Effects of Jasmonic Acid, Ethylene, and Salicylic Acid Signaling on the Rhizosphere Bacterial Community of Arabidopsis thaliana

Plant-Microbe Interactions, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Molecular Plant-Microbe Interactions (Impact Factor: 4.46). 04/2011; 24(4):395-407. DOI: 10.1094/MPMI-05-10-0115
Source: PubMed

ABSTRACT Systemically induced resistance is a promising strategy to control plant diseases, as it affects numerous pathogens. However, since induced resistance reduces one or both growth and activity of plant pathogens, the indigenous microflora may also be affected by an enhanced defensive state of the plant. The aim of this study was to elucidate how much the bacterial rhizosphere microflora of Arabidopsis is affected by induced systemic resistance (ISR) or systemic acquired resistance (SAR). Therefore, the bacterial microflora of wild-type plants and plants affected in their defense signaling was compared. Additionally, ISR was induced by application of methyl jasmonate and SAR by treatment with salicylic acid or benzothiadiazole. As a comparative model, we also used wild type and ethylene-insensitive tobacco. Some of the Arabidopsis genotypes affected in defense signaling showed altered numbers of culturable bacteria in their rhizospheres; however, effects were dependent on soil type. Effects of plant genotype on rhizosphere bacterial community structure could not be related to plant defense because chemical activation of ISR or SAR had no significant effects on density and structure of the rhizosphere bacterial community. These findings support the notion that control of plant diseases by elicitation of systemic resistance will not significantly affect the resident soil bacterial microflora.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Induced systemic resistance (ISR) has been described for several strains of fluorescent pseudomonads in a variety of crop plants and is effective against a wide range of pathogens. Using the model plant Arabidopsis thaliana, progress has been made in understanding signal transduction pathways involved in induced resistance. Perception of ethylene and jasmonic acid is important for ISR. The traits of Pseudomonas spp. that can trigger ISR appear to be diverse, and include iron regulated metabolites, antibiotics, and lipopolysaccharides. Since pathogen growth is restricted on plants that are in the state of ISR, we hypothesized that the indigenous microflora could also be affected by ISR. Using cultivation dependent techniques, effects of plant defense signaling on the total bacterial and the Pseudomonas spp. microflora of Arabidopsis were studied and related to susceptibility of Arabidopsis genotypes to bacterial speck caused by Pseudomonas syringae pv. tomato.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Mutualistic microbes present in plant-associate microbial communities provide a variety of benefits for their host, including reciprocal exchange of nutrients and/or protection from biotic and abiotic environmental stresses. Plant microbiomes have remarkably robust composition in comparison to the complex and dynamic microbial environments from which they form, suggesting finely tuned discrimination by the plant host. Here the intersection between the plant immune system and microbiomes will be explored, both as a possible means of shaping community membership and as a consequence elicited by certain colonizing microbes. Notably, the advent of massive parallel sequencing technologies allows the investigation of these beneficial microbial functions within whole community settings, so we can now ask how engagement of the immune response influences subsequent microbial interactions. Thus, we are currently poised for future work defining how the plant immune system impacts microbiomes and consequently host health, allowing us to better understand the potential of plant productivity optimization within complex microbial surroundings.
    Frontiers in Plant Science 06/2014; 5:287. DOI:10.3389/fpls.2014.00287 · 3.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The identity of plant host genetic factors controlling the composition of the plant microbiota and the extent to which plant genes affect associated microbial populations is currently unknown. Here, we use a candidate gene approach to investigate host effects on the phyllosphere community composition and abundance. To reduce the environmental factors that might mask genetic factors, the model plant Arabidopsis thaliana was used in a gnotobiotic system and inoculated with a reduced complexity synthetic bacterial community composed of seven strains representing the most abundant phyla in the phyllosphere. From a panel of 55 plant mutants with alterations in the surface structure, cell wall, defense signaling, secondary metabolism, and pathogen recognition, a small number of single host mutations displayed an altered microbiota composition and/or abundance. Host alleles that resulted in the strongest perturbation of the microbiota relative to the wild-type were lacs2 and pec1. These mutants affect cuticle formation and led to changes in community composition and an increased bacterial abundance relative to the wild-type plants, suggesting that different bacteria can benefit from a modified cuticle to different extents. Moreover, we identified ein2, which is involved in ethylene signaling, as a host factor modulating the community's composition. Finally, we found that different Arabidopsis accessions exhibited different communities, indicating that plant host genetic factors shape the associated microbiota, thus harboring significant potential for the identification of novel plant factors affecting the microbiota of the communities.
    PLoS Genetics 04/2014; 10(4):e1004283. DOI:10.1371/journal.pgen.1004283 · 8.17 Impact Factor

Full-text (2 Sources)

Available from
Jun 3, 2014