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Gene that withstands salinity could mark agricultural boon
Posted By David Brinn On July 4, 2006 @ 8:00 pm In | No Comments
The Dead Sea fungi as observed under a microscope.Imagine what it would mean for the world hunger problem if farmers could grow wheat and other crops on land considered unsuitable for agriculture.
That day may be coming soon, after Israeli researchers from the Institute of Evolution of the University of Haifa, have succeeded in isolating a gene that withstands salinity.
“The research will contribute to a significant increase in the amount of arable land available for agriculture,” said the institute’s director Professor Eviatar Nevo, who initiated and spearheaded the pioneering research.
Of the earth’s 57 million square miles of land, approximately 12 million square miles are arable – meaning land that can be used for growing crops. However, arable land is being lost at the rate of over ten million hectares per year.
Nevo’s research will make it possible to grow plants, including crops, in saline earth, a development that will contribute in the future to a true revolution in saline agriculture throughout the world.
Saline agriculture is the production of crops on land that is affected by salt. Too much salt in soil or in irrigation water will inhibit the growth of most crops, or may even kill them. Saline soils are found in arid lands, in coastal deserts, and where arable land has been ruined by poor farming practices.
Modern methods of irrigation and fertilization of crops has caused much of the arable lands around the world to become saline. This is especially true in drylands because of the high rate of evaporation, which leaves the salt behind. More and more farmers are forced to plant crops on marginal lands and to use soil that was once arable but now has a high saline content.
To prove their research, Nevo’s team went to the mother of saline content – the Dead Sea – one of the most hypersaline bodies of water in the world with a saline concentration ten times that of the oceans.
“Back in 1998, we discovered 77 different types of filamentous fungi in the Dead Sea, some were rare and sporadic, and others were much more common and even reached the bottom of the sea 300 meters down,” Nevo told ISRAEL21c.
“We became interested in the fungi’s genetic resources – what made them thrive in the salty Dead Sea.”
In the current study, Eurotium herbariorum, a common fungal species, was isolated from the lake. One of Nevo’s doctoral students, Yan Jin, from China, then isolated and sequenced the HOG gene that is responsible, in concert with other genes, for the fungus’ ability to defend itself from the salinity of the Dead Sea.
The gene was introduced into ‘saccharomyces cerevisiae’ – better known as baker’s yeast – and the team observed that resultant transgenic yeast was able to tolerate more salt than normal, especially in resisting large temperature changes. The researchers found that in comparison to yeast that was not genetically engineered, the yeast that had been genetically transformed by the insertion of the HOG gene was more durable in saline or highly oxidative environments and also able to better withstand extreme heat and cold.
“The gene helps the fungus to balance the internal salt content of the cell through the production of the alcohol glycerol and thus prevents the fungus from drying out and helps it defend itself against salinity,” said Nevo.
“I expected the gene transformation to increase the salt tolerance of the yeast. But the tolerance to high and low temperatures proved to be a surprise,” he added.
The results of the study were published in the Proceedings of the National Academy of Sciences [PNAS] of the United States. It was another feather in the cap of the institute, which Nevo founded in the mid-1970s.
Consisting of 25 research laboratories, the University of Haifa facility covers all aspects of evolutionary biology, from ecological modeling and ecological-genetics, to molecular evolution and cytogenetics, associated with the twin evolutionary processes of speciation and adaptation? and everything about evolution from bacteria to humans.
“We cut across the life spectrum,” Nevo said with a laugh.
A foreign associate of the National Academy of Scientists in the US, Nevo began his career as a geologist, but switched to the field of dynamic evolutionary biology in 1964.
“Even as a child, I was interested in this. I’m a born naturalist.”
Today the Institute of Evolution also hosts an international graduate center of evolution, which currently houses 70 PhD students from 10 countries, including Yan Jin from China.
“We also have another unit with 80 masters students and 1,300 undergraduates. We have collaborations with 500 labs in over 50 countries. Essentially we investigate all the problems connected to evolutionary biology, both theoretical and applicative,” said Nevo, with no small amount of pride.
Having devoted 30 years of his life to building the institute into a world-class center of learning, Nevo has no intentions of slowing down, and he’s as enthusiastic as a 20-year-old about the salinity gene research
“I’ve got no plans to retire ? on the contrary, I plan to continue onward,” he said.
Since the study was published, Nevo said that the team has gone a step further by also transferred the gene into the model plants Arabi-dopsis ?and have succeeded in making it salt-resistant.
“The genetic salt resistant resources of the Dead Sea could be very important for revolutionizing saline agriculture around the world. If we can transform this gene and other genes we’ve cloned, we’ll be able to improve crop production by making them salt tolerant and enable the growth of crops like wheat in a tepid desert area. Our goal is to develop a battery of salt resistant genes to be used for crop improvement.”
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