WORLD HUNGER

Super rice: newly discovered gene could massively improve rice yields, helping fight world hunger

PUBLISHED : Wednesday, 19 August, 2015, 7:00am
UPDATED : Wednesday, 19 August, 2015, 6:54pm

A newly discovered gene could increase rice production by up to a third, according to a study by Chinese scientists, potentially offering a new weapon in the fight against global hunger.

The United Nations estimates that currently around 795 million people worldwide are undernourished, or about one in nine people, and rice is an important source of nutrition for undeveloped countries.

By modifying the plant’s BG1 gene, the researchers said they were able to create one of the largest rice grains on the planet.

Strengthening the expression of BG1 could lead to a 33.8 per cent increase in weight per thousand grains, according to Li Jiayang and Chu Chengcai of the Chinese Academy of Sciences’ Institute of Genetics and Developmental Biology in Beijing.

The two main subspecies of rice are japonica and indica. Short-grained japonica varieties of rice are around 5mm in length and prevalent in Japan and northern Asia; while indica, long grain varieties are popular in Southeast Asia.

The genetically modified grain, based on japonica rice, grows to over 8mm in length, longer even than most “long grain” varieties. The grains are also far wider than current long grain rice, resulting in a subspecies that would dwarf all varieties on the market today in terms of mass.

Over the years, researchers had identified a number of genes they thought were linked to grain size and yield, but BG1 was different, the Chinese scientists said. It is the first grain-size regulating gene with hormone boosting capability, meaning it could increase the production of all existing rice subspecies. Other genes previously identified have often been limited in effectiveness to only one or two subspecies.    

BG1 controls the flow of auxin,  an important hormone that regulates plant growth and not only results in bigger grain size, but bulkier stalks and leaves as well, with up to an 18 per cent increase in dry plant weight.

The discovery of BG1 could also potentially be used to boost the production of other commercial agricultural plants, the scientists said.

The researchers said “considering that … BG1 exists in …  sorghum,  medicago,  maize and soybean, BG1 may have extensively practical roles in improving plant biomass and grain productivity”  they wrote in the paper.

But the study left some important questions unanswered. For instance, the exact mechanism of how the BG1 gene regulates plant hormone flow is not fully understood, and any possible negative side effect of the gene’s over-expression has not been explored.

The scientists also did not report the taste of the giant rice, skimming over the important point of whether the big grains would actually be pleasant to eat.

Their paper was published on Monday in the journal Proceedings of the National Academy of Sciences

In previous research, Chu claimed to have increase japonica’s rate of absorption of nitride, reducing the need for nitrogen fertilisers.