Researchers on the University of Cologne's CEPLAS Cluster of Excellence on Plant Sciences have identified two fungal enzymes that hijack the plant's immune system, which play a vital role within the colonization of plant roots. These findings open up recent avenues of intervention in each medicine and agriculture/publication.
In nature, plant roots are all the time colonized by fungi. This interaction will be either mutualistic, benefiting each the plant and the fungus, or pathogenic, where the fungus harms the host plant. A research group on the CEPLAS Cluster of Excellence led by Prof. Dr. Alga Zucaro has now explained how helpful root fungi successfully colonize the roots of model plant plants. Initially, the fungus colonizes living root cells. Subsequently, limited cell death is triggered within the host plant, facilitating successful colonization without significant damage. The mechanisms controlling this host cell death are largely unknown. The team has now discovered that it encodes two enzymes, NucA and E5NT, that produce the molecule deoxyadenosine (dAdo). This molecule regulates cell death in plants, allowing the fungus to colonize the foundation system. This study shows that a nucleoside signal produced by a fungal endophyte regulates host cell death and promotes root colonization'.
The researchers found that dAdo is initially produced within the apoplast, a cell compartment outside host cells. In a subsequent step, dAdo enters the plant cell via the membrane transporter ENT3, where it hijacks the host's immune system and induces cell death. This phenomenon, as Professor Zuccaro's team has described, shouldn't be limited to plants. The same process occurs in human patients through the interaction between pathogenic bacteria and human immune cells.
'We found that helpful root fungi use two enzymes to provide dAdo, each to induce cell death and to enable successful colonization. This shows that the mechanism is conserved across different microbes and lifestyles,' said Professor Alga Zucaro. The results indicate essential interactions between microbial colonization and host immune metabolism, paving the way in which for brand spanking new strategies in medicine and agriculture. 'By understanding these shared mechanisms, we are able to develop more practical ways to administer each harmful and helpful microbes in human health and crop production.'