Abstract
Plant growth promoting pseudomonads play an important role in disease suppression and there is considerable interest in development of bio-marker genes that can be used to monitor these bacteria in agricultural soils. Here, we report the application ofa PCR primer sets targeting genes encoding the main antibiotic groups. Distribution of the genes was variably distributed across type strains of 28 species with no phylogenetic groupingfor the detected antibioticsgenes, phlD for 2,4-diacetylphloroglucinol (2,4-DAPG) and phzCD for phenazine-1-carboxylic acid or hcnBC for hydrogen cyanide production. Analysis of field soils showed that primer sets for phlD and phzCD detected these genes in a fallowed neutral pH soil following wheat production, but that the copy numbers were below the detection limits in bulk soils having an acidic pH. In contrast, PCR products for the phzCD, pltc and hcnBc genes were detectable in mature root zones following plantingwith wheat. The ability to rapidly characterize populations of antibiotics producers using specific primer sets will improve our ability to assess the impacts of management practices on the functional traits of Pseudomonas spp. populations in agricultural soils.
Highlights
Plant growth promoting rhizosphere bacteria improve plant growth through the production of hormones and by suppression of root disease through the production of antibiotics and siderophores
PCR primer sets for conserved sequences of genes involved in expression and regulation of six antibiotics were targeted against 28 type strains of Pseudomonas spp
The objective of this study was to evaluate a selected set of gene targets for detection of Pseudomonas sp. and functional genes for antibiotic production, regulation of cyanide and antibiotic production, and plant growth hormone production across different soil types representing a range of important soils used for wheat production in Australia
Summary
Plant growth promoting rhizosphere bacteria improve plant growth through the production of hormones and by suppression of root disease through the production of antibiotics and siderophores. Genes encoding the antibiotics pyoluteorin (pltC) [1], pyrrolnitrin (prnD) [1], phenazine-1-carboxylic acid (phzCD) [3], and 2,4-diacetylphloroglucinol (2,4-DAPG, phlD) [3] are a major focus of research in biological control of disease by pseudomonads. Other genes that are relevant to biocontrol include the gacA and hcnBC genes encoding hydrogen cyanide production. The gacA gene (global activator of cyanide production) is a response regulator that interacts with quorum regulated genes to control expression of small RNAs and antibiotics in various strains of PGPR pseudomonads [16]. In the PGPR bacterium P. chlororaphis, gacA functions as a negative regulator of indole-3-acetic acid hormone production. The genes encoding aminocyclopropane carboxylic acid deaminase (acc) are still other potential targets, functioning for the destruction of ethylene [17,18]
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.
