"The groundwork of all happiness is health." - Leigh Hunt

A blessing in disguise: Mycoviruses enhance fungicide effectiveness against plant pathogens

As harmful as viruses could be, they could be helpful to farmers relating to coping with plant pathogens.

Osaka Metropolitan University scientists have discovered that a mycovirus that infects the plant pathogenic oomycete can increase the latter's sensitivity to certain fungicides. Their findings may result in modern methods for controlling plant diseases, reducing reliance on chemical treatments, and reducing agricultural losses.

Their results were published on May 3.

Mycoviruses, or fungal viruses, infect fungi in addition to fungus-like organisms similar to oomycetes. More commonly often known as water molds, oomycetes include among the most destructive plant pathogens and pose serious threats to global food security. When these oomycetes are infected with certain mycoviruses, nevertheless, their ability to cause disease could also be impaired — a phenomenon often known as hypovirulence — making mycoviruses potential biocontrol agents.

Mycoviral infections are multifactorial; They can reduce or increase the virus or remain hidden without obvious symptoms. Despite the growing variety of recently identified mycoviruses, their effects on host oomycetes remain largely unexplored.

“Since mycoviruses can significantly affect the ecology of oomycetes, we studied their effects at both the phenotypic and gene expression levels,” said Tomofumi Mochizuki, an associate professor at Osaka Metropolitan University's Graduate School of Agriculture. It felt obligatory to do.” This research.

The research team identified a big soil-borne oomycete answerable for damping off and root rot in lots of plant species. They first created a virus-free isogenic strain by high-temperature cultivation after which compared its properties and gene expression to that of a virus-infected isogenic strain.

The results showed that in comparison with the virus-free isogenic strain, the virus-infected isogenic strain was more prone to metalaxyl, one among the 4 tested fungicides. No significant differences in growth rate and structure were observed between these isogenic strains within the absence of metaxil. Using a high-throughput screening technique called RNA-seq to investigate gene expression profiles, the researchers found that isogenic strains infected with the virus had reduced expression of certain genes called ABC-type transporters, that are fungicides. Known to contribute to resistance.

“Our results show that mycoviral infections change the susceptibility of the host oomycete to fungicides,” said Aika Higuchi, a master's student and first writer of the study.

These findings advance the present understanding of the role of mycoviruses and their potential for sustainable agriculture. The team plans to further explore the promise of mycovirus as a biological control tool in quite a lot of species and environmental conditions.

“Our research shows that the effects of viral infection on the host oomycete can only be observed under certain conditions,” Mochizuki said. “Although at first glance it may seem that viral infection has no effect, it is important to analyze it from different angles.”