metabolic pathway by which plants make vitamin C. The piece in EurekAlert! which I quoted says:

UCLA and Dartmouth scientists have identified a crucial enzyme in plant vitamin C synthesis, which could lead to enhanced crops. The discovery now makes clear the entire 10-step process by which plants convert glucose into vitamin C, an important antioxidant in nature… It was not until 1998 that a biosynthetic pathway was proposed to explain how plants make this compound. Research confirmed much of the pathway, although one crucial missing link continued to baffle scientists and remained unknown until this new research.

So imagine my surprise when I read this today in FreshPlaza:

Agricultural scientists say they have uncovered the last big secret of vitamin C in plants, and it will create the chance to naturally breed healthier fruits. The breakthrough in understanding just how plants manufacture vitamin C will enable state science company Hortresearch to identify DNA markers for individual plants naturally producing high levels of the vitamin… Hortresearch’s science general manager, Dr Bruce Campbell said the team had isolated the last undiscovered enzyme and proved it controlled vitamin C in plants. The enzyme was the last step in a chain of research begun overseas nearly 80 years ago by scientist seeking to understand how plants produce vitamin C.

The research comes from New Zealand rather than the US, and was carried out on wild and cultivated kiwi fruit species with contrasting levels of vitamin C, rather than on Arabidopsis, but otherwise sounds as if it was aimed at solving pretty much the same problem. No way to tell from these brief summaries of the two pieces of work whether they came up with the same answer, though. That will take some more digging.

Anyway, it does seem likely that gene-jockeys will be falling over themselves all too soon trying to engineer a higher vitamin C apple, marula or whatever. Good luck to them. I’m no Luddite. But our friend Ola does have a point in his comment on my recent post on potatoes. Would it not maybe be easier and more cost effective to try to get people to eat foods which are naturally high in vitamin C?