Life of Giant Phages

Introduction

Bacterial viruses, phages, are ubiquitous and the most numerous entities in the biosphere. The development of sequencing techniques has increased our understanding of the diversity of phages that have not been isolated due to a lack of cultivable hosts and/or suitable isolation methods.

Viral Diversity and Challenges

While sequence data enables a better view of viral diversity, the lack of functional data and biological connections increases. Recently, different studies have found megaphages (mainly phages with a genome over 600 kbp) by assembling metagenomes from various environmental samples. However, no such isolates have been obtained thus far, meaning that their characteristics and host interactions are completely unknown.

Project Objectives

In this ERC project, I will enlighten the life of giant phages, a term I coined for both jumbo and megaphages. I will achieve this by using the first megaphage isolates that I have isolated from boreal freshwaters.

Research Focus

During the project, evidence on the following will be provided:

1. The megaphage structure
2. Host interactions
3. Symbiotic relationships with hosts

Using a unique set of different phage sizes infecting the same host, I will determine the size correlation to different life history traits.

Insights and Implications

I will provide insight into the mutualistic relationship between bacteria and their viruses and reveal new mechanisms behind phage competition. Additionally, I will determine the environmental preferences for megaphage emergence and abundance in boreal freshwaters.

Research Questions

In this proposal, I aim to understand:

• How megaphages are isolated
• Where megaphages are found
• When megaphages emerge

Consequently, results will aid in understanding the role of megaphages in other environments, such as the gut microbiome, and potentially provide avenues for developing new genetic tools.

Conclusion

This project will open new understanding for microbial ecology, especially phage ecology, and will create a new field of study under phage biology.