Scientists, including Imperial College London, the University of Oxford and CABI, have 'turned up the warmth' on how repeated outbreaks of coffee wilt disease threaten the Arabica and Robusta varieties of our favourite on a regular basis coffee blends. is
The fungal pathogen poses a major threat to coffee production and income in sub-Saharan Africa, say scientists presenting their findings within the journal.
Their work supports earlier findings based on DNA markers and crossing experiments that suggested it’s a species complex with distinct, host-specific populations.
The scientists confirmed the existence of genetically distinct lineages for Arabica and Robusta coffee with different hosts and showed that the fungal pathogen repeatedly “horizontally transferred” segments of DNA from related fungal taxa that It played a crucial role within the successive outbreaks of the disease.
The primary source of income for over 12 million households
Coffee is a primary source of income for greater than 12 million households in Africa and a major contributor to tax revenue in a lot of these countries, with Ethiopia, for instance, recording an annual export value of $762.8 million. is Yet recurrent outbreaks of coffee wilt disease have continued to scale back coffee production in East and Central Africa for the reason that Twenties, affecting yields and farmers' incomes.
As a part of the study, the scientists compared the genomes of 13 historic strains spanning six many years from CABI's culture collection, to discover the evolutionary processes behind these recurrent outbreaks of coffee wilt disease.
Dr Matthew Ryan, Senior Research Lead, Biological Resources at CABI and co-author of the paper, with co-supervised lead writer of the research, Dr Lily Peck of Imperial College London, and Professor Tim Barclough of the University of Oxford.
Important for understanding genetic structure and evolutionary potential.
“To improve disease management of fungal pathogens, understanding their genetic makeup and evolutionary potential is critical,” said Dr. Peck.
“We found that there are at the very least 4 distinct lineages: one host-specific arabica, one robusta and two historical lineages isolated from different coffee cultivars.
“The presence/absence of large genomic regions in these lineages showed that horizontal transfer of effector genes, i.e., genes important in establishing successful infection, played an important role in establishing host specificity.”
Dr. Peck also noted that multiple translocations within the population corresponded to different parts of the mobile pathogenicity chromosome and were enriched in effector genes and transposons.
Transposons, also referred to as “jumping genes,” are DNA sequences that may move across the genome. They are present in many organisms including bacteria, yeast, humans, mice, fruit flies and frogs.
Highly expressed during infection by transcriptomics.
Effector genes and other carbohydrate-active enzymes vital within the breakdown of plant cell partitions have been shown by transcriptomics to be highly expressed during infection of Arabica coffee by pathogenic Arabica strains.
“The widespread sharing of specific transposons between and, and the correspondence of horizontally transferred regions (the recently identified large mobile elements involved in fungal horizontal gene transfer), horizontal reinforce the migration hypothesis and suggest that mobile elements were involved.
“Our results support the hypothesis that horizontal gene transfer contributed to the recurrent emergence of coffee wilt disease.”
Potentially profitable export of various varieties of coffee
Dr Ryan said the research findings potentially reveal what is occurring more broadly with fungi and provides scientists the power to construct on Dr Peck's study in the longer term.
“The fact that horizontal gene transfer contributes to the frequent emergence of a wilt disease between two different species is an important mechanism for understanding what is happening more broadly in the fungus — what To the extent, we just don't know,” he said.
The scientists consider that horizontal transmission may occur in 'common space', as each are soil-borne pathogens and have been isolated from the roots and wood of deciduous trees in Ethiopia and Central Africa. Banana tree in Central Africa.
Knowledge of horizontal transfer mechanisms and potential donor taxa will help design future intercropping strategies that reduce the chance of effector gene transfer between closely related taxa, they added.