Unit 8. Coffee

Script 18. Salt-tolerant rice

Nuclear-powered crops

Physics meets biology in a project to breed better strains of rice.

Those who turn their noses up at "genetically modified" food seldom seem to consider that all crops are genetically modified. The difference between a wild plant and one that serves some human end is a lot of selective breeding - the picking and combining over the years of mutations that result in bigger seeds, tastier fruit or whatever else is required.

Nor, these days, are those mutations there by accident. They are, rather, deliberately induced, usually by exposing seeds to radiation. And that is exactly what Tomoko Abe and her colleagues at the Riken Nishina Centre for Accelerator-Based Science in Saitama, outside Tokyo, are doing with rice. The difference is that Dr Abe is not using namby-pamby x-rays and gamma rays to mutate her crop, as is the way in most other countries. Instead she is sticking them in a particle accelerator and bombarding them with heavy ions - large atoms that have been stripped down to their nuclei by the removal of their electrons. This produces between ten and 100 times as many mutations as the traditional method, and thus increases the chances of blundering across some useful ones.

Dr Abe's plan is to use these mutations to create salt-tolerant rice. She has tried to do that several times in the past, but the result did not taste very nice. Her latest effort was stimulated by the flooding with seawater of almost 24,000 hectares of farmland by the tsunami which followed an earthquake in March last year. Salt-tolerant rice would, though, be of much wider use than just restoring the paddies of Miyagi prefecture and its neighbours, the worst affected part of the country, to full productivity. About a third of the world's rice paddies have salt problems, and yields in such briny fields may be half what they would be if the water in them were fresh.

To induce the mutations, Dr Abe bombarded germinating seeds with carbon ions for 30 seconds. She then planted them in fields in Miyagi. Of 600 seeds that have undergone this treatment, 250 thrived and themselves produced healthy seeds.

The next stage of the project, to be carried out this month, is to take 50 grains from each of the successful plants and repeat the process with them. The resulting specimens will then be sorted and the best (i.e., those that have flourished in the saline soils of Miyagi's paddies) selected for crossbreeding, in order to concentrate desirable mutations into reproducible lines of plants.

The result, Dr Abe hopes, will be a viable salt-tolerant strain that is ready for market within four years. With luck, this time, it will be a tasty one as well. (From The Economist, May 5, 2012)

Script 19. Decaffeinating waste

Brewing a solution

Genetic engineering may clean up the processing of coffee.

Coffee is big business. One consequence is a lot of caffeine-rich waste which cannot be thrown away willy-nilly because caffeine is a pollutant. It inhibits both the germination of seedlings and the growth of adult plants, so it must be collected and dumped at approved sites.

This is a pity for two reasons. One is that it increases the cost of a cup of coffee. The other is that the waste is rich in nutrients. If it could be decaffeinated, it might be used as animal feed - thus adding to coffee companies' revenues rather than subtracting from them. But that would require a cheap way to decaffeinate it. Which is what Jeffrey Barrick of the University of Texas at Austin and his colleagues hope they have found. Their research, published in Synthetic Biology, suggests the answer lies with genetically modified bacteria.

The idea of using bacteria to decaffeinate waste is not new. Past studies showed that a species called Pseudomonas putida can chew the molecule up. But it does so in small quantities, and no one knew enough about it to work out how to increase its efficiency. Dr Barrick thought the best way round this was to take the caffeine-chewing mechanism out of P. putida and put it into Escherichia coli, a species biologists are good at manipulating.

He and his colleagues therefore extracted the cluster of P. putida's genes that encode the caffeine-chewing enzymes and transferred them into E. coli. And not just any old E. coli. The strain they picked lacked a gene from the pathway the bug usually uses to synthesise guanine, one of the four chemical bases that act as the genetic code in DNA. This was to test whether the transfer had worked, because the transplanted biochemical pathway turns caffeine into xanthine, a molecule E. coli can make into guanine without the missing gene. Since nothing can reproduce without guanine in its DNA, the researchers had merely to sit back and see if their engineered bugs multiplied in the presence of caffeine. Sadly, they didn't.

An examination of the problem showed that the transferred gene cluster was missing a crucial piece. That, they fixed using a patch from a third species, Janthinobacterium. Then they tried again. This time the bacteria bred like billy-o.

The next step will be to see if what works in a lab also works on an industrial scale. If it does, then coffee companies should see their costs reduced, and other producers of waste that requires specialised disposal will have a new line of inquiry to pursue. (From The Economist, Economist April 06, 2013)

Script 20. High-tech farming

The light fantastic

Indoor farming maybe taking root.

A grey warehouse in an industrial park in Indiana is an unlikely place to find the future of market gardening. But it is, nevertheless, home to a pristine, climate controlled room full of eerily perfect plants. They grow 22 hours a day, 365 days a year in 25-foot towers, untouched by pests and bathed in an alien pink light.

Critical to this $2.5m techno-Eden, run by a firm called Green Sense Farms, are the thousands of blue and red light-emitting diodes (LEDs) supplied by Philips, a Dutch technology firm. The light they give off is of precisely the wavelength craved by the crops grown here, which include lettuce, kale, basil and chives.

The idea of abandoning the sun’s light for the artificial sort is not new. It offers plenty of advantages: no need to worry about seasons or the weather, for instance, not to mention the ability to grow around the clock (although a couple of hours a day are necessary, says Gus van der Feltz of Philips, for the plant equivalent of sleep). Moving plants indoors allows them to be coddled in other ways, too. Water can be recycled continuously, and sensors can detect which nutrients are missing and provide them in small, accurate bursts.

However, LEDs offer a host of benefits over traditional, fluorescent growing lights. For one thing, they are far more efficient, which helps to keep electricity bills down. High efficiency means less heat, which makes air conditioning cheaper. Being cooler, the lights can be placed closer to the plants, so the crops can be planted more densely. The wavelengths of the light can be fine-tuned so that lettuce is crisper, or softer, says Robert Colangelo, the president of Green Sense Farms. Your correspondent tasted soft, sweet kale nibbled straight off the plant. It was delicious.

The crops grow faster, too. Philips reckons that using LED lights in this sort of controlled, indoor environment could cut growing cycles by up to half compared with traditional farming.

That could help meet demand for what was once impossible: fresh, locally grown produce, all year round. Hydroponic, naturally lit greenhouses, such as those built by Bright Farms, a firm based in New York, are already supplying produce to cities such as Chicago and New York. Green Sense Farms is not the first to try growing under LEDs, and despite their efficiency, energy costs have been a challenge for its predecessors. But Mr Colangelo is confident. LEDs are becoming cheaper all the time, and the involvement of Philips, which has invested heavily in the technology, suggests that costs can fall further.

Farms such as these are unlikely to be suitable for heavy crops like corn and potatoes which grow pretty efficiently in vast fields. But if Green Sense Farms can prove its commercial worth, this form of farming could become widespread for leafy greens and other high-value crops. A new national climate assessment, published on May 6th, sets out the threats that American agriculture is facing, such as growing numbers of insects and other pests and a rising incidence of bad weather. Indoor farming is, happily, immune to both. (From The Economist, May 17, 2014)