Search for: All records

Evidence shows that RNA trafficking is a key communication mechanism across kingdoms and species, but how RNAs are secreted and trafficked and how they function within the recipient organisms remain unclear. Here, we discuss how understanding inter-organismal RNA communication can assist in disease management in both agriculture and medicine. 

Abstract Small RNAs (sRNAs) of the fungal pathogenBotrytis cinereacan enter plant cells and hijack host Argonaute protein 1 (AGO1) to silence host immunity genes. However, the mechanism by which these fungal sRNAs are secreted and enter host cells remains unclear. Here, we demonstrate thatB. cinereautilizes extracellular vesicles (EVs) to secrete Bc-sRNAs, which are then internalized by plant cells through clathrin-mediated endocytosis (CME). TheB. cinereatetraspanin protein, Punchless 1 (BcPLS1), serves as an EV biomarker and plays an essential role in fungal pathogenicity. We observe numerousArabidopsisclathrin-coated vesicles (CCVs) aroundB. cinereainfection sites and the colocalization ofB. cinereaEV marker BcPLS1 andArabidopsis CLATHRIN LIGHT CHAIN 1, one of the core components of CCV. Meanwhile, BcPLS1 and theB. cinerea-secreted sRNAs are detected in purified CCVs after infection.Arabidopsisknockout mutants and inducible dominant-negative mutants of key components of the CME pathway exhibit increased resistance toB. cinereainfection. Furthermore, Bc-sRNA loading intoArabidopsisAGO1 and host target gene suppression are attenuated in those CME mutants. Together, our results demonstrate that fungi secrete sRNAs via EVs, which then enter host plant cells mainly through CME. 

Extracellular vesicles (EVs) are membrane-enclosed nanometer-scale particles that transport biological materials such as RNAs, proteins, and metabolites. EVs have been discovered in nearly all kingdoms of life as a form of cellular communication across different cells and between interacting organisms. EV research has primarily focused on EV-mediated intra-organismal transport in mammals, which has led to the characterization of a plethora of EV contents from diverse cell types with distinct and impactful physiological effects. In contrast, research into EV-mediated transport in plants has focused on inter-organismal interactions between plants and interacting microbes. However, the overall molecular content and functions of plant and microbial EVs remain largely unknown. Recent studies into the plant-pathogen interface have demonstrated that plants produce and secrete EVs that transport small RNAs into pathogen cells to silence virulence-related genes. Plant-interacting microbes such as bacteria and fungi also secrete EVs which transport proteins, metabolites, and potentially RNAs into plant cells to enhance their virulence. This review will focus on recent advances in EV-mediated communications in plant-pathogen interactions compared to the current state of knowledge of mammalian EV capabilities and highlight the role of EVs in cross-kingdom RNA interference. 

Abstract The study of RNAs has become one of the most influential research fields in contemporary biology and biomedicine. In the last few years, new sequencing technologies have produced an explosion of new and exciting discoveries in the field but have also given rise to many open questions. Defining these questions, together with old, long-standing gaps in our knowledge, is the spirit of this article. The breadth of topics within RNA biology research is vast, and every aspect of the biology of these molecules contains countless exciting open questions. Here, we asked 12 groups to discuss their most compelling question among some plant RNA biology topics. The following vignettes cover RNA alternative splicing; RNA dynamics; RNA translation; RNA structures; R-loops; epitranscriptomics; long non-coding RNAs; small RNA production and their functions in crops; small RNAs during gametogenesis and in cross-kingdom RNA interference; and RNA-directed DNA methylation. In each section, we will present the current state-of-the-art in plant RNA biology research before asking the questions that will surely motivate future discoveries in the field. We hope this article will spark a debate about the future perspective on RNA biology and provoke novel reflections in the reader. 

Communication between plant cells and interacting microorganisms requires the secretion and uptake of functional molecules to and from the extracellular environment and is essential for the survival of both plants and their pathogens. Extracellular vesicles (EVs) are lipid bilayer–enclosed spheres that deliver RNA, protein, and metabolite cargos from donor to recipient cells and participate in many cellular processes. Emerging evidencehas shown that both plant and microbial EVs play important roles in cross-kingdom molecular exchange between hosts and interacting microbes to modulate host immunity and pathogen virulence. Recent studies revealed that plant EVs function as a defense system by encasing and delivering small RNAs (sRNAs) into pathogens, thereby mediating cross-species and cross-kingdom RNA interference to silence virulence-related genes. This review focuses on the latest advances in our understanding of plant and microbial EVs and their roles in transporting regulatory molecules, especially sRNAs, between hosts and pathogens. EV biogenesis and secretion are also discussed, as EV function relies on these important processes.