agriculture biology Genetics Plants

Scientists at India’s NIPGR Create a Longer-Lasting Tomato (Studying The Regulation of Fruit Ripening)

Author’s note: This would seem to be the week for vegetables I hated as a kid. Yesterday was onion, today tomato, if there’s a story about brinjal/eggplant in the next few days we’ll have hit all the big ones. 😉

Ripening tomatoes. Photo: Photos_by_Lina, fickr (click to see photo in its original context)

I was recently pointed to an early publication paper that went up on the Proceedings of the National Academy of Sciences website on Monday, where a research group at India’s National Institute of Plant Genome Research describes two genes from tomato that, when knocked down by RNAi*, result in tomatoes that can remain ripe but not spoiled for up to three times as long as tomatoes where these two genes function normally.

Their approach targets specific genes involved in breaking down certain proteins found in the cell walls of tomatoes (in fact in the cell walls of all plants). Breaking down the cell wall is a key part of ripening in fruits (which the tomato is, botanically if not culinarily). Which makes sense if you’ll think about it for a moment. One of the traits we associate with ripening is getting softer, from bananas to peaches if it’s still crunchy when you bite into it, it wasn’t ripe. What makes plants stiff and crunchy? The strength of their cell walls. Since, unlike vegetables, fruits WANT to be eaten**, as they ripen they begin to break down their cell walls to make themselves more appealing to passing animals. Unfortunately, ripening and spoiling are, in a lot of ways, the same process. If fruits aren’t eaten when they become ripe, they continue to get softer, transitioning from delicious looking -> unappetizing -> inedible -> a puddle of mush on your kitchen counter.

Preventing ripening entirely is relatively easy, and there are plenty of known mutants in tomatoes and other species that never ripen (these naturally mutant tomatoes stay green and hard no matter how long you wait). But getting part of the way to ripeness but stopping before crossing the line into spoiled is a much less tractable problem.

Feeding the world Plants

Biodiversity and Genetic Engineering Aren’t Mutually Exclusive!

The work of plant breeders and the naturalists who catalog so much of the genetic diversity passed down over 400 generations*, have done far more to feed people than genetic engineering thus far. The reason I spend so much time talking about genetic engineering (and to a lesser extent mutation breeding) isn’t because I think the techniques are more important than breeding using the existing diversity of crop plants and their wild ancestors, it’s because genetic engineering (and once more to a lesser extent mutation breeding) are the techniques that are subject to the most misinformation and opposition. If I had to choose, for the entire world, between marker assisted selection and genetic engineering, I’d choose marker assisted selection in a heartbeat. But we don’t have to chose.

Consider three cases:

agriculture Feeding the world Plants

Edible Cottonseed

Cotton and cotton seeds photo credit: Gonzalez's tongue, Flickr (click to see photo in it's original context)
Cotton and cotton seeds photo credit: Gonzalez's tongue, Flickr (click to see photo in it's original context)

Over 102 million bales of cotton (more than 24 million tons of cotton) were grown around the world last year. I wouldn’t surprise me to hear cotton called the single most important (and widely cultivated) food crop on the face of the planet. But does it have to be a non-food crop?

Clearly no one (nor any livestock) wants to eat the cotton fibers themselves, but they aren’t the only product of the plant. After to cotton plant flowers, the cotton fibers grow around the developing seeds. The combined mixture is harvested each year, after which the seeds are removed from the cotton fibers before the cotton is baled and sold.*

The seeds of the cotton plant are full of protein and oils and since cotton is already grown as a source of fiber (and the seeds are even harvested and sorted out of the cotton fibers already) adding them to the food supply** doesn’t require any further land to be cultivated or increased input costs. Obviously there is a catch…

agriculture Feeding the world

Bt Rice in China

Reuters has a story up, based on anonymous sources, that China has just approved a government developed strain of bt rice*. Bt crops express a protein isolated from Bacillus thuringiensis a bacteria used by organic farmers to control insects. The introduction of bt crops (primarily corn and cotton) has lead to substantial reductions in the use of insecticides. China plants more than 100,000 square miles of land with rice each year, so the environmental and economic** impact of being able to reduce insecticide applications would be substantial.

China is also in a unique position when it comes to commercializing any form of genetically engineered rice, as the world’s largest producer of rice, but only a small next exporter*** China stands to benefit from any improvements to rice, and is largely immune to pressure from food importing countries such as the members of the European Union. China has also invested (and continues to invest) billions of dollars in developing their own, publicly-funded, domestic crop research and breeding which has kept their per acre crop yields trending upwards, and now means they’re prepared to make the leap to genetically engineered food crops (they’ve had bt cotton for some time) with home-grown technology, killing any narrative about this being western tech foisted off on the developing world.

Crop Profiles Plant breeding Plants

Not Genetically Engineered: Grapes

New York Grapes. Concords I believe, though it's been several years so I may be remembering wrong.
New York Grapes. Concords I believe, though it's been several years so I may be remembering wrong.

Scientific Name: Vitis vinifera

Supposed Genetically Engineered Trait: Large size/seedlessness

The Real Story:

Seedless grapes are descended from several different mutations that all result in the developing embryos of grape seeds to abort prematurely*. You can still find the tiny dead remnants of seeds in seedless grapes. Of course being seedless raises a new question: How do plant breeders work with seedless grapes?

agriculture Feeding the world food Fun With Numbers

About the herbicide application report that’s floating around

I’m sure everyone who follows the genetic engineering debate has heard about the report from The Organic Center which lays a net increase in pesticide usage at the feet of genetically engineered crops. So I finally found a link to the report itself [warning pdf, also 69 pages]. I’m neither a statistician nor an agronomist (despite my awesome ISU hat which has exactly that slogan), so I’m not qualified to confirm or refute the numbers they put forward. Hopefully we’ll see more detailed analysis on that end from someplace like Biofortified or Sustainablog. I now have some analysis of the methodology of the report itself, tracked down by gntis on the biofortified forums. What I can do is given a bit of the broader context about the context of their numbers and what they don’t mean. This post will be in the following format:

  • The 318 million pounds in context
  • Chemicals are different
  • –Different Toxicity
  • –Different Persistance in the Environment
  • Herbicide resistant weeds
  • One trait vs a technology

318 Million Pounds in Context

Example tweet:

Pesticide use has skyrocketed by 318 million lbs (in last 13 years) with use of #GMO seeds!

Let’s put that number in perspective.

agriculture Feeding the world

Biotech Wheat

Nature Biotechnology has an article well worth checking out (if you have journal access anyway) about the story of biotech wheat. No genetically engineered wheat is commercially grown today, nor has it been in the past.  Monsanto came close to releasing an herbicide tolerant variety several years ago, but didn’t because of fear that American farmers would lose valuable markets for our wheat exports. I speculated that genetically engineered wheat runs into more consumer opposition because we eat more wheat in recognizable forms (mostly bread and pasta) than we do crops like corn, soybeans, and canola.

Anyway, two new developments seem to have prompted this article.

agriculture Feeding the world

Greenpeace offers marker assisted breeding

Greenpeace on Friday called on the International Rice Research Institute to abandon its genetic engineering program as the environmental activist group offers marker assisted breeding as a safe alternative to bioengineering.


Dear Greenpeace,

I would like to call upon you to abandon your campaign against genetic engineering and offer up an alternative priority your organization could focus on to the greater benefit of the world we all share: Fighting man-made global warming.


Now you could argue greenpeace already is opposed to global warming. And you’d be right. They are. I guess my offering it to them looks pretty stupid doesn’t it?

The same could be said of greenpeace offering marker assisted selection to the plant breeding community that pioneered the technique and is taking full advantage of it, and has been for years in both the private and public sectors. Case in point:

agriculture Crop Profiles Feeding the world Plants

Genetically Engineered Crops: Papaya

Photo Reeding, Flickr (Click for photo stream)
Photo Reeding, Flickr (Click for photo stream)

Scientific Name: Carica papaya

Genetically Engineered Trait: Resistance to the papaya ringspot virus

Details of Genetic Engineering:

In the 1990s papaya ringspot virus was in the process of wiping out the Hawaiian papaya industry, then the second largest fruit industry in Hawaii. Conventional approaches such as selective breeding for resistant papayas or attempting to grow trees in isolation had failed. The virus is transmitted by small sap-sucking insects such as aphids. Infected papaya trees can be recognized by the discolored rings on their fruit (that the virus gets its name from) yellow leaves, and most importantly from a papaya farmer’s perpsective a 60-100%* loss of fruit production.


bt: The Bacteria and the Protein

I figured if I am going to do a review of genetically engineered crops, I needed to address the other major traits besides resistance to herbicides presently on the market. This one addresses a family of proteins found in the bacteria Bacillus thuringiensis that can kill insects.

Anyone who reads about the public policy debates swirreling around genetically engineered crops will be familar with the two letter abbreviation ‘bt’ as in bt corn, bt cotton, bt ginseng (the last is fictional). What always surprises me is that some people STOP reading before they come across an explanation of what bt stands for. Just typing bt into google won’t bring up a relevant result until the 30th hit (two letters just isn’t very unique). I have talked with people who are convinced bt stands for everything from biologically treated to BioToxin. It doesn’t.

Golden Eyed Lacewing Adult. It's not much use, but the larva vicious predators of certain plant pests. (Photo public domain courtesy of USDA. You guys are awesome!)
Golden Eyed Lacewing Adult. It's not much use, but the larva vicious predators of certain plant pests. (Photo public domain courtesy of USDA. You guys are awesome!)

The name actually comes from a species of bacteria called Bacillus thuringiensis. Different substrains of the species carry different members of a family of genes that code for Cry proteins (and separately can also carry genes that code for Cyt proteins*), which can kill insects. Finding chemical or biological means to kill insects isn’t that hard. What makes the Cry proteins noteworthy is how selective they are in their killing. A given Cry protein is dangerous to only a small subset of insect species. And that’s important, because, for every** western corn rootworm, european corn borer, or earworm there are also benign or even beneficial insects in and around fields like lacewings, trichogramma wasps, or those rootworm eating nematodes I talked about a couple of days ago, which aren’t insects, but also harmed by insecticides. (Agro-ecology is beyond my field of expertise, had to call up my tipster from the previous post to get this list) When a crop is genetically engineered to produce one of the dozens of Cry proteins discovered in Bacillus thuringiensis, it replaces or reduces the spraying of insecticides to control insect pests, with positive effects on insect biodiversity.