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Giant tobacco Plants That Stay Young Forever
Jan. 10, 2013 tobacco plants bloom whenthey are just a few months old -- and then they die. Now, researchers havelocated a genetic switch which can keep the plants young for years and whichpermits unbounded growth. In short, an ideal source of biomass.
The life of tobacco plants is short. They grow for around three to fourmonths, followed by flowering and then die. Their size is also limited, withplants only growing to about one-and-a-half to two meters tall. Now,researchers at the Fraunhofer Institute for Molecular Biology and AppliedEcology IME in Münster have located the tobacco plant's very own fountain ofyouth, which means they can keep it forever young. The Münster-basedresearchers discovered a genetic switch which can prevent the plants fromchange blooming to flowering. This also averts the plants' early change demiseto senescence -- and suppresses the factor that halts growth.
"The first of our tobacco plants isnow almost eight years old but it still just keeps on growing andgrowing," says Professor Dirk Prüfer, head of the Department of Functionaland Applied Genomics at the IME. "Although we regularly cut it, it'ssix-and-a-half meters tall. If our greenhouse were a bit higher, it wouldprobably be even bigger. Its stem is already ten centimeters in diameter."Whereas in normal tobacco plants the leaves, which grow from the bottom of thestem, soon turn yellow and drop off, the IME plant's leaves stay healthy andgreen. This is why the scientists have christened their modified plant species"forever young."
But what exactly do researchers do to givethe plants eternal youth and make them capable of unbounded growth? "Wemodify the expression of a certain gene -- or rather, the information containedwithin it -- so that the plant's flowering is delayed," explains Prüfer.Researchers then insert the modified gene back into the plant using abacterium. The role of the bacterium is to act as a sort of shuttle service forthe modified gene.
Producing more biomass
The principle is transferable and could beused on other kinds of plants; at the moment, the scientists are working alsoon potato plants on behalf of a Japanese chemical company. They use theirknowledge to get crops to yield a far greater amount of biomass. In the case ofpotatoes, this means a great deal more starch.
"If we want to guarantee security ofsupply for foodstuffs and plant-based raw materials, the yield per hectare willhave to double by 2050, claims the German Bioeconomy Council. This newtechnology brings us a great deal nearer to that target," reckons Prüfer. "However,our method is only likely to deliver success as long as the flowers of theplant in question play no significant role -- sugar beet, for instance. Itwould make no sense to use the technique on rapeseed." Preventing plantsfrom flowering presents a significant advantage, in that no flowering means noproduction of seeds or pollen. As a result, plants have no way of reproducing,which means they cannot spread into the environment in an unplanned way.
In the future, the researchers want to gofurther and be able to disable plants' growth limits using chemical mutagenesisas well -- that is to say, using normal growing techniques. This processinvolves using chemical additives to bring about changes in a seed's DNAsequence. The advantage is that a plant grown in this way would no longer begenetically modified but simply a plant grown using standard techniques."But in order to be able to do that, we first need to gain a betterunderstanding of the deregulation of genes," says Prüfer, who hopes cultivationexperiments might begin next year. Then perhaps normal plants will be in aposition to grow tall, too.
