Scientists from the Australian Centre for Plant Functional Genomics (ACPFG) produced GM rice, which has up to four times more iron and twice the levels of zinc than conventional rice, by modifying the genes of the rice to increase the amount of nutrients transported to the edible endosperm of the rice grain.
The researchers said that their GM rice represents the first time a rice lines has been reported with iron levels at, or higher than, the daily recommended levels.
“Rice is the primary source of food for roughly half of the world’s population, particularly in developing countries, yet the polished grain, also known as white rice, contains insufficient concentrations of iron, zinc and pro-vitamin A to meet daily nutritional requirements” said Dr Alex Johnson from ACPFG.
“A lack of genetic variation in rice has hindered efforts by conventional breeding programs to address iron levels. These programs have not been able to achieve the level of iron and zinc in the rice grain that we are able to achieve with a biotech approach in our glasshouse experiments,” he added.
The research, funded by the Australian Research Council and HarvestPlus, was in the journal PLoS ONE.
According to the World Health Organisation, iron deficiency is the most common and widespread nutritional disorder in the world and affects more than two billion people (30% of the world’s population).
“The development of new cereal varieties containing increased concentrations of iron and other essential micronutrients, an approach known as biofortification, offers an inexpensive and sustainable solution to the chronic micronutrient malnutrition problems that currently plague people in developing countries,” said Johnson.
The researchers genetically modified three populations of rice, to constitutively overexpress the gene loci OsNAS1, OsNAS2 orOsNAS3, respectively.
The team found that nicotianamine, iron and zinc concentrations were “significantly increased in unpolished grain of all three of the overexpression populations, relative to controls, with the highest concentrations in the OsNAS2 and OsNAS3 overexpression populations.”
A four-fold increase in iron and two-fold increase in zinc concentrations were reported in the OsNAS2population.
“The results demonstrate that rice cultivars overexpressing single rice OsNASgenes could provide a sustainable and genetically simple solution to iron and zinc deficiency disorders affecting billions of people throughout the world,” said Johnson and his colleagues.
The team is said to be the first to raise rice plants in the greenhouse with the desired level of iron and zinc. They said that field trials for the rice strain have already begun in the Philippines – in collaboration with the International Rice Research Institute.
However, Johnson and his team noted that it will take several seasons to determine whether the rice is growing properly and consistently taking up sufficient iron and zinc. Only then will they be able to test whether animals can actually obtain more nutrients from the grain, before eventually progressing to developing a product for human consumption.
Johnson said that he expects the entire process could take around a decade, explaining that it may be a while before iron-rich rice appears on supermarket shelves but adding that the research opens the door to a range of new and improved super foods.
Source: PLoS ONE
Published online ahead of print, doi: 10.1371/journal.pone.0024476
“Constitutive Overexpression of the OsNAS Gene Family Reveals Single-Gene Strategies for Effective Iron- and Zinc-Biofortification of Rice Endosperm”
Authors: A.A.T. Johnson, B. Kyriacou, D.L. Callahan, L. Carruthers, J. Stangoulis, E. Lombi, M. Teste