Mycelia-Assisted Isolation of Non-Host Bacteria Able to Co-Transport Phages

Abstract

Recent studies have demonstrated that phages can be co-transported with motile non-host bacteria, thereby enabling their invasion of biofilms and control of biofilm composition. Here, we developed a novel approach to isolate non-host bacteria able to co-transport phages from soil. It is based on the capability of phage-carrying non-host bacteria to move along mycelia out of soil and form colonies in plaques of their co-transported phages. The approach was tested using two model phages of differing surface hydrophobicity, i.e., hydrophobic Escherichia virus T4 (T4) and hydrophilic Pseudoalteromonas phage HS2 (HS2). The phages were mixed into soil and allowed to be transported by soil bacteria along the mycelia of Pythium ultimum. Five phage-carrying bacterial species were isolated (Viridibacillus sp., Enterobacter sp., Serratia sp., Bacillus sp., Janthinobacterium sp.). These bacteria exhibited phage adsorption efficiencies of ≈90–95% for hydrophobic T4 and 30–95% for hydrophilic HS2. The phage adsorption efficiency of Viridibacillus sp. was ≈95% for both phages and twofold higher than T4-or HS2-adsorption to their respective hosts, qualifying Viridibacillus sp. as a potential super carrier for phages. Our approach offers an effective and target-specific way to identify and isolate phage-carrying bacteria in natural and man-made environments.

Co-cultivation of Mortierellaceae with Pseudomonas helmanticensis affects both their growth and volatilome

“…Neutral or negative interactions are often unspecific and transitional. Selected soil bacteria use fungal hyphae as transport routes 4 – 6 , thus affecting fungal physiology 7 . Multiple interactions occur contemporaneously under natural conditions: a fungus can establish mutualistic interactions with one partner, but develop antagonistic ones with other soil organisms 8 .…”

Nematodes Vector Bacteriophages in Compost and Soil

“…Motile organisms, including moving patches of bacteria, growing fungi and nematodes, have all been proposed as mechanisms of phage transfer (Dennehy et al, 2006;Ping et al, 2020;You et al, 2022bYou et al, , 2022a, but these previous studies have not demonstrated their operation in spatially structured soil or compost environments. Nevertheless, this growing body of evidence supports recent interest in vectoring interactions as drivers of soil function (Muok and Briegel, 2021).…”

“…Pioneering evidence shows that microbes, including phages, may travel by attachment to motile organisms, referred to as hitchhiking. Non-host bacteria travelling along fungal hyphae can cotransport phages even across air-filled voids (You et al, 2022b(You et al, , 2022a. Nematodes, commonly referred to as roundworms, have been found to transport bacteria (Thutupalli et al, 2017) and phages in pure culture (Dennehy et al, 2006).…”

Bacteriophage Adsorption: Likelihood of Virion Encounter with Bacteria and Other Factors Affecting Rates

“…Phages also are capable of hitching rides on non-bacterial organisms, e.g., such as invertebrates [ 46 , 47 ]. Possible as well is phage movement facilitated by reversible attachment to motile but non-host bacteria [ 48 ], including with those non-host bacteria then moving along fungal mycelia [ 49 , 50 ].…”