Global investment needed to tackle major wheat losses

Agronomist breeding new variety of wheat, experimenting with mineral fertilizers

Urgent investment in new research is needed to help prevent huge yield losses from the world’s wheat crops, say scientists.

Global losses from wheat are worth some £22bn per year, according to scientists at the John Innes Centre, Norwich. They are calling for a major research project to reduce the impact of major wheat pathogens and improve global food security.

The scientists say an internationally coordinated approach could deliver a new ‘R-gene Atlas’. This would help identify new genetic solutions conferring disease resistance for crops that could be bred into commercial wheat varieties.

One fifth of the world’s potential wheat yield is lost annually to pests and pathogens – equivalent to some 209m tonnes of grain. Climate change could further disrupt global food chains as new types of pests and diseases increase their spread. 

Researchers say the broader use of disease resistance – which can be found in the genome of wheat and its wild relatives – could help to minimise these losses and reduce reliance on agrochemicals.

The aim is to provide long-lasting molecular protection against major pathogens such as rusts, blotch diseases and powdery mildew.

Wheat R-genes work by recognising corresponding molecules in the pathogen called effectors. By identifying the effectors present in pathogen and pest populations, more durable combinations or stacks of R-genes could be designed.

The R-gene Atlas will be a free online portal containing this genetic information and enabling breeders to design gene stacks using computer modelling before starting their breeding in the field.

Molecular markers

Scientists say this will enable users to design molecular markers that could be used to find out what resistance genes they already have – either in their breeding programmes or other wheat populations.

Recent years have seen researchers at the John Innes Centre and The Sainsbury Laboratory identify and clone resistance genes in wheat and its wild relatives using technologies such as AgRenSeq, MutRenSeq and MutChromSeq.

Molecular components involved in disease resistance – R genes and effectors – could be captured from both the host and pathogen. Whole genome sequencing would be carried out on wheat, its progenitors and domesticated and wild relatives.

Genetic variation

Association genetics, a method of seeking useful genetic variation, could then be used to look for correlations between the host genotype and disease resistance or susceptibility and the genes responsible for these traits could be identified.

The researchers calculate it would cost around £41m to establish the new platform at the required scale. But they say this is a minor investment considering the financial losses currently caused by wheat diseases.

“Compared to the scale of the problem in yield losses to pests and pathogens, this represents excellent value for money,” says first author Amber Hafeez.

“It is unsustainable to continue losing 20% of our wheat production to pathogens. Our enterprise applies cutting edge science to a global challenge that is increasing due to the climate emergency.”

Global population

Current projections suggest disease-resistant crops will be key to feeding a global population forecast to increase by 2.1bn people by 2050. But the scientists say resistant crops won’t be developed without investment.

“We have been delighted with the initial enthusiastic response to our proposals – many research groups and collaborators have welcomed the idea and we feel this confirms our belief that the time is right for this proposal.”