Plant mRNAs move into a fungal pathogen via extracellular vesicles to reduce infection

Area of Science:

• Plant-pathogen interactions
• RNA biology
• Molecular plant pathology

Background:

• Cross-kingdom RNA trafficking, particularly small RNAs, influences host-microbe interactions.
• The transfer of other RNA types, such as messenger RNAs (mRNAs), between plants and fungi remains largely unexplored.

Purpose of the Study:

• To investigate the potential transfer of host plant mRNAs into fungal pathogens.
• To determine if these transferred mRNAs are functional and impact the infection process.

Main Methods:

• Utilized a fluorescent RNA aptamer reporter system (Broccoli) to visualize host mRNAs in extracellular vesicles (EVs) and fungal cells.
• Employed translating ribosome affinity purification (TRAP) profiling and polysome analysis to assess mRNA translation in recipient fungal cells.
• Conducted ectopic expression studies in Botrytis cinerea and analyzed Arabidopsis knockout mutants.

Main Results:

• Demonstrated that Arabidopsis thaliana delivers mRNAs into the fungal pathogen Botrytis cinerea via EVs.
• Confirmed that these transferred host mRNAs are translated within fungal cells.
• Showed that ectopic expression of transferred mRNAs in B. cinerea proteins are detrimental to infection, and corresponding Arabidopsis mutants are more susceptible.

Conclusions:

• Plants possess a mechanism to combat fungal infections by transporting functional mRNAs into pathogenic fungi.
• This mRNA transfer compromises fungal infection, highlighting a novel plant defense strategy.
• Findings provide insights into inter-kingdom RNA communication and offer potential avenues for developing crop disease resistance.