as an adaptation to heterogeneous environments ( young and crawford , 2004 ) , soil fungi and other mycelial microorganisms ( e.g. oomycetes ) have developed a unique ramified growth form , which is sustained by polarized internal cellular organization to support apical growth ( glass et  al . , 2004 ) . fungi represent about 75% of the subsurface microbial biomass ( 0.20.4  mg gdry soil ) with the total length of their hyphae reaching up to 1010  m per g of arable , pasture and forest topsoils respectively ( ritz and young , 2004 ) . in soil , fungi and bacteria often occupy shared microhabitats referred to as the bacterial  fungal interface ( johansson et  al . , 2004 ) . their growing mycelia continuously form new interfaces and novel ( hospitable or hostile ) microhabitats for local soil bacteria ( warmink et  al . , 2009 ) . mycelia may further modify the soil structure , enter soil pores ( wsten et  al . , 1999 ) and release nutrients and/or carbon exudates ( de boer et  al . , 2005 ) . by connecting airfilled space between waterfilled pores ( wessels , 1997 ) they also provide efficient dispersal networks [  fungal highways ( kohlmeier et  al . , 2005 ) ] for otherwise immobilized bacteria and their catabolic capabilities ( wick et  al . myceliamediated bacterial dispersal appears to depend on various factors including synergistic and antagonistic interactions , bacterial mobility ( warmink and van elsas , 2009 ) , physicochemical surface properties of bacterial and mycelial surfaces ( kohlmeier et  al . , 2005 ) or chemotactic movement along hyphae to chemoeffector hotspots ( furuno et  al . , 2010 such movement appears to facilitate the access to suitable microhabitats for growth ( nazir et  al . , 2010 ) and/or efficient contaminant biodegradation ( banitz et  al . , 2011 ) . to date , myceliamediated transport of bacteria has only been reported for axenic cultures or defined microbial communities in sterile soil and never has been applied for the extraction and isolation of contaminantdegrading bacteria from soil . in a  proof of concept study we here present a novel approach for the isolation and enrichment of naphthalene ( naph)degrading bacteria from soil by taking advantage of bacterial dispersal along the mycelia of the oomycete pythium ultimum ( maurhofer et  al . , 1992 ) . we thereby propose the use of myceliabound bacterial dispersal as a selection criterion for the targeted isolation and channelling of specialized bacteria to suitable growth environments . this study was motivated by earlier observations that mycelial growth of soil microorganisms enables the dispersal of defined bacterial populations in airfilled porous media ( leben , 1984 ; kohlmeier et  al . , 2005 ; figure  1 depicts the experimental setup and the work flow for the separation and enrichment of naphdegrading bacteria by migration along the dense mycelial network of p.  ultimum ( furuno et  al . , 2010 ) : bacterial suspensions obtained from the mineral medium agar ( mma ) positioned opposite to the soil 5 days after first contact with the hyphae ( enrichment b ) gave rise to isolated colonies on mma / naph ( enrichment d ) and r2aagar ( enrichment c ) . simultaneously , bacteria from soil overlying the p.  ultimuminoculated patch were isolated on mma / naph ( enrichment f ) . amplified 16s ribosomal dna restriction analysis ( ardra ) of the 57 isolates picked ( based on visually different morphotypes ) revealed five distinct operational taxonomic units ( otus ) . 16s rrna gene sequence analysis of several representatives of each otu identified the five otus ( sequence homology within one otu : 98100% similarity ) as arthrobacter sp . ( n  =  14 ) ( table  1 ) . except for arthrobacter sp . , all otus were found in the migrant communities . naphdegrading isolates were further tested for their ability to utilize selected polycyclic aromatic hydrocarbons ( pahs ) ( i.e. phenanthrene , fluorene , pyrene and anthracene ) . except for stenotrophomonas sp . and xanthomonas sp . , the isolates grew on most of the pahs tested ( table  1 ) . a recent study for instance revealed that mycelia allow for chemotactic movement of pahdegrading bacteria to substrate hotspots even in waterunsaturated systems ( furuno et  al . , 2010 ) . such studies support the relevance of mycelial networks for successful colonization of new microhabitats in soil ( wick et  al . , 2007 ; nazir et  al . , 2010 ) especially in vadose environments . the results of this study suggest that a majority of the cultivable naphdegrading bacterial consortium ( table  1 ) may have been capable of using the hyphal network for dispersal . were detected only in enrichment f or c , respectively ( fig .  1 ) . most isolates exhibited either swarming or swimming motility on standard agar plate assays with average colony diameters   of motile soil bacterium pseudomonas putida ppg7 ( nah7 ) but   of poorly motile mycobacterium frederiksbergense lb501 t ( table  1 ) . appears to be fully retained in the soil , whereas the likewise poorly motile rhodococcus sp . was found to move along the hydrophilic ( smits et  al . , 2003 ) hyphae of p.  ultimum . due to the suspected effect of physicochemical cell surface properties of the bacteria on myceliamediated bacterial transport ( kohlmeier et  al . , 2005 ) , the water contact angles ( w ) and potentials of the migrating bacteria were further measured as descriptors for the hydrophobicity and charge of the isolates ' cell surfaces . no significant differences , however , of w were observed with all strains being moderately hydrophobic [ w of 3070 ( table  1 ) ] according to the classification by others ( bastiaens et  al . , 2000 ) . the potentials of the isolates ranged from 3 to 46  mv and exhibited no significant difference between isolates derived from enrichments c , d ( migrant communities ) and f ( soil bacterial community ) as did the results from motility tests of the same strains the sketch of the reversed minimal medium agar ( mma ) plate depicts the microcosm employing mycelia as paths for the separation and enrichment of naphdegrading bacteria from soil : a potato dextrose agar ( pda ) piece inoculated with filamentous p.  ultimum was positioned in the lid of an upsidedown placed minimal medium agar ( mma ) plate and covered with 1.5  g of naphcontaminated urban soil ( containing the bacterial community a prior to addition to the microcosm ) allowing for >  0.5  cm headspace to the agar . the oomycete was subsequently allowed to penetrate the headspace and to serve as path for the movement of bacteria to the mma . airborne naph emanating from solid naph deposited at  >  1  cm distance to the soil served as carbon source . capital letters indicate the sample label of the trflp community analysis of bacterial 16s rrna genes ; i.e. enrichment b denominates the washoff of the migrant community from the agar surface 5 days after first contact of the hyphae with the agar , which gave rise to isolated colonies on mma / naph ( enrichment d ) and r2a agar ( enrichment c ) . simultaneously , bacteria from soil overlying the p.  ultimuminoculated patch ( community e ) were enriched on mma / naph ( enrichment f ) . please refer to supporting information for detailed description of the microcosms , the cultivation , sample handling techniques , the trflp analysis and the identification and phylogenetic characterization of the bacterial strains . origin and characterization of bacterial isolates obtained from enrichment on naph or r2a as described in fig .  1 . motility was scored as the diameter of bacterial displacement on swarm plates after incubation for 24  h at 20c . data represent the means    standard deviation from six readings of three replicate plates per treatment . growth in liquid culture on naph except for stenotrophomonas sp . and m.  frederiksbergense lb501 t with growth on r2a . growth on mma in presence of solid pah : naph  =  naphthalene ; phen  =  phenanthrene ; fluo  =  fluoranthene ; anth  =  anthracene ; pyre  =  pyrene . bacterial growth was tested on minimal medium agar ( mma ) plates with 15  mg of the corresponding solid pah spread onto the agar surface . growth and utilization of pah as carbon source was considered to take place after formation of clearly visible colonies after 17 days of incubation , otherwise not found if the strains were plated on mma in the absence of a pah source . partial sequences were deposited at genbank ( ncbi ) under the accession nos hm623661 , hm623662 , hm623664 , hm623666623673 . mycobacterium frederiksbergense lb501 t and p.  putida ppg7 ( nah7 ) are listed as reference strains of known motility and previously described ability to disperse along fungal mycelia ( kohlmeier et  al . surface motility of the strains was tested the following standard assay described previously ( baehler et  al . , 2006 ) . the zeta potential  , as an indirect measure of cell surface charge , was calculated from the electrophoretic mobility according to the method of helmholtz and smoluchowski , as presented by hiementz ( hiementz , 1986 ) . the electrophoretic mobility of bacterial suspensions in 10  mm kno3 at ph 6.2 was determined in a doppler electrophoretic light scattering analyser at 100 v as described elsewhere ( van loosdrecht et  al . , cell surface hydrophobicity was derived by the water contact angles ( w ) using an automated goniometric analysis system as described earlier ( kohlmeier et  al . development of microbial communities was followed by cultivationindependent 16s rrna genebased trflp analysis of dna isolated from soil and the total bacterial colonies on agar surface in contact with the mycelia during the experiment ( fig .  1 ) . multivariate redundancy analysis ( rda ) explained 70% of the variability of the trflp fingerprints ( fig .  2 ) and revealed considerable variations between soil prior exposure to p.  ultimum ( a ) , soil penetrated by p.  ultimum ( e ) and the bacteria mobilized by p.  ultimum ( b ) . not surprisingly , the similarities ( p  <  0.05 ) between a and b ( 22% ) , a and e ( 29% ) , as well as b and e ( 29% ) were low . higher similarities , however , were found between communities directly derived from each other by dilution and plating , namely 36% between b and c ( different csubstrate ) and 58% between b and d ( identical csubstrate ) . interestingly , a high similarity ( 63% ) between both the cultivable naphdegrading migrant ( b ) and the cultivable parent soil bacterial community profiles ( f ) was observed . this supports the hypothesis that mycelial networks confer mobility to a majority of the naphdegrading soil bacteria and likewise demonstrates that previously predicted myceliabound dispersal of axenic bacteria also holds true for native , soilbound bacteria . redundancy analysis ( rda ; shepard analysis factor : 0.091 ) depicting the qualitative similarity measure of 16s rrna gene trflp profiles of bacterial communities during separation and enrichment steps as schematized in fig .  1 . normalization of the trflp profiles and generation of a matrix with relative peak abundance for statistical analysis were performed as described in wu and colleagues ( 2009 ) using the statistical software r2.10 ( r development core team , 2009 ) . functions for identifying the  true peaks and binning the different fragment lengths are available at http://www.webpages.uidaho.edu/~joyce/lab%20page/trflpstats.html ( abdo et  al . , 2006 ) . the rda combines the spatiotemporal changes of trflp fingerprints and was conducted using r 2.10 ( r development core team , 2009 ) . the two axes represent 70% of the variance of the data . at this time , generalizations about the selectivity of the dispersal are difficult to make ; myceliamediated bacterial translocation is multifactorious and may include active flagellar or nonflagellar migration in aqueous or mucoid films surrounding the hyphae of fungi and other myceliaforming microorganisms ( wong and griffin , 1976 ; kohlmeier et  al . , 2005 ; warmink and van elsas , 2009 ) and the likely passive transport after adhesion to the apical zone of growing hyphae ( kohlmeier et  al . , 2005 ) . warmink and van elsas ( 2009 ) even found that fungusmediated dispersal may depend on bacterial community interactions as solely 4 out of 10 species migrated as single species along the mycelia of a saprotrophic fungus . bacterial migration in the hyphosphere may further be driven by other factors including random bacterial dispersal , metabolic interactions and biofilm formation on the hyphae ( freyklett et  al . , 2007 ) , chemotactic ( furuno et  al . , chemotactic swimming towards hyphae may already preselect certain bacteria by controlling the access to mycelial networks in soil as their metabolites may be available to bacterial commensals in the hyphosphere ( wick et  al . , 2010 ) . furthermore , due to the likely bioaccumulation of organic chemicals in the hyphal cell membranes , mycelia may act as an effective threedimensional biosorbent network for hydrophobic organic compounds and thus allow for easy chemotaxisdriven access of the heterogeneously distributed contaminant to degrading bacteria in the hyphosphere . this study therefore has been designed to deliver the  proof of principle that mycelia facilitate bacterial movement in nonsterilized soil and that this phenomenon may be used for the isolation of contaminantdegrading bacteria . all isolates obtained by our approach belong to genera previously known to biodegrade pahs ( e.g. efroymson and alexander , 1991 ; uz et  al . , 2000 ; polek et  al . , 2002 ; molina et  al . although no new genera were isolated by the enrichment procedures used in this study , there is much potential to tailor myceliabased enrichment setups for the isolation of bacterial strains with desired specific properties . possible variations include ( i ) the choice of the mycelial network ( e.g. phylum , physicochemical surface properties , pahdegradation capacity or other ecological traits of the hyphal microorganism ) , ( ii ) the time allowed for migration to separate bacteria of variable motility ( i.e. allowing for a chromatographic effect in the dispersal of soil bacteria ) , and ( iii ) meaningful positioning of chemoattractants or chemorepellents . beside its potential value for the isolation of novel degrader organisms , this research may lead to a better understanding of the interactions between mycelia ( of , for example , fungi ) and bacteria . it can thus result in improved remediation approaches for soils polluted with pahs or other hydrophobic organic contaminants . this study was motivated by earlier observations that mycelial growth of soil microorganisms enables the dispersal of defined bacterial populations in airfilled porous media ( leben , 1984 ; kohlmeier et  al . , 2005 ; figure  1 depicts the experimental setup and the work flow for the separation and enrichment of naphdegrading bacteria by migration along the dense mycelial network of p.  ultimum ( furuno et  al . , 2010 ) : bacterial suspensions obtained from the mineral medium agar ( mma ) positioned opposite to the soil 5 days after first contact with the hyphae ( enrichment b ) gave rise to isolated colonies on mma / naph ( enrichment d ) and r2aagar ( enrichment c ) . simultaneously , bacteria from soil overlying the p.  ultimuminoculated patch were isolated on mma / naph ( enrichment f ) . amplified 16s ribosomal dna restriction analysis ( ardra ) of the 57 isolates picked ( based on visually different morphotypes ) revealed five distinct operational taxonomic units ( otus ) . 16s rrna gene sequence analysis of several representatives of each otu identified the five otus ( sequence homology within one otu : 98100% similarity ) as arthrobacter sp . ( n  =  14 ) ( table  1 ) . except for arthrobacter sp . , all otus were found in the migrant communities . naphdegrading isolates were further tested for their ability to utilize selected polycyclic aromatic hydrocarbons ( pahs ) ( i.e. phenanthrene , fluorene , pyrene and anthracene ) . except for stenotrophomonas sp . and xanthomonas sp . , the isolates grew on most of the pahs tested ( table  1 ) . a recent study for instance revealed that mycelia allow for chemotactic movement of pahdegrading bacteria to substrate hotspots even in waterunsaturated systems ( furuno et  al . , 2010 ) . such studies support the relevance of mycelial networks for successful colonization of new microhabitats in soil ( wick et  al . , 2007 ; nazir et  al . , 2010 ) especially in vadose environments . the results of this study suggest that a majority of the cultivable naphdegrading bacterial consortium ( table  1 ) may have been capable of using the hyphal network for dispersal . were detected only in enrichment f or c , respectively ( fig .  1 ) . most isolates exhibited either swarming or swimming motility on standard agar plate assays with average colony diameters   of motile soil bacterium pseudomonas putida ppg7 ( nah7 ) but   of poorly motile mycobacterium frederiksbergense lb501 t ( table  1 ) . appears to be fully retained in the soil , whereas the likewise poorly motile rhodococcus sp . was found to move along the hydrophilic ( smits et  al . , 2003 ) hyphae of p.  ultimum . due to the suspected effect of physicochemical cell surface properties of the bacteria on myceliamediated bacterial transport ( kohlmeier et  al . , 2005 ) , the water contact angles ( w ) and potentials of the migrating bacteria were further measured as descriptors for the hydrophobicity and charge of the isolates ' cell surfaces . no significant differences , however , of w were observed with all strains being moderately hydrophobic [ w of 3070 ( table  1 ) ] according to the classification by others ( bastiaens et  al . , 2000 ) . the potentials of the isolates ranged from 3 to 46  mv and exhibited no significant difference between isolates derived from enrichments c , d ( migrant communities ) and f ( soil bacterial community ) as did the results from motility tests of the same strains the sketch of the reversed minimal medium agar ( mma ) plate depicts the microcosm employing mycelia as paths for the separation and enrichment of naphdegrading bacteria from soil : a potato dextrose agar ( pda ) piece inoculated with filamentous p.  ultimum was positioned in the lid of an upsidedown placed minimal medium agar ( mma ) plate and covered with 1.5  g of naphcontaminated urban soil ( containing the bacterial community a prior to addition to the microcosm ) allowing for >  0.5  cm headspace to the agar . the oomycete was subsequently allowed to penetrate the headspace and to serve as path for the movement of bacteria to the mma . airborne naph emanating from solid naph deposited at  >  1  cm distance to the soil served as carbon source . capital letters indicate the sample label of the trflp community analysis of bacterial 16s rrna genes ; i.e. enrichment b denominates the washoff of the migrant community from the agar surface 5 days after first contact of the hyphae with the agar , which gave rise to isolated colonies on mma / naph ( enrichment d ) and r2a agar ( enrichment c ) . simultaneously , bacteria from soil overlying the p.  ultimuminoculated patch ( community e ) were enriched on mma / naph ( enrichment f ) . please refer to supporting information for detailed description of the microcosms , the cultivation , sample handling techniques , the trflp analysis and the identification and phylogenetic characterization of the bacterial strains . origin and characterization of bacterial isolates obtained from enrichment on naph or r2a as described in fig .  1 . motility was scored as the diameter of bacterial displacement on swarm plates after incubation for 24  h at 20c . data represent the means    standard deviation from six readings of three replicate plates per treatment . growth in liquid culture on naph except for stenotrophomonas sp . and m.  frederiksbergense lb501 t with growth on r2a . growth on mma in presence of solid pah : naph  =  naphthalene ; phen  =  phenanthrene ; fluo  =  fluoranthene ; anth  =  anthracene ; pyre  =  pyrene . bacterial growth was tested on minimal medium agar ( mma ) plates with 15  mg of the corresponding solid pah spread onto the agar surface . growth and utilization of pah as carbon source was considered to take place after formation of clearly visible colonies after 17 days of incubation , otherwise not found if the strains were plated on mma in the absence of a pah source . partial sequences were deposited at genbank ( ncbi ) under the accession nos hm623661 , hm623662 , hm623664 , hm623666623673 . mycobacterium frederiksbergense lb501 t and p.  putida ppg7 ( nah7 ) are listed as reference strains of known motility and previously described ability to disperse along fungal mycelia ( kohlmeier et  al . surface motility of the strains was tested the following standard assay described previously ( baehler et  al . , 2006 ) . the zeta potential  , as an indirect measure of cell surface charge , was calculated from the electrophoretic mobility according to the method of helmholtz and smoluchowski , as presented by hiementz ( hiementz , 1986 ) . the electrophoretic mobility of bacterial suspensions in 10  mm kno3 at ph 6.2 was determined in a doppler electrophoretic light scattering analyser at 100 v as described elsewhere ( van loosdrecht et  al . , cell surface hydrophobicity was derived by the water contact angles ( w ) using an automated goniometric analysis system as described earlier ( kohlmeier et  al . development of microbial communities was followed by cultivationindependent 16s rrna genebased trflp analysis of dna isolated from soil and the total bacterial colonies on agar surface in contact with the mycelia during the experiment ( fig .  1 ) . multivariate redundancy analysis ( rda ) explained 70% of the variability of the trflp fingerprints ( fig .  2 ) and revealed considerable variations between soil prior exposure to p.  ultimum ( a ) , soil penetrated by p.  ultimum ( e ) and the bacteria mobilized by p.  ultimum ( b ) . not surprisingly , the similarities ( p  <  0.05 ) between a and b ( 22% ) , a and e ( 29% ) , as well as b and e ( 29% ) were low . higher similarities , however , were found between communities directly derived from each other by dilution and plating , namely 36% between b and c ( different csubstrate ) and 58% between b and d ( identical csubstrate ) . interestingly , a high similarity ( 63% ) between both the cultivable naphdegrading migrant ( b ) and the cultivable parent soil bacterial community profiles ( f ) was observed . this supports the hypothesis that mycelial networks confer mobility to a majority of the naphdegrading soil bacteria and likewise demonstrates that previously predicted myceliabound dispersal of axenic bacteria also holds true for native , soilbound bacteria . redundancy analysis ( rda ; shepard analysis factor : 0.091 ) depicting the qualitative similarity measure of 16s rrna gene trflp profiles of bacterial communities during separation and enrichment steps as schematized in fig .  1 . normalization of the trflp profiles and generation of a matrix with relative peak abundance for statistical analysis were performed as described in wu and colleagues ( 2009 ) using the statistical software r2.10 ( r development core team , 2009 ) . functions for identifying the  true peaks and binning the different fragment lengths are available at http://www.webpages.uidaho.edu/~joyce/lab%20page/trflpstats.html ( abdo et  al . , 2006 ) . the rda combines the spatiotemporal changes of trflp fingerprints and was conducted using r 2.10 ( r development core team , 2009 ) . the two axes represent 70% of the variance of the data . at this time , generalizations about the selectivity of the dispersal are difficult to make ; myceliamediated bacterial translocation is multifactorious and may include active flagellar or nonflagellar migration in aqueous or mucoid films surrounding the hyphae of fungi and other myceliaforming microorganisms ( wong and griffin , 1976 ; kohlmeier et  al . , 2005 ; warmink and van elsas , 2009 ) and the likely passive transport after adhesion to the apical zone of growing hyphae ( kohlmeier et  al . , 2005 ) . warmink and van elsas ( 2009 ) even found that fungusmediated dispersal may depend on bacterial community interactions as solely 4 out of 10 species migrated as single species along the mycelia of a saprotrophic fungus . bacterial migration in the hyphosphere may further be driven by other factors including random bacterial dispersal , metabolic interactions and biofilm formation on the hyphae ( freyklett et  al . , 2007 ) , chemotactic ( furuno et  al . , chemotactic swimming towards hyphae may already preselect certain bacteria by controlling the access to mycelial networks in soil as their metabolites may be available to bacterial commensals in the hyphosphere ( wick et  al . , 2010 ) . furthermore , due to the likely bioaccumulation of organic chemicals in the hyphal cell membranes , mycelia may act as an effective threedimensional biosorbent network for hydrophobic organic compounds and thus allow for easy chemotaxisdriven access of the heterogeneously distributed contaminant to degrading bacteria in the hyphosphere . this study therefore has been designed to deliver the  proof of principle that mycelia facilitate bacterial movement in nonsterilized soil and that this phenomenon may be used for the isolation of contaminantdegrading bacteria . all isolates obtained by our approach belong to genera previously known to biodegrade pahs ( e.g. efroymson and alexander , 1991 ; uz et  al . , 2000 ; although no new genera were isolated by the enrichment procedures used in this study , there is much potential to tailor myceliabased enrichment setups for the isolation of bacterial strains with desired specific properties . possible variations include ( i ) the choice of the mycelial network ( e.g. phylum , physicochemical surface properties , pahdegradation capacity or other ecological traits of the hyphal microorganism ) , ( ii ) the time allowed for migration to separate bacteria of variable motility ( i.e. allowing for a chromatographic effect in the dispersal of soil bacteria ) , and ( iii ) meaningful positioning of chemoattractants or chemorepellents . beside its potential value for the isolation of novel degrader organisms , this research may lead to a better understanding of the interactions between mycelia ( of , for example , fungi ) and bacteria . it can thus result in improved remediation approaches for soils polluted with pahs or other hydrophobic organic contaminants . additional supporting information may be found in the online version of this article : detailed information on experimental procedures on : organisms and culture conditions ; microcosm for the separation of bacteria after migration along mycelia ; isolation of naph degraders from soil ; identification and phylogenetic characterization of bacterial strains ; trflp analysis of the enriched microbial communities ; determination of physicochemical cell surface properties ; and bacterial motility assays . please note : wiley - blackwell are not responsible for the content or functionality of any supporting materials supplied by the authors . any queries ( other than missing material ) should be directed to the corresponding author for the article .
summarymycelia of fungi and soil oomycetes have recently been found to act as effective paths boosting bacterial mobility and bioaccessibility of contaminants in vadose environments . in this study , we demonstrate that mycelia can be used for targeted separation and isolation of contaminantdegrading bacteria from soil . in a  proof of concept study we developed a novel approach to isolate bacteria from contaminated soil using mycelia of the soil oomycete pythium ultimum as translocation networks for bacteria and the polycyclic aromatic hydrocarbon naphthalene ( naph ) as selective carbon source . 
 naphdegrading bacterial isolates were affiliated with the genera xanthomonas , rhodococcus and pseudomonas . except for rhodococcus 
 the naphdegrading isolates exhibited significant motility as observed in standard swarming and swimming motility assays . 
 all steps of the isolation procedures were followed by cultivationindependent terminal 16s rrna gene terminal fragment length polymorphism ( trflp ) analysis . 
 interestingly , a high similarity ( 63% ) between both the cultivable naphdegrading migrant and the cultivable parent soil bacterial community profiles was observed . 
 this suggests that mycelial networks generally confer mobility to native , contaminantdegrading soil bacteria . 
 targeted , myceliabased dispersal hence may have high potential for the isolation of bacteria with biotechnologically useful properties .