Cross-kingdom RNA interference in the Botrytis-plant interaction

Cheng, An-Po (2025): Cross-kingdom RNA interference in the Botrytis-plant interaction. Dissertation, LMU München: Fakultät für Biologie

Abstract

Cross-kingdom RNA interference (ckRNAi) represents a novel and rapidly advancing frontier in the study of host–pathogen interactions. In previous studies, it was shown that the fungal pathogen Botrytis cinerea (B. cinerea) could deliver small RNAs (sRNAs) into plant host cells. It was observed that the fungal sRNAs were able to hijack the plant RNAi machinery, which resulted in the suppression of immune-related gene expression and the promotion of infection (Wang et al., 2016; Weiberg et al., 2013). However, the fungal RNA interference (RNAi) components that mediate this cross-kingdom RNA trafficking have not yet been fully identified. Me and my colleague developed a novel GFP-based "switch-on" reporter system to monitor ckRNAi in real-time during infection. Based on this reporter tool, I identified key fungal components required for ckRNAi, including Botrytis RNA-dependent RNA polymerase 1 (BcRDR1), Argonaute 1 (BcAGO1), and Argonaute 2 (BcAGO2). BcRDR1 and BcAGO1 showed to be involved in the accumulation of B. cinerea sRNAs, while BcAGO2 is crucial for the translocation of these sRNAs into host cells. I confirmed our candidate fungal sRNAs, which derived from fungal transposon elements, mediated silencing of plant defense-related genes. Co-immunoprecipitation of BcAGOs and sRNA sequencing revealed a mutual RNA exchange, in which host-derived sRNAs are transported into fungal cells and loaded into BcAGOs. Functional analysis has demonstrated that these plant sRNAs have the capacity to suppress fungal virulence gene expression. My findings supported that ckRNAi is a bidirectional process that influenced both fungal pathogenicity and plant defense. My works offered a deeper insight into the significant roles of B. cinerea argonaute and RNA-dependent RNA polymerase proteins in ckRNAi. I provided molecular evidence that suggested the RNA-based bidirectional communication between fungal pathogens and their plant hosts. These insights could potentially broaden our understanding of RNA-mediated host–pathogen interactions and may suggest new avenues for RNAi-based disease management strategies in agriculture.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: cross-kingdom RNA interference, small RNA, plant–fungal interaction, RNA-dependent RNA polymerases, Argonaute
• Themengebiete: 500 Naturwissenschaften und Mathematik ; 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
• Fakultäten: Fakultät für Biologie
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 4. November 2025
• 1. Bericht­erstatter:in: Weiberg, Arne