Year-end Sale % OFF 
Abstract
Burkholderia terrae BS001 has previously been found to be able to disperse along with growing fungal hyphae in soil, with the type-3 secretion system having a supportive role in this movement. In this study, we focus on the role of two motility- and adherence-associated appendages, i.e. type-4 pili (T4P) and flagella. Electron microcopy and motility testing revealed that strain BS001 produces polar flagella and can swim on semi-solid R2A agar. Flagellum- and T4P-negative mutants were then constructed to examine the ecological roles of the respective systems. Both in liquid media and on swimming agar, the mutant strains showed similar fitness to the wild-type strain in mixed culture. The flagellar mutant had completely lost its flagella, as well as its swimming capacity. It also lost its co-migration ability with two soil-exploring fungi, Lyophyllum sp. strain Karsten and Trichoderma asperellum 302, in soil microcosms. In contrast, the T4P mutant showed reduced surface twitching motility, whereas its co-migration ability in competition with the wild-type strain was slightly reduced. We conclude that the co-migration of strain BS001 with fungal hyphae through soil is dependent on the presence of functional flagella conferring swimming motility, with the T4P system having a minor effect.
Highlights
Due to a lack of connectivity of water-filled pores, or as a result of migration “barriers”, the soil environment is often not able to support the movement of bacterial cells over long distances[1]
Strain BS001 was always found to migrate in the canonical fungal growth direction and never in the opposite one, which was attributed to the older fungal mycelium becoming less active and changing the surface structure
We further explored the role of two motility- and adherence-associated cellular appendices, i.e. the flagellum and the type-4 pili (T4P), in the migration of B. terrae BS001 along with growing fungal hyphae through soil
Summary
Due to a lack of connectivity of water-filled pores, or as a result of migration “barriers”, the soil environment is often not able to support the movement of bacterial cells over long distances[1]. The type three secretion system (T3SS) was postulated to be involved in the interaction[4], recent results obtained by us show that the T3SS merely enhances the movement in soil along with fungal hyphae, but is not essential[19]. We further explored the role of two motility- and adherence-associated cellular appendices, i.e. the flagellum and the T4P, in the migration of B. terrae BS001 along with growing fungal hyphae through soil. Previous analyses of the BS001 genome demonstrated the presence of sets of both flagellar and T4P biosynthesis genes[20] These systems were not extensively studied, we here hypothesized that flagellar movement is essential for the co-migration ability of B. terrae and that type-4 pili might be involved as a ‘helper’ system at the fungal surface. We show the results of experiments aimed at elucidating these roles, and included an analysis of the effect of pH as a potential driver of motility
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
