Historical samples link wheat disease to air pollution
19 Apr 2005 by Evoluted New Media
Scientists at have been able to recover DNA from crop diseases on wheat samples stored as part of a Victorian field experiment.
Scientists at have been able to recover DNA from crop diseases on wheat samples stored as part of a Victorian field experiment.
Scientists at Rothamsted Research and the University of Reading have been able to recover DNA from crop diseases on wheat samples stored as part of a Victorian field experiment. Using this DNA, they have discovered how changes in air pollution over the last 160 years have affected fungal diseases on our wheat crops.
The most damaging wheat disease in Europe is leaf blotch, caused by two different fungal species, Phaeosphaeria nodorum and Mycosphaerella graminicola. These species cause the loss of millions of tonnes of grain worldwide each year. Changes in the importance of these two species have been reported in the UK and elsewhere but the reason for this has remained unclear.
Dr Bart Fraaije and his colleagues looked at straw samples archived from the Broadbalk experiment, the world's oldest, continually-running field experiment, set up in 1843 to investigate the effect of fertilisers on crop yields and the soil. They were able to extract fungal DNA from the straw, enabling them to carefully track changes in the populations of the two fungi since Broadbalk's inception over 160 years ago.
Their results show that changes in the relative abundance of the diseases are strongly linked to changes in the atmospheric emissions of sulphur dioxide (SO2). As SO2 emissions rose during and after the industrial revolution, P. nodorum became abundant, whilst M. graminicola was scarce. However, coal burning has declined dramatically over the past 20 years, leading to a decline in SO2 emissions and the situation is now reversed, with M. graminicola more common.
