The future of using cell-membrane transporters in plants to improve crops for sustainable food production was yesterday introduced at the National Science Council by Tsay Yi-fang (蔡宜芳), a research fellow at Academia Sinica’s Institute of Molecular Biology.
The perspectives she reported on were suggested by an international collaborative team, which included Tsay and 11 researchers from the US, UK, Australia, Mexico and Japan, in the latest issue of Nature magazine.
“The membrane is like a plastic bag wrapped around a plant’s cells, to block outside substances from affecting the cell. However, the cell needs to exchange substances with the outside environment, such as absorb nutrients and discharge waste, so it needs ‘holes’ in the ‘plastic bag,’ which are called transporters — a protein on the membrane [that lets certain substances through and blocks others],” Tsay said.
Tsay’s contribution to the report was mainly expanded from her discovery in 2009 of the transporter in charge of absorbing nitrates. It not only transfers nitrates into the cell, but also act as a “gatekeeper” by detecting the level of nitrates in the soil and transmitting the information to the cell’s “control center” — the nucleus.
“Knowing that the transporter has more than one function allows us to work on how to improve crops by modifying their transporters, such as improving a certain crop’s nitrates absorption rate. This in turn will reduce the amount of nitrogen-rich fertilizer used on those crops,” she said.
Although nitrogen-rich fertilizer contributed to the “green revolution” in agriculture by greatly improving crop yields, about 1 percent of the world’s energy is spent on manufacturing the fertilizer every year, Tsay said.
Moreover, only 30 percent to 50 percent of the fertilizer is absorbed by plants and the remaining fertilizer in the soil emits nitrous oxide into the air — a worse greenhouse gas than carbon dioxide — or is washed into bodies of water, causing eutrophication in rivers and oceans, she added.
Tsay said the research results from different researchers in the team all show the possibility of improving crops and agricultural land use, such as modifying crops to resist pests or grow in salty soil, and can help solve the increasing demand for food by the world’s growing population.
In response to concerns about the effects of genetically modified organisms on the environment and human health, Tsay said research has shown that land use can often be improved through using these organisms.
For example, a researcher in the team has used genetically modified organisms to improve the heavy-metal absorption rate of crops, which can help remove heavy metals from the soil, Tsay said, adding that there is no scientific evidence that these organisms are harmful to humans.