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Microbial colonization and competition on the marine alga ulva australis

Microbial colonization and competition on the marine alga ulva australis
Microbial colonization and competition on the marine alga ulva australis
Pseudalteromonas tunicata and Roseobacter gallaeciensis are biofilm-forming marine bacteria that are often found in association with the surface of the green alga Ulva australis. They are thought to benefit the plant host by producing inhibitory compounds that are active against common fouling organisms. We investigated factors that influence the ability of P. tunicata and R. gallaeciensis to attach to and colonize the plant surface and also the competitive interactions that occur between these organisms and other isolates from U. australis during biofilm formation on the plant surface. A surprisingly high number of P. tunicata cells, at least 108 cells ml–1, were required for colonization and establishment of a population of cells that persists on axenic surfaces of U. australis. Factors that enhanced colonization of P. tunicata included inoculation in the dark and pregrowth of inocula in medium containing cellobiose as the sole carbon source (cellulose is a major surface polymer of U. australis). It was also found that P. tunicata requires the presence of a mixed microbial community to colonize effectively. In contrast, R. gallaeciensis effectively colonized the plant surface under all conditions tested. Studies of competitive interactions on the plant surface revealed that P. tunicata was numerically dominant compared with all other bacterial isolates tested (except R. gallaeciensis), and this dominance was linked to production of the antibacterial protein AlpP. Generally, P. tunicata was able to coexist with competing strains, and each strain existed as microcolonies in spatially segregated regions of the plant. R. gallaeciensis was numerically dominant compared with all strains tested and was able to invade and disperse preestablished biofilms. This study highlighted the fact that microbial colonization of U. australis surfaces is a dynamic process and demonstrated the differences in colonization strategies exhibited by the epiphytic bacteria P. tunicata and R. gallaeciensis
0099-2240
5547-5555
Rao, Dhana
53623cf3-0196-43cb-a592-16479aacb918
Webb, Jeremy S.
ec0a5c4e-86cc-4ae9-b390-7298f5d65f8d
Kjelleberg, Staffan
043b66b5-130c-42f2-99b3-ec3eecf3248e
Rao, Dhana
53623cf3-0196-43cb-a592-16479aacb918
Webb, Jeremy S.
ec0a5c4e-86cc-4ae9-b390-7298f5d65f8d
Kjelleberg, Staffan
043b66b5-130c-42f2-99b3-ec3eecf3248e

Rao, Dhana, Webb, Jeremy S. and Kjelleberg, Staffan (2006) Microbial colonization and competition on the marine alga ulva australis. Applied and Environmental Microbiology, 72 (8), 5547-5555. (doi:10.1128/AEM.00449-06). (PMID:16885308)

Record type: Article

Abstract

Pseudalteromonas tunicata and Roseobacter gallaeciensis are biofilm-forming marine bacteria that are often found in association with the surface of the green alga Ulva australis. They are thought to benefit the plant host by producing inhibitory compounds that are active against common fouling organisms. We investigated factors that influence the ability of P. tunicata and R. gallaeciensis to attach to and colonize the plant surface and also the competitive interactions that occur between these organisms and other isolates from U. australis during biofilm formation on the plant surface. A surprisingly high number of P. tunicata cells, at least 108 cells ml–1, were required for colonization and establishment of a population of cells that persists on axenic surfaces of U. australis. Factors that enhanced colonization of P. tunicata included inoculation in the dark and pregrowth of inocula in medium containing cellobiose as the sole carbon source (cellulose is a major surface polymer of U. australis). It was also found that P. tunicata requires the presence of a mixed microbial community to colonize effectively. In contrast, R. gallaeciensis effectively colonized the plant surface under all conditions tested. Studies of competitive interactions on the plant surface revealed that P. tunicata was numerically dominant compared with all other bacterial isolates tested (except R. gallaeciensis), and this dominance was linked to production of the antibacterial protein AlpP. Generally, P. tunicata was able to coexist with competing strains, and each strain existed as microcolonies in spatially segregated regions of the plant. R. gallaeciensis was numerically dominant compared with all strains tested and was able to invade and disperse preestablished biofilms. This study highlighted the fact that microbial colonization of U. australis surfaces is a dynamic process and demonstrated the differences in colonization strategies exhibited by the epiphytic bacteria P. tunicata and R. gallaeciensis

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Published date: August 2006

Identifiers

Local EPrints ID: 186815
URI: http://eprints.soton.ac.uk/id/eprint/186815
ISSN: 0099-2240
PURE UUID: 7fed96ba-e7dc-44ae-84ec-91fa7ec60302
ORCID for Jeremy S. Webb: ORCID iD orcid.org/0000-0003-2068-8589

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Date deposited: 18 May 2011 14:04
Last modified: 15 Mar 2024 03:26

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Contributors

Author: Dhana Rao
Author: Jeremy S. Webb ORCID iD
Author: Staffan Kjelleberg

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