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The biosurfactant viscosin produced by P seudomonas fluorescens SBW 25 aids spreading motility and plant growth promotion
Author(s) -
Alsohim Abdullah S.,
Taylor Tiffany B.,
Barrett Glyn A.,
Gallie Jenna,
Zhang XueXian,
AltamiranoJunqueira Astrid E.,
Johnson Louise J.,
Rainey Paul B.,
Jackson Robert W.
Publication year - 2014
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12469
Subject(s) - biology , rhizobacteria , pseudomonas fluorescens , transposon mutagenesis , motility , mutagenesis , bacteria , plant growth , mutant , flagellum , microbiology and biotechnology , botany , transposable element , biochemistry , genetics , rhizosphere , gene
Summary Food security depends on enhancing production and reducing loss to pests and pathogens. A promising alternative to agrochemicals is the use of plant growth‐promoting rhizobacteria ( PGPR ), which are commonly associated with many, if not all, plant species. However, exploiting the benefits of PGPRs requires knowledge of bacterial function and an in‐depth understanding of plant‐bacteria associations. Motility is important for colonization efficiency and microbial fitness in the plant environment, but the mechanisms employed by bacteria on and around plants are not well understood. We describe and investigate an atypical mode of motility in P seudomonas fluorescens SBW 25 that was revealed only after flagellum production was eliminated by deletion of the master regulator fleQ . Our results suggest that this ‘spidery spreading’ is a type of surface motility. Transposon mutagenesis of SBW 25Δ fleQ ( SBW 25 Q ) produced mutants, defective in viscosin production, and surface spreading was also abolished. Genetic analysis indicated growth‐dependency, production of viscosin, and several potential regulatory and secretory systems involved in the spidery spreading phenotype. Moreover, viscosin both increases efficiency of surface spreading over the plant root and protects germinating seedlings in soil infected with the plant pathogen P ythium. Thus, viscosin could be a useful target for biotechnological development of plant growth promotion agents.