RNA-binding proteins contribute to small RNA loading in plant extracellular vesicles

• Published in: Nature plants Vol. 7; no. 3; pp. 342 - 352
• Main Authors: He, Baoye, Cai, Qiang, Qiao, Lulu, Huang, Chien-Yu, Wang, Shumei, Miao, Weili, Ha, Tommy, Wang, Yinsheng, Jin, Hailing
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2021; Nature Publishing Group
• Subjects: 14/1; 14/19; 45; 45/90; 631/449; 631/80; 82; 82/29; 82/58; 82/80; 82/83; Annexins; Annexins - metabolism; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Argonaute Proteins - metabolism; Binding; Biomedical and Life Sciences; Botrytis; DEAD-box RNA Helicases - metabolism; Extracellular vesicles; Extracellular Vesicles - metabolism; Fungi; Gene silencing; Genes; Life Sciences; Pathogens; Plant Diseases - genetics; Plant Diseases - immunology; Plant immunity; Plant Sciences; Proteins; Proteome; Regulators; Ribonucleic acid; RNA; RNA, Plant - metabolism; RNA, Small Interfering; RNA-binding protein; RNA-Binding Proteins - metabolism; RNA-mediated interference; Silence; Stabilization; Tetraspanins - metabolism; Vesicles; Virulence
• DOI: 10.1038/s41477-021-00863-8
• ISSN: 2055-0278

Plants use extracellular vesicles (EVs) to transport small RNAs (sRNAs) into their fungal pathogens and silence fungal virulence-related genes through a phenomenon called ‘cross-kingdom RNAi’. It remains unknown, however, how sRNAs are selectively loaded into EVs. Here, we identified several RNA-binding proteins in Arabidopsis , including Argonaute 1 (AGO1), RNA helicases (RHs) and annexins (ANNs), which are secreted by exosome-like EVs. AGO1, RH11 and RH37 selectively bind to EV-enriched sRNAs but not to non-EV-associated sRNAs, suggesting that they contribute to the selective loading of sRNAs into EVs. Conversely, ANN1 and ANN2 bind to sRNAs non-specifically. The ago1, rh11   rh37 and ann1   ann2 mutants showed reduced secretion of sRNAs in EVs, demonstrating that these RNA-binding proteins play an important role in sRNA loading and/or stabilization in EVs. Furthermore, rh11   rh37 and ann1   ann2 showed increased susceptibility to Botrytis cinerea , suggesting that RH11, RH37, ANN1 and ANN2 positively regulate plant immunity against B. cinerea . Plants use extracellular vesicles to deliver small RNAs that could silence fungal virulence genes to their fungal pathogens. In this study, the authors profile the components of these extracellular vesicles and investigate regulators contributing to the specific RNA loading and stabilization.