The fungus responsible for coffee wilt disease has been shown to frequently acquire DNA segments from a similar fungal pathogen, leading to ongoing outbreaks of this illness, as stated in a recent report.
The fungus responsible for coffee wilt disease has been shown to frequently acquire DNA segments from a similar fungal pathogen, leading to ongoing outbreaks of this illness. Lily Peck from Imperial College London, UK, shares these new insights in a study published on December 5 in the open-access journal PLOS Biology.
Over the last century, coffee wilt disease, caused by the fungus Fusarium xylarioides, has drastically affected coffee production in sub-Saharan Africa. Although it was first identified in 1927, there is still limited knowledge about the pathogen’s genetic makeup and evolutionary path, which is essential for controlling future outbreaks.
In this latest study, researchers examined the genomes of 13 historical strains collected over six decades and through various outbreaks to explore how the pathogen has changed and adjusted to its coffee host plants. They discovered that F. xylarioides consists of at least four different lineages: one that specifically targets arabica coffee, another that is tailored to robusta coffee, and two historical lineages that impacted various coffee species. The study also revealed that these strains had often incorporated genetic material from another fungal pathogen, F. oxysporum, which improved F. xylarioides‘s capacity to infect coffee plants. This process, known as horizontal gene transfer, likely played a significant role in the recurring outbreaks of coffee wilt disease across Africa.
Prior research has demonstrated that similar horizontal gene transfer occurrences have contributed to new outbreaks of various pathogens, including those causing potato blight, certain wheat fungi, and Aspergillus fumigatus, a fungus that typically affects people with weakened immune systems. The researchers concluded that utilizing genomic techniques on past fungal strains collected over the past century and preserved in culture collections could provide valuable insights into the impact of horizontal gene transfer on fungal outbreaks.
The authors remarked, “An examination of historical data highlights the significance of horizontal gene transfers and large mobile elements in the rise of new diseases. If we understand how novel diseases develop, we can equip farmers with the information needed to minimize the risk of new disease emergence.”
