Oomycete small RNAs invade the plant RNA-induced silencing complex for virulence

Dunker, F.; Trutzenberg, A.; Rothenpieler, J. S.; Kuhn, S.; Pröls, R.; Schreiber, T.; Tissier, A.; Hückelhoven, R.; Weiberg, A.

doi:10.1101/689190

bioRxiv · 10.1101/689190

Oomycete small RNAs invade the plant RNA-induced silencing complex for virulence

Dunker, F.·Trutzenberg, A.·Rothenpieler, J. S.·Kuhn, S.·Pröls, R.·Schreiber, T.·Tissier, A.·Hückelhoven, R.·Weiberg, A.

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Abstract

Fungal small RNAs (sRNAs) hijack the plant RNA silencing pathway to manipulate host gene expression, named cross-kingdom RNA interference (ckRNAi). It is currently unknown how conserved and significant ckRNAi is for microbial virulence. Here, we found for the first time that sRNAs of a pathogen representing the oomycete kingdom invade the host plants Argonaute (AGO)/RNA-induced silencing complex. To demonstrate the functionality of the plant-invading oomycete Hyaloperonospora arabidopsidis sRNAs (HpasRNAs), we designed a novel CRISPR endoribonuclease Csy4/GUS repressor reporter to visualize in situ pathogen-induced target suppression in Arabidopsis thaliana host plant. By using 5 RACE-PCR we demonstrated HpasRNAs-directed cleavage of plant mRNAs. The significant role of HpasRNAs together with AtAGO1 in virulence was demonstrated by plant atago1 mutants and by transgenic Arabidopsis expressing a target mimic to block HpasRNAs, that both exhibited enhanced resistance. Individual HpasRNA plant targets contributed to host immunity, as Arabidopsis gene knockout or HpasRNA-resistant gene versions exhibited quantitative enhanced or reduced susceptibility, respectively. Together with previous reports, we found that ckRNAi is conserved among oomycete and fungal pathogens.

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Dunker, F., Trutzenberg, A., Rothenpieler, J. S., Kuhn, S., Pröls, R., Schreiber, T., Tissier, A., Hückelhoven, R., Weiberg, A.. 2019-07-02. Oomycete small RNAs invade the plant RNA-induced silencing complex for virulence. https://doi.org/10.1101/689190

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