Taming wild genes to fight crop diseases

By Country News

A global alliance of researchers has pioneered a new method to rapidly recruit disease-resistance genes from wild plants for transfer into domestic crops.

The technique, called AgRenSeq, was developed by scientists at the John Innes Centre in Great Britain working with colleagues in Australia and the United States, and speeds up the fight against pathogens that threaten global food crops, including wheat, soyabean, maize and rice.

Professor Harbans Bariana from the Sydney Institute of Agriculture, a global expert in cereal rust genetics and a co-author of the paper, said the technology would fast-track discovery of new sources of disease resistance in plants.

The current research builds on previous collaborative work done by Prof Bariana with the CSIRO and John Innes Centre using two cloned wheat genes.

AgRenSeq lets researchers search a library of resistance genes discovered in wild relatives of modern crops so they can rapidly identify sequences associated with disease-fighting capability.

From there researchers can use laboratory techniques to clone the genes and introduce them into elite varieties of domestic crops to protect them against pathogens and pests such as rusts, powdery mildew and Hessian fly.

Dr Brande Wulff, a crop genetics project leader at the John Innes Centre and a lead author of the study, said the process took 10 or 15 years and was like ‘‘searching for a needle in a haystack’’.

‘‘We have perfected the method so that we can clone these genes in a matter of months and for just thousands of dollars instead of millions,’’ Dr Wulff said.

The research reveals AgRenSeq has been successfully trialled in a wild relative of wheat — with researchers identifying and cloning four resistance genes for the devastating stem rust pathogen in the space of months.

‘‘Our results demonstrate that AgRenSeq is a robust protocol for rapidly discovering resistance genes from a genetically diverse panel of a wild crop relative,’’ Dr Wulff said.

‘‘If we have an epidemic, we can go to our library and inoculate that pathogen across our diversity panel and pick out the resistance genes.

‘‘Using speed cloning and speed breeding we could deliver resistance genes into elite varieties within a couple of years, like a phoenix rising from the ashes.’’