The role of extracellular small RNA (sRNA) in interkingdom communication between microorganisms and their eukaryotic hosts
has been revealed recently. Extracellular vesicles (EVs) are a significant delivery route of sRNAs, thus regulating gene expression
in the recipient cell. Such interactions have been shown between fungi and plants as well as bacteria and animals but, little is
known about sRNA-mediated host responses between bacteria and plants or fungi.

This project aims to study the role of sRNAs in the outer membrane vesicles (OMVs) of the plant growth promoting bacteria
(PGPB) (of genera Paraburkholderia, Pseudomonas and Enterobacter) in the naturally occurring communication with plant
(Arabidopsis thaliana) and phytopathogenic fungi (Botrytis cinerea). Further, we will explore the ability of engineered
OMV-sRNAs to manipulate fungal genes, as a means to suppress fungal diseases of plants.

To monitor the delivery of the OMV cargo into plant and fungi, OMVs and sRNAs will be fluorescently labeled and OMVs’
interaction with recipient cells, and RNA delivery, will be monitored by confocal microscopy. sRNA from OMVs and cells
of bacteria, grown separately or in the interaction with the plant or fungus, will be sequenced and compared to define the
criteria for the selection of sRNAs to be packed into OMVs. To identify sRNAs delivered by OMVs to recipient cells,
sRNA-Seq and bioinformatics analysis of plant and fungal cells upon exposure to bacteria will be performed. The ability
of OMV-sRNAs to modulate the expression of predicted target genes in the host cells will be tested both for endogenous
bacterial and engineered sRNAs, designed to target recipient’s gene(s).

The main expected results: the visualization of OMV cargo delivery to recipient cells; revealing the selection criteria for
sRNA packaging into OMVs; and evidence of OMV-sRNAs mediated regulation of host genes will be novel, ground-breaking
discoveries, impacting many research fields , from agriculture to medicine. The project will pave the way for using engineered
OMVs-sRNAs to modulate plant/fungal physiology, encouraging further studies of the application of this process in biocontrol
against phytopathogenic fungi, with a potential to its extrapolation to animal and human fungal pathogens.

CALL FOR APPLICATIONS
The exRNA-PATH COST Action CA20110 “RNA communication across kingdoms: new mechanisms and strategies in
pathogen control” is happy to announce that the first call is now open for Short Term Scientific Missions (STSMs) and
Inclusiveness Target Country (ITC) Conference grants.
STSM call: bit.ly/STSM-2022
ITC call: bit.ly/ITC-2022

COST action CA20110
SCIENCE FUND of the Republic of Serbia