Late blight strain HERB-1 has been isolated - a bacterium that changed history

For many years, potatoes were a real salvation from hunger for many poor Irish peasants. But in 1845-1849. it also became a disaster for them: tubers affected by late blight did not bear fruit, and famine claimed, according to various estimates, the lives of 0.5-1.5 million Irish people. The flow of migration increased, as a result the population decreased by a third - the very history of the country changed. It is believed that, in terms of demographics, Ireland has still not recovered from the shocks of more than a century and a half ago.

The culprit is tiny oomycete bacteria, the causative agents of late blight, the most common potato disease. Recently, scientists for the first time managed to decipher the genome of that harmful strain using plant samples from ancient herbariums. Despite the fact that they were dried 120 or even 170 years ago, they retained a lot of intact bacterial DNA - scientists are not without satisfaction that this has opened up a huge source of genetic information, which can become very valuable for population genetics research, microbiology, epidemiology.

Until now, it was believed that the cause of the Great Famine in Ireland was the oomycete Phytophthora infestans strain US-1, but genetic analysis discovered a completely new strain, previously unknown to science. Scientists believe that the evolutionary paths of HERB-1 and US-1 diverged shortly before the outbreak. HERB-1 emerged in the early 1800s and quickly spread throughout the world within a century. With the advent of new resistant potato varieties, it disappeared, replaced by the US-1 strain, but managed to leave a noticeable mark on history.