Genetic discovery points the way to much bigger yields in tomato, other flowering food plants

Dec 26, 2013
A mutation in the hormone that controls flowering postpones when a plant stops producing flowers, yielding many more fruits. Credit: Cold Spring Harbor Laboratory

Every gardener knows the look of a ripe tomato. That bright red color, that warm earthy smell, and the sweet juicy flavor are hard to resist. But commercial tomato plants have a very different look from the backyard garden variety, which can grow endlessly under the right conditions to become tall and lanky. Tomatoes that will be canned for sauces and juice are harvested from plants that stop growing earlier than classic tomato varieties, and are therefore more like bushes. While the architecture of these compact bushy plants allows mechanical harvesters to reap the crop, the early end of growth means that each plant produces fewer fruits than their home garden cousins.

But what if commercial tomato growers could coax plants into producing more fruit without sacrificing that unique and necessary bushy plant shape? Today, CSHL researchers announced that they have determined a way to accomplish this. Their research has revealed one genetic mechanism for hybrid vigor, a property of plant breeding that has been exploited to boost yield since the early 20th century. Teasing out the hidden subtleties of a type of hybrid vigor involving just one gene has provided the scientists with means to tweak the length of time that bushy tomato varieties can produce flowers. In these plants, longer flowering time substantially raises fruit yield.

First identified at CSHL by George Shull in 1908, hybrid vigor – or heterosis, as biologists call it – involves interbreeding genetically distinct plants to generate offspring more robust than either inbred parent. It has been used for decades to improve agricultural productivity, but scientists have long debated how and why it works.

In his previous work, CSHL Associate Professor Zach Lippman and Israeli colleagues identified a rare example of hybrid vigor involving a genetic defect in the gene that makes florigen, a hormone that controls the process of flowering and flower production. The mutation dramatically increases tomato yields in bush tomatoes, and Lippman and his team, led by postdoctoral researcher Ke Jiang, set out to understand the mechanism behind this remarkable result.

They found that bushy plants with a mutation in one of the two copies of the florigen gene, producing half as much florigen as without the mutation do, postpone the moment when they stop producing flowers. This, in turn, leads to many more fruits overall. "This is because," Lippman explains, "bushy are highly sensitive to the amount, or dosage, of the florigen hormone, which alters plant architecture – that is, how many flowers can form before growth ends. These discoveries lead to an exciting prediction: that it may be possible to tweak florigen levels to increase yields even further."

Lippman's team also studied florigen mutants in another plant, the crucifer weed known as Arabidopsis that is a cousin of crops like broccoli and cauliflower. Although they did not see the same increase in yield, they did observe similar changes in plant architecture because of florigen dosage sensitivities. These results suggest that it may be possible to manipulate florigen in a wide variety of flowering species to increase yields.

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More information: "Tomato Yield Heterosis is Triggered by a Dosage Sensitivity of the Florigen Pathway that Fine-Tunes Shoot Architecture" appears online in PLOS Genetics on December 26, 2013. The authors are: Ke Jiang, Katie Liberatore, Soon Ju Park, John Alvarez, and Zach Lippman. www.plosgenetics.org/doi/pgen.1004043

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User comments : 6

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Whydening Gyre
4.7 / 5 (3) Dec 26, 2013
More lycopene for everyone!
Iochroma
5 / 5 (1) Dec 26, 2013
The genes that influence Lycopene have already been noted and high-Lycopene varieties have been offered for decades; they are not popular...
goracle
not rated yet Dec 26, 2013
The Attack Of The Killer GMO Tomatoes! Coming soon to overactive imaginations near you!
Lorentz Descartes
not rated yet Dec 27, 2013
Cool research. If you go to the trouble of growing a fully mature plant structure, you might as well get the the most of it's photosynthesis thereafter. Not have it stop at a certain point.

In a way, this could make tomatoes more like their cousins, potatoes. Those keep growing and enlarging tubers until the first frosts. And that's totally unlike crops like wheat, where a whole harvest can fail entirely because it didn't ripen fully.

The 'green revolution' has not ended. It just started.
Kev_C
not rated yet Dec 28, 2013
The Attack Of The Killer GMO Tomatoes! Coming soon to overactive imaginations near you!

I didn't read it as anything to do with genetic modification. More like hybridisation. But then the way these new innovations are written up these days gives me the impression that the authors are only too aware of the uproar that GM technology causes. So now they word things somewhat differently to hide the true nature of what they are doing. That way tb avoid any controversy.
If it is genetic modification it is yet another food product I won't be buying. We don't actually need more food. We need better distribution, storage and consumption rates for the food we already produce. Plus we should stop using food crops for biofuels. How dumb is that? Claiming food shortages when none exist and at the same time converting food into car fuel? Madness of the most insane variety. They must think we're all stupid to pull a stunt like that.
EnricM
not rated yet Dec 28, 2013
Yielding more fruit... and needing more chemicals impoverishing the soil.
We already know ways of improve yield in crops without GMO, that has never been a problem at all. This was indeed done already at a massive scale within the so called "Green Revolution" with the result of soil loss at a scale never seen before.
GMO are fancy and hip for us nerds, but unfortunately they can't just ignore limiting factors such as soil nutrients, etc. And if you have a plant that uses it's energy for something else like creating insecticides or just flowering longer, the energy and resources spend will be detrimental to other qualities such as nutritional value... unless you add chemicals, of course, but then the very purpose of having a GMO is defeated.

GMO have been around for a few decades already and none of the promises have been mad true: No greening of deserts, no stopping hunger in the poor countries...

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