Journal Article

Virus-mediated suppression of host non-self recognition facilitates horizontal transmission of heterologous viruses

Fu, Yanping, Wu, Songsong, Ghabrial, Said A., Cheng, Jiasen, Chen, Tao, Xie, Jiatao, Jiang, Daohong

2017

Overview

Non-self recognition is a common phenomenon among organisms; it often leads to innate immunity to prevent the invasion of parasites and maintain the genetic polymorphism of organisms. Fungal vegetative incompatibility is a type of non-self recognition which often induces programmed cell death (PCD) and restricts the spread of molecular parasites. It is not clearly known whether virus infection could attenuate non-self recognition among host individuals to facilitate its spread. Here, we report that a hypovirulence-associated mycoreovirus, named Sclerotinia sclerotiorum mycoreovirus 4 (SsMYRV4), could suppress host non-self recognition and facilitate horizontal transmission of heterologous viruses. We found that cell death in intermingled colony regions between SsMYRV4-infected Sclerotinia sclerotiorum strain and other tested vegetatively incompatible strains was markedly reduced and inhibition barrage lines were not clearly observed. Vegetative incompatibility, which involves Heterotrimeric guanine nucleotide-binding proteins (G proteins) signaling pathway, is controlled by specific loci termed het (heterokaryon incompatibility) loci. Reactive oxygen species (ROS) plays a key role in vegetative incompatibility-mediated PCD. The expression of G protein subunit genes, het genes, and ROS-related genes were significantly down-regulated, and cellular production of ROS was suppressed in the presence of SsMYRV4. Furthermore, SsMYRV4-infected strain could easily accept other viruses through hyphal contact and these viruses could be efficiently transmitted from SsMYRV4-infected strain to other vegetatively incompatible individuals. Thus, we concluded that SsMYRV4 is capable of suppressing host non-self recognition and facilitating heterologous viruses transmission among host individuals. These findings may enhance our understanding of virus ecology, and provide a potential strategy to utilize hypovirulence-associated mycoviruses to control fungal diseases.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Agriculture / Agronomy / Airborne microorganisms / Analysis / Apoptosis / Ascomycota - virology / Attenuation / Bacteria / Barley / Biological evolution / Biology and Life Sciences / Cell death / Cell interactions / Data acquisition / Data collection / Data processing / Defensive behavior / Deoxyribonucleic acid / Disease transmission / Disease Transmission, Infectious / DNA / DNA Fingerprinting / Ecology / Evolutionary genetics / Fungi / Gene expression / Genetic aspects / Genetic polymorphisms / Genetics / Genomes / Host-virus relationships / Immune system / Inbreeding / Infections / Inhibition / Innate immunity / Laboratories / Medicine and Health Sciences / Microbiology / Mildew / Mimicry / Mortality / NAD(P)H oxidase / Nucleotide sequence / Papillae / Parasites / Pathogens / Pathology / Plant pathology / Plant sciences / Pollen / Polymerase Chain Reaction / Polymorphism / Position (location) / Proteins / Public concern / Reactive oxygen species / Recognition / Reoviridae - immunology / Reoviridae - pathogenicity / Reoviridae - ultrastructure / Reoviridae Infections - transmission / Reoviruses / Ribonucleic acid / RNA / Self-recognition / Signal transduction / Symbiosis / Technology / Transplantation / Viruses