bad wheat

Gene keeps wheat from sprouting on the stalk

A new way to keep high humidity from damaging wheat crops could save farmers millions of dollars and even lead to better beer, say researchers.

The global wheat industry can lose up to $1 billion a year from grains that germinate in humid conditions before they are fully mature. The result is both a lower yield of wheat and grains of inferior quality. This phenomenon, pre-harvest sprouting or PHS, has such important economic repercussions for farmers around the world that scientists have been working on finding a solution to the problem for decades.

Their focus has been on genetic factors and on the interaction between genotypes and the environment as they have tried to breed wheat that is resistant to PHS, but with little success so far.

But now, findings published in the journal PLOS ONE, suggest that the solution may lie not with genetics alone, but rather with a combination of genetic and epigenetic factors.

A team of researchers, led by Professor Jaswinder Singh of McGill University’s Department of Plant Science, has identified a key gene that acts as a switch to determine how a particular plant will respond to high humidity and excess rainfall by either germinating early (PHS) or not. This switch is found in a key gene, ARGONAUTE4_9, in the “RNA dependent DNA Methylation” pathway (RdDM).

“The complex RdDM machinery is composed of several proteins that guide the genome in response to growth, developmental, and stress signals. It’s a bit like the plant’s brain,” says Singh. “Although in the past scientists have identified it as the pathway that regulates the way a variety of genes are expressed, until now no one had made the link with PHS.”

The researchers made the discovery by using a variety of genomic and molecular tools to identify specific ARGONAUTE4_­9 genes, and then compared the way that these genes are expressed in PHS resistant versus PHS susceptible varieties of wheat.

“This discovery is important for other cereals like barley as well as for wheat,” says Surinder Singh, a doctoral student and one of the authors of the study, currently working in Professor Singh’s laboratory. “This means that not only should we be able to avoid the ugly bread and sticky crumbs produced by PHS wheat in future, we should also end up with better beer.”

The research opens up a whole new area of exploration for scientists as they try to increase the yields of wheat and decrease losses due to excessively humid conditions. It should also save farmers and governments around the world significant amounts of money in the future.

The Natural Sciences and Engineering Research Council of Canada funded the study.

Source: McGill University