The fern Pteris vittata can tolerate 100 to 1,000 times more arsenic than other plants. Jody Banks, a professor of botany and plant pathology, and David Salt, a professor of horticulture, uncovered what may have been an evolutionary genetic event that creates an arsenic pump of sorts in the fern.
"It actually sucks the arsenic out of the soil and puts it in the fronds," Banks said. "It's the only multi-cellular organism that can do this."
Without a genome sequenced for Pteris vittata, Banks and Salt used a method of gene identification called yeast functional complementation. They combined thousands of different Pteris vittata genes into thousands of yeast cells that were missing a gene that makes them tolerant to arsenic.
The yeast was exposed to arsenic, with most of it dying. The yeast strains that lived had picked up the genes from Pteris vittata that convey arsenic resistance.
To confirm that this was the correct gene, its function was knocked down and the plant was exposed to arsenic. Without the gene functioning properly, the plant could not tolerate arsenic.
"It tells us that this gene is necessary for the plant to function on arsenic," said Banks, whose findings were published in the early online version of the journal Plant Cell. "We looked for a similar gene in the plant Arabidopsis. We couldn't find it. It can't be found in any flowering plant."
Banks and Salt found that the protein encoded by this gene ends up in the membrane of the plant cell's vacuole. Salt said the protein acts as a pump, moving arsenic into the cell's equivalent of a trashcan.
"It stores it away from the cytoplasm so that it can't have an effect on the plant," Salt said.
Banks said understanding how the Pteris vittata functions with arsenic could lead to ways to clean up arsenic-contaminated land.
"Potentially you could take these genes and put them in any organism that could suck the arsenic out of the soil," Banks said.
Salt said rice plants could be modified with the gene to store arsenic in the roots of plants - instead of rice grains - in contaminated paddies.
Banks and Salt found another gene in Pteris vittata that looks almost exactly the same as the one that controls arsenic tolerance. When the fern was exposed to arsenic, the confirmed arsenic-tolerance gene increased its expression while the similar gene did not.
Salt said the gene that regulates arsenic tolerance could be a duplicate of the other that has changed slightly to give itself a new function.
"The fact that it has these two genes could be a sign of evolution," Salt said. "One of the thoughts of gene evolution is that one copy could continue to do what it has always done, while the duplicate can develop another function."
The plant might have evolved to accumulate arsenic, Banks and Salt theorized, as a defense against animals or insects eating them.
Banks hopes findings such as this will lead to more research emphasis on non-flowering plants. She said there are characteristics in plants such as Pteris vittata that cannot be found in other organisms.
The next step in their research is to put the arsenic-tolerance gene from Pteris vittata into Arabidopsis to see whether it gives the new plant the same characteristics.
The National Science Foundation funded the research.
Abstract on the research in this release is available at: http://www.purdue.edu/newsroom/research/2010/100610BanksFern.html
Brian Wallheimer | EurekAlert!
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy