Journal of Chemical Ecology

, Volume 40, Issue 5, pp 502–513 | Cite as

A Volatile Relationship: Profiling an Inter-Kingdom Dialogue Between two Plant Pathogens, Ralstonia Solanacearum and Aspergillus Flavus

  • Joseph E. Spraker
  • Kelsea Jewell
  • Ludmila V. Roze
  • Jacob Scherf
  • Dora Ndagano
  • Randolph Beaudry
  • John E. Linz
  • Caitilyn Allen
  • Nancy P. Keller


Microbes in the rhizosphere have a suite of extracellular compounds, both primary and secondary, that communicate with other organisms in their immediate environment. Here, we describe a two-way volatile interaction between two widespread and economically important soil-borne pathogens of peanut, Aspergillus flavus and Ralstonia solanacearum, a fungus and bacterium, respectively. In response to A. flavus volatiles, R. solanacearum reduced production of the major virulence factor extracellular polysaccharide (EPS). In parallel, A. flavus responded to R. solanacearum volatiles by reducing conidia production, both on plates and on peanut seeds and by increasing aflatoxin production on peanut. Volatile profiling of these organisms using solid-phase micro-extraction gas chromatography mass spectroscopy (SPME-GCMS) provided a first glimpse at the compounds that may drive these interactions.


Aspergillus flavus Ralstonia solanacearum Inter-kingdom Volatile organic compounds Extracellular polysaccharides Conidiation Aflatoxin 



This material is based upon work supported by the National Science Foundation under grant no. EFRI-1136903 to N.P.K. and an NSF Graduate Research Fellowship under grant no. DGE-1256259 to J.E.S. We thank Dr. Gabriel Peckham at Black Ivory Biotech for the 3. H7 cell lines, and James Starr of Texas A&M University for peanuts used in these experiments.

Supplementary material

10886_2014_432_MOESM1_ESM.docx (11 mb)
Fig S1 R. solanacearum volatiles have variable affects on fungal conidiation a) Photos of representative conidiation of different Aspergilli in axenic culture b) Photos of representative conidiation of different Aspergilli in co-culture c) Key to layout of photo for panels a and b. (DOCX 11234 kb)
10886_2014_432_MOESM2_ESM.docx (8.2 mb)
Fig S2 A. flavus produces less conidia in response to various bacteria a) Photos of representative differential conidiation of A. flavus in response to co-culture with various bacteria b) Key to layout of photo for panel a. c) Mean + SEM of conidial counts in response to co-culture with different bacteria. Asterisks indicate statistical significance according to one-way ANOVA followed by Tukey’s post-hoc test (p<0.0001, N=4). (DOCX 8381 kb)
10886_2014_432_MOESM3_ESM.docx (47 kb)
Table S1 Total compiled data from SPME-GCMS experiments. Detectable quantities for each run shown, as well as their difference and average value. (DOCX 47 kb)
10886_2014_432_MOESM4_ESM.docx (52 kb)
Table S2 Co-culture VOC analysis. Mass area data collected from two independent biological samples were averaged. Microbe specific fold changes for each volatile were calculated based on comparisons of averages with that of the co-culture reading. (DOCX 52 kb)


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Copyright information

© Springer Science+Business Media New York 2014

Authors and Affiliations

  • Joseph E. Spraker
    • 1
  • Kelsea Jewell
    • 2
  • Ludmila V. Roze
    • 3
  • Jacob Scherf
    • 2
  • Dora Ndagano
    • 4
  • Randolph Beaudry
    • 5
  • John E. Linz
    • 6
  • Caitilyn Allen
    • 1
  • Nancy P. Keller
    • 2
    • 7
  1. 1.Department of Plant PathologyUniversity of Wisconsin-MadisonMadisonUSA
  2. 2.Department of BacteriologyUniversity of Wisconsin-MadisonMadisonUSA
  3. 3.Department of Plant BiologyMichigan State UniversityEast LansingUSA
  4. 4.Walloon Centre for Industrial Biology -Technology UnitUniversity of Liège Bd. du rectoratLiègeBelgium
  5. 5.Department of HorticultureMichigan State UniversityEast LansingUSA
  6. 6.Department of Food Science and Human NutritionMichigan State UniversityEast LansingUSA
  7. 7.Department of Medical Microbiology and ImmunologyUniversity of Wisconsin-MadisonMadisonUSA

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