Plant positive single stranded RNA viruses induced vesicles are crucial for viral infection, replication, and spread. However, the mechanisms underlying negative single stranded RNA viruses induced vesicle biogenesis remain largely unknown. Here, a negative single stranded RNA virus, tomato spotted wilt orthotospovirus (TSWV) which is a representative member of genus Orthotospovirus in the Tospoviridae family, was used as a model to investigate the mechanisms involving the interaction between the viral and the host plant proteins in vesicle formation and function. We reported that the nonstructural protein (NSm) of TSWV, could induce endoplasmic reticulum (ER) - derived pathological vesicle biogenesis. In addition, NSm might hijack the host immunity proteins of NtPOX1 (a peroxidase) and pathogenesis-related protein NtPR-4A to form a potential tetrameric protein complex with Sar1 (a small GTPase), which was crucial for NSm-induced vesicle biogenesis. The results also revealed that these ER-derived pathological vesicles provided sites for TSWV replication. These findings provide novel and robust insights for understanding the infection processes and mechanisms of plant negative single stranded RNA viruses.

Previous studies indicated that ectomycorrhizal (EM) hyphae can access non-host plant roots and inhibit their growth, with the underlying mechanisms remaining largely unexplored. This study established a tripartite co-culture system consisting of EM fungi supported Quercus mongolica and non-host plants Arabidopsis thaliana or Setaria italica. Plant growth, nutrient concentrations, transcriptome (mRNAs and miRNAs), microbial communities, and fatty acids were determined to comprehensively understand the effects of EM on non-host plants. The results showed that roots of non-host plants were colonized by EM hyphae of Scleroderma. EM hyphae colonization significantly inhibited non-host plant growth and decreased their leaf [N], but increased leaf [P] and leaf free fatty acid concentrations. A small amount of 15N was transferred from non-host to Q. mongolica leaves. Foliar N application alleviated EM hyphae inhibited non-host plant growth. EM hyphae colonization activated expression of genes associated with plant-pathogen interaction responses but suppressed those involved in photosynthesis in A. thaliana leaves. Our findings suggest that a growth-defense trade-off, in conjunction with a leaf N: P stoichiometric imbalance, explain the observed inhibition of non-host plant growth by EM hyphae. This study provides insights into ectomycorrhiza mediated host and non-host plants interaction, which is important for plant community establishment.