Exploring the Mycovirus Universe: Identification, Diversity, and Biotechnological Applications

Abstract

Viruses that infect fungi are known as mycoviruses and are characterized by the lack of an extracellular phase. In recent years, the advances on nucleic acids sequencing technologies have led to a considerable increase in the number of fungi-infecting viral species described in the literature, with a special interest in assessing potential applications as fungal biocontrol agents. In the present study, we performed a comprehensive review using Scopus, Web of Science, and PubMed databases to mine mycoviruses data to explore their molecular features and their use in biotechnology. Our results showed the existence of 267 mycovirus species, of which 189 are recognized by the International Committee on Taxonomy of Viruses (ICTV). The majority of the mycoviruses identified have a dsRNA genome (38.6%), whereas the Botourmiaviridae (ssRNA+) alone represents 14% of all mycoviruses diversity. Regarding fungal hosts, members from the Sclerotinicaeae appeared as the most common species described to be infected by mycoviruses, with 16 different viral families identified so far. It is noteworthy that such results are directly associated with the high number of studies and strategies used to investigate the presence of viruses in members of the Sclerotinicaeae family. The knowledge about replication strategy and possible impact on fungi biology is available for only a small fraction of the mycoviruses studied, which is the main limitation for considering these elements potential targets for biotechnological applications. Altogether, our investigation allowed us to summarize the general characteristics of mycoviruses and their hosts, the consequences, and the implications of this knowledge on mycovirus–fungi interactions, providing an important source of information for future studies.

Characterization of the RNA Mycovirome Associated with Grapevine Fungal Pathogens: Analysis of Mycovirus Distribution and Their Genetic Variability within a Collection of Botryosphaeriaceae Isolates

“…Two isolates of S. viticola and a single isolate of D. intermedia were found to be virus-free, as well as some D. seriata isolates (3/4), N. parvum (2/3), and D. mutila (1/4). Due to the dsRNA-based HTS strategy we followed, we cannot exclude the possibility that some DNA viruses, known to be more difficult to detect using this technique, could infect those isolates, even if there seem to be only very few DNA viruses infecting fungi so far [ 22 ]. The remaining six mycelia analyzed were found to be infected by a total of eight mycoviruses.…”

“…With the aim of developing biocontrol strategies using mycoviruses, many studies have so far focused on analyzing fungal isolates with strong hypovirulent phenotypes (for review, see [ 20 , 22 ]), without considering the whole mycovirome. Some elements highlighted in our study, such as the coinfection rate and the potential for cross-species transmission, should lead us to take caution since, as already pointed out by some authors [ 74 , 83 ], the outcome of the interactions between host and mycoviruses, and even between mycoviruses themselves during coinfections, still carry significant unpredictability.…”

“…HTS studies have shown mycoviruses to be widespread within the fungal kingdom. According to recent taxonomic advances, there are currently more than 250 recognized mycovirus species [ 22 , 23 ], and this number is rapidly growing. Most mycoviruses are positive-sense, single-stranded RNA (+ssRNA) or double-stranded RNA (dsRNA) viruses, although a few negative-sense single-stranded RNA (-ssRNA) and single-stranded DNA (ssDNA) viruses have also been described (for review, see [ 24 ]).…”

“…Most mycoviruses are positive-sense, single-stranded RNA (+ssRNA) or double-stranded RNA (dsRNA) viruses, although a few negative-sense single-stranded RNA (-ssRNA) and single-stranded DNA (ssDNA) viruses have also been described (for review, see [ 24 ]). Regarding fungal hosts, most mycoviruses have been identified from the Sclerotiniaceae family [ 22 ]. Considering the grapevine-associated Botryosphaeriaceae species, mycovirus screening has been mainly conducted in B. dothidea , probably because this fungus represents one of the most economically important phytopathogenic fungi worldwide, with a broad host range, including fruit trees and grapevine [ 2 ].…”

The Interaction between Hypovirulence-Associated Chrysoviruses and Their Host Fusarium Species

“…However, using chemicals has led to the development of fungal resistance, caused increased damage to natural ecosystems, and resulted in the accumulation of toxic residues; therefore, safer alternatives, such as the use of biological control agents, have been explored. Mycoviruses, the specialized parasites that proliferate in fungi and result in decreased or no virulence of the host fungi, are considered one of the most promising biocontrol agents [ 8 ]. Among them, host hypovirulence-related species of the Chrysoviridae family have the potential to be developed as biocontrol agents against Fusarium .…”