Proceedings of the National Academy of Sciences highlights

Atmospheric pollution correlates with the prevalence of wheat diseases caused by two fungal pathogens, researchers report.

Some agricultural diseases can suddenly appear or disappear, yet disease dynamics can rarely be analyzed due to lack of long-term data. To elucidate factors controlling wheat disease patterns in the United Kingdom, Bart Fraaije and colleagues measured the abundance of DNA for two fungal pathogens (Phaeosphaeria nodorum and Mycosphaerella graminicola) in wheat samples archived from a long-term experiment that began in 1843.

The scientists determined that the relative amounts of pathogen DNA correlated with national wheat disease trends. M. graminicola, the most abundant pathogen since the 1980s, was also prominent in the mid-1800s. In contrast, P. nodorum DNA was more common than M. graminicola for much of the 1900s, with a peak in about 1970. Unexpectedly, long-term changes in the ratio of the pathogens were strongly correlated with changes in air pollution, as measured by sulfur dioxide (SO2) emissions. When emissions were high, P. nodorum was abundant, while M. graminicola was scarce--indicating that SO2 differentially affected pathogen growth or impaired plant disease resistance.

The researchers suggest that similar research could assess how the changing environment impacts biodiversity and possibly predict disease outbreaks.

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