TETRASPANIN 8-1 from Phaseolus vulgaris plays a key role during mutualistic interactions

Messenger and message: Uncovering the roles, rhythm and regulation of extracellular vesicles in plant biotic interactions

Extracellular vesicles (EVs) are membrane-delimited nanoparticles found in every kingdom of life and are known to mediate cell-cell communication in animal systems through the trafficking of proteins and nucleic acids. Research into plant and microbial EVs suggests that these have similar transport capacity, and moreover are able to mediate signalling not only within an organism but also between organisms, acting between plants and their microbial partners in cross-kingdom signalling. Here, we review recent research exploring the roles of these EVs, both plant and microbial, highlighting emerging trends of functional conservation between species and across kingdoms, complemented by the heterogeneity of EV subpopulations at the organism level that places EVs as powerful regulatory mechanisms in plant biotic interactions.

New insights into plasmodesmata: complex 'protoplasmic connecting threads'

Intercellular communication in plants, as in other multicellular organisms, allows cells in tissues to coordinate their responses for development and in response to environmental stimuli. Much of this communication is facilitated by plasmodesmata (PD), consisting of membranes and cytoplasm, that connect adjacent cells to each other. PD have long been viewed as passive conduits for the movement of a variety of metabolites and molecular cargoes, but this perception has been changing over the last two decades or so. Research from the last few years has revealed the importance of PD as signaling hubs and as crucial players in hormone signaling. The adoption of advanced biochemical approaches, molecular tools, and high-resolution imaging modalities has led to several recent breakthroughs in our understanding of the roles of PD, revealing the structural and regulatory complexity of these 'protoplasmic connecting threads'. We highlight several of these findings that we think well illustrate the current understanding of PD as functioning at the nexus of plant physiology, development, and acclimation to the environment.

Extracellular vesicles in plant-microbe interactions: Recent advances and future directions

Extracellular vesicles (EVs) are membrane-enclosed nanoparticles that have a crucial role in mediating intercellular communication in mammals by facilitating the transport of proteins and small RNAs. However, the study of plant EVs has been limited for a long time due to insufficient isolation and detection methods. Recent research has shown that both plants and plant pathogens can release EVs, which contain various bioactive molecules like proteins, metabolites, lipids, and small RNAs. These EVs play essential roles in plant-microbe interactions by transferring these bioactive molecules across different kingdoms. Additionally, it has been discovered that EVs may contribute to symbiotic communication between plants and pathogens. This review provides a comprehensive summary of the pivotal roles played by EVs in mediating interactions between plants and microbes, including pathogenic fungi, bacteria, viruses, and symbiotic pathogens. We highlight the potential of EVs in transferring immune signals between plant cells and facilitating the exchange of active substances between different species.