ORI GI NALARTI CLE Open AccessCommon gas phase molecules from fungi affectseed germination and plant health in ArabidopsisthalianaRichard Hung1*, Samantha Lee1, Cesar Rodriguez-Saona2and Joan W Bennett1AbstractFungal volatile organic compounds (VOCs) play important ecophysiological roles in mediating inter-kingdom signalingwith arthropods but less is known about their interactions with plants. In this study, Arabidopsis thaliana was usedas a model in order to test the physiological effects of 23 common vapor-phase fungal VOCs that included alcohols,aldehydes, ketones, and other chemical classes. After exposure to a shared atmosphere with the 23 individual VOCs for72 hrs, seeds were assayed for rate of germination and seedling formation; vegetative plants were assayed for freshweight and chlorophyll concentration. All but five of the VOCs tested (1-decene, 2-n-heptylfuran, nonanal, geosminand -limonene) had a significant effect in inhibiting either germination, seedling formation or both. Seedling formationwas entirely inhibited by exposure to 1-octen-3-one, 2-ethylhexanal, 3-methylbutanal, and butanal. As assayed by acombination of fresh weight and chlorophyll concentration, 2-ethylhexanal had a negative impact on two-week-oldvegetative plants. Three other compounds (1-octen-3-ol, 2-ethylhexanal, and 2-heptylfuran) decreased fresh weightalone. Most of the VOCs tested did not change the fresh weight or chlorophyll concentration of vegetative plants. Insummary, when tested as single compounds, fungal VOCs affected A. thaliana in positive, negative or neutral ways.Keywords: Volatile organic compound; Arabidopsis thaliana; Fungi; Seed germination; Chlorophyll concentration;Gas chromatography; Mass spectroscopyIntroductionVolatilesorganiccompounds(VOCs)arelowmolecularmass compounds withhighvapor pressureandlowtomedium water solubility that exist in the gaseous state atroom temperature (Herrmann 2010). Approximately 250VOCs have been identified fromfungi (Chiron andMichelot 2005) asthe products ofboth primary andsec-ondary metabolism(Turner and Aldridge 1983; Korpiet al. 2009). Thesegas phasemolecules areemittedincomplex mixtures that vary quantitatively and qualitativelydepending not only on the age and genetic profiles of theproducingspeciesbutalsoonextrinsicvariablessuchassubstrate, temperature, moisturelevel andpH(Sunessonet al. 1995; Claeson et al. 2002; Matysik et al. 2008). Fun-gal volatileshavedistinctiveodorantpropertiesandtheyhave been studied extensively for their positive andnegativesensoryproperties. They impart unique aromasand flavors to mold-ripened cheeses, Japanese koji andother mold-fermented food products (Steinkraus 1983;Kinderlerer1989), andareresponsibleforthebouquetofgourmet mushrooms such as boletes, chanterelles and truf-fles (Cho et al. 2008; Fraatz and Zorn 2010). On the negativeside, when foodsarecontaminatedbymolds, theyproduceoff flavors. VOCs have been used as an indirect indicator offungal spoilage in agricultural products (Borjesson et al.1992; Jelen and Wasowicz 1998; Schnrer et al. 1999) and ofmold contamination in water-damaged buildings (Kuskeet al. 2005; Sahlberg et al. 2013). Finally, because VOCs candiffusethroughtheatmosphereandthesoil, theyarewelladapted for signaling between species that share a commonecological niche. Both bacterial and fungal VOCs play com-petitiverolesinchemicalinteractionsbetweenmicroorgan-isms(BeattieandTorrey1986; Morathetal. 2012). Manyplant andmicrobial volatilemolecules functionas semio-chemicals, otherwise known as infochemicals, and there isalargeliteratureontheabilityoffungal VOCstomediate* Correspondence: Richard.Hung@rutgers.edu1Department of Plant Biology and Pathology, Rutgers, The State University ofNew Jersey, 59 Dudley Rd., New Brunswick, NJ 08901, USAFull list of author information is available at the end of the article 2014 Hung et al.; licensee Springer. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproductionin any medium, provided the original work is properly cited.Hung et al. AMB Express 2014, 4:53http://www.amb-express.com/content/4/1/53arthropodbehavior, wheretheyhavepropertiesassyno-mones, allomones, andkairomones (Rohlfs et al. 2005;Mburuet al. 2011; Daviset al. 2013). Thefungal VOCcommonly calledmushroom alcohol (1-octen-3-ol) is re-sponsible for much of the musty odor associated with moldcontamination and is an important insect semiochemical. Itattracts manyinsect species, includingthemalariamos-quito (Takken and Knols 1999; Thakeow et al. 2008).Incontrast, the interactions betweenfungal VOCsandplantshavenotreceivedmuchscientificattention(Bitasetal. 2013). Basedontheobservationthatthereisverylittlevegetationinareasknowntohavetruffles(subterranean gourmet fungi), it has been hypothesizedthatthesefungi mayhavetheabilitytosuppressplantgrowththroughtheir volatiles (Splivalloet al. 2007).Kishimotoet al. (2007) haveshownthat 1-octen-3-olenhances resistance of mature plants of ArabidopsisthalianatoBotrytiscinereaandactivatessomeof thesame defense genes turned on by ethylene and jasmonicacidsignaling, important plant hormones involvedinplant defense.We hypothesizedthat we coulddistinguishbetweenbioactiveandinactivefungal vapors byusingchemicalstandards of individual VOCs and then exposing plants tocontrolled concentrations in a model habitat. We selectedA. thalianaasourtestspeciesduetothemanybenefitsassociated with the use of a well recognized model systemincludingbut not limitedto: small size, short lifecycle,genetic tractability, and comprehensively researched back-ground. Preliminary studieshave also shown that tomatoplantsexposedtoVOCsareaffectedinasimilarfashionto A. thaliana exposed to the same VOCs indicating thatA. thaliana is a good model organism for study. Similarly,theeffects of fungal VOCs onplant development havebeen demonstrated in several plants in Brassicaceae familyincluding radish, cabbage, rape, and broccoli (Ogura et al.2000). The aim of our study was to evaluate the effect ofindividual fungal VOCs onseedgermination, vegetativeplant growthandchlorophyll concentrationinacon-trolledenvironment. Inthisreport, ourspecificobjec-tiveshavebeentocreatestandardizedmodel exposurehabitats inorder tocomparethepossible stimulatoryand inhibitory effects of fungal VOCs fromdifferentchemicalclasses(e.g., alcohols, aldehydes, ketones, andso forth) and to conduct exposure studies using A. thalianaseeds and two-week-old vegetative plants.Materials and methodsPlant material and seed preparationAll volatileexposuretests weredonewithArabidopsisthaliana ecotype Columbia 7. Surface-sterilization of seedsand seedling formationstudies were conductedas de-scribedpreviouslywithslight modifications(Hunget al.2013). SurfacesterilizedseedsweresownonMurashigeandSkoog(MS)mediawithvitamins, 3%sucrose, and0.3% Gellan Gum Powder (G 434 PhytoTechnology La-boratories, Shawnee Mission, KS). In germination-seedlingformationstudies, seedsweresownonPetridishes(20seedsperplate)with20ml MSmediaandplacedat4Cinthedarkforthreedaystostratifytheseeds. Seeds used to grow plants for exposure assays oftwoweek old plants were sown individually in testtubes with 10 ml of MS, covered with plant tissuecul-turecapsandthenstratifiedasdescribedabove. Afterthreedays, thestratifiedseedsintheirindividual testtubeswereplacedinagrowthchamberat 21C 2Cwith a 16 hour photoperiod for two weeks prior to ex-posure to VOCs.Chemicals and exposure conditionsAuthentic standardsof these highpurity chemicals werepurchasedinliquidform fromSigma-Aldrich(St. Louis,Missouri). The criteriafor theselectionof thesecom-poundswere: 1) thevolatilesshouldrepresent differentchemical classes, 2) they had been isolated fromarange of fungal species including both mushrooms andmolds, and3) that theyincludedseveral VOCscom-monly found in soils.The germination and vegetative exposure to VOCswere determined using the methods described previously(Hung et al. 2014; Lee et al. 2014). Seeds (in Petri plates)or two-week-oldplants (inindividual test tubes) wereexposedinoneliterculturevessels(seeAdditional file1). Alltestsweredoneatalowconcentrationsimilartothe concentration of VOCs analyzed previously: one partpermillion(1ppm= 1l/l). Thedesiredconcentrationof1ppminthetestcontainerwasobtainedbydeposit-ing a dropof the chemical standard(VOC) inliquidform onto the inside of the glass vessel. The compounds,due totheir chemical properties will quickly volatilizeintothegasphaseinthetestconditions. Beforesealingthe lids, a 10 10 cm piece of Dura Seal Cling Sealing Film(Diversified Biotech) was placed over the top of each culturevessel so as to prevent VOC leakage through the polypropyl-eneclosure. TheculturevesselscontainingeitherseedsinPetri platesor two-week-oldplantsin test tubes were ar-ranged randomly in the growth chamber and then placedon a one inch throw rotator at 40 rpm in order to volatilizeandevenlydistributethecompounds. Thecontrol plantswere placed in identical conditions without any VOCs.Scoring germination stagesThe seeds were exposed to the individual VOCs for72hoursandthenexaminedunderabinocularmicro-scopewheretheywerescoredintothreecategories: nogermination, germination(emergenceoftheradical[em-bryonicroot]), andseedlingformation(presenceof theradicle, the hypocotyls and the cotyledons) (see AdditionalHung et al. AMB Express 2014, 4:53 Page 2 of 7http://www.amb-express.com/content/4/1/53file2). Seedsscoredasnogerminationincludedseedswith a ruptured testa (seed coat) but without the presenceof the radicle.Plant mass and chlorophyll concentrationAfter exposure to the vapors of the individual VOCs,plantswereremovedfromthetestconditions, theshootand leaves were cut away from the roots, and fresh weightof theshoots andleaves was obtained. Thechlorophyllwas extractedusingthemethodof Jingetal. (2002)withsomemodifications. Theplantsweresoakedovernightin80%acetoneat 4Cindarkness prior toobtainingphotometric readings at 663 and 645 nm with a spectro-photometer (DU800, Beckman Coulter, Brea, CA). Totalchlorophyll = 20.2 (A645) + 8.02 (A663)(V/1,000 * w) whereV= total volume of the sample, w= weight of the sample,A663= absorbance at 663 nm, A645= absorbance at645nm(Palta1990). Eachsolventextractcontainedoneplant per treatment.Statistical analysisThe data were analyzed and plotted using Excel software(Microsoft, Redmond, WA) andSigmaPlot (SPSS Sci-enceInc., IL). Totest thesignificanceof theexposurestudies, one-way analysis ofvariance (ANOVA) and Stu-dentst-testswereperformedwiththeaggregateddata.The Students t-tests determine if there are significant dif-ferencesbetweentwosetsofdata: thecontrol andVOCexposedplants. Forgerminationexposures, tworeplicateplateswith20seedsperplateweretestedforeachcom-pound, withtwoindependentexperiments, foratotal of80seeds. Forvegetativeplantexposure, fourplantswereplaced in the exposure vessel and three jars were used foreachexperiment. Therewerethreeindependent experi-ments for each compound, for a total of 36 plants.ResultsSeedling formation testsThepercentageofseedsgerminatingandprogressingtoseedlingformationafterexposuretothe23fungal vola-tilesisshowninFigure1andsummarizedinFigure2.In our experiments, more than 75% of control seeds pro-gressed to the seedling stage after 72 hrs. Similar rates ofseedling formation were observed for seeds exposed to 1-decene, 2-n-heptylfuran, nonanal, geosmin and -limonene.Incontrast, noneoftheseedsexposedto2-ethylhexanal1-octen-3-one, 3-methylbutanal, orbutanal formedseed-lings. Of these four inhibitory volatiles, radical protrusion(i.e. germination) was observed in only 19% of 1-octen-3-one exposed seeds, while 83% of seeds exposed to butanalexhibitedformationofaradical. Seedsexposedtotheother 14 volatile compounds tested had intermediate levelsof germination efficiency and seedling formation (Figure 2).Of thefivealdehydeswetested, three(2-ethylhexanal,3-methylbutanal, orbutanal) inhibitedseedlingforma-tion by 100%and one (3-methylproponal) inhibitedseedlingformation by 70%. Nevertheless, no matter theextent of inhibition in the presence of the 23 VOCs tested,when removed from exposure to the VOCs after 72 hr, allseeds resumed germination and formed seedlings.Vegetative plants testsThefreshweightandchlorophyll concentrationofcon-trolandexposedplantsaregiveninFigure3. Thefreshweight of control plants was 22.4 mg (6.7 SE). Asignificantdecreaseinfreshweightwasobservedafter72hrexposureto1-octen-3-ol, 2-ethylhexanal, and2-heptylfuran, where the mean fresh weight was respectively6.7 mg (2.7 SE), 11.2 mg (4.9 SE), and 6.3 mg (5.4 SE)less than controls. The other compounds tested (()2-methyl-1-butanol, geosmin, 2-methylpropan-1-ol, 1-octen-3-ol, octan-1-ol, octan-3-ol, dec-1-ene, oct-1-ene, butanal,2-ethylhexanal, 2-methylpropanal, 3-methylbutanal, nona-nal, heptan-2-one, octan-2-one, oct-1-en-3-one, pentan-2-one, isothiocyanatocyclohexane, octanoic acid, +limonene,limonene, and2-heptylfuran) didnot causesignificantdifferences infreshweight of exposedvegetativeplants(Figure 3).In Figure 3, we have expressed thechlorophyll concen-tration data as mg/gmof fresh weight of shoots andleaves. Fivecompounds (2-methyl-1-butanol, 1-octen-3-ol, dec-1-ene, heptan-2-one, and isothiocyanatocyclo-hexane) yielded statistically significant increases inchlorophyll concentration showing, respectively, 0.02 mg/g,0.2mg/g, 0.18mg/g, 0.02mg/g, and0.4mg/ggreateramountsthancontrols. Threecompounds, geosmin, 2-ethylhexanal, and 1-octen-3-one caused a statisticallysignificant decrease in chlorophyll concentration of, respect-ively, 0.15 mg/g, 0.35 mg/g, and 0.42 mg/g less than controls.Whilegeosmindidnotadverselyaffectfreshweight, itdidcauseasignificantdecreaseinchlorophyllconcentrationasindicatedabove. Thecompound2-ethyl-hexanal decreasedbothfreshweight andchlorophyll concentration. Thenonracemicformof2-methyl-1-butanol showedasmallbut significantly different increase in both parameters.Inconclusion, all but fiveof theVOCs testedhadasignificanteffectininhibitingeithergermination, seedlingformation or both. Three of the compounds (2-ethyl-hexanal, 1-octen-3-one, and 3-methylbutanal) showed morethan50%inhibitionof seedgermination, while12of thecompounds (2-methylpropan-1-ol, 2-methylpropanal,heptan-2-one, octan-2-one, isothiocyanatocyclohexane,pentan-2-one, octan-3-ol, 1-octen-3-ol, 2-ethylhexanal,1-octen-3-one, 3-methylbutanal, andbutanal) wereas-sociatedwithmorethana50%retardationinseedlingformation. Butanal was unusual inthat 83%of seedsgerminated (i.e. formed a radicle) but none of thesegerminatedseedsprogressedtoseedlingformation. InHung et al. AMB Express 2014, 4:53 Page 3 of 7http://www.amb-express.com/content/4/1/53general, the most bioactive of the VOCs we tested werealdehydes and ketones. The single, most inhibitory VOCagainstgerminationandseedlingformationwasoct-1-en-3-one, an eight carbon ketone that has been isolatedfrombothmoldsandmushrooms(JelenandWasowicz1998). Nevertheless, inall cases, VOCexposedseedswereabletoresumegerminationandprogresstoseed-lingstagewhenremovedfromthesharedatmospherewiththeVOC. Weconcludethatthefungal VOCswetestedhaveaphytostatic(inhibitory), not aphytocidal(lethal) effect on seeds.DiscussionIn order to study the influence of individual fungalVOCsonplant health, weusedA. thalianaasourtestorganism and developed standardized protocols for expos-ingseedsandyoungvegetativeplants. Weinvestigatedarepresentative sample of commonfungal VOCs encom-passing seven alcohols, two alkenes, five aldehydes,fourketones, andasinglerepresentativeisothiocyan-ate, carboxylicacid, andfuran. Inaddition, wetestedbothisomersof theterpene1-methyl-4-(1-methyetenyl)-cyclohexene, commonlyknownaslimonene. Weuseda0102030405060708090100Percent of seedsSeedling FormationSeedlingGerminated onlyNo germinationFigure 1 Percentage of seeds that have reached each stage after 72 hrs of exposure to 23 fungal VOCs. Standard error indicated inerror bars.>75%>50%>6%= 2-5%0%Controldec-1-ene2-heptylfurannonanalgeosmin(-)limonene(-)2-methyl-1-butanol(+)limoneneoctanoic acid()2-methyl-1-butanoloct-1-eneoctan-1-ol2-methylpropan-1-ol2-methylpropanalheptan-2-oneoctan-2-oneisothiocyanatocyclohexanepentan-2-oneoctan-3-oloct-1-en-3-ol2-ethylhexanaloct-1-en-3-one3-methylbutanalbutanalFigure 2 A summary of the categories of percent seedling formation of A. thaliana seeds after 72 hrs of exposure to chemical standards of23 different volatile organic compounds.Hung et al. AMB Express 2014, 4:53 Page 4 of 7http://www.amb-express.com/content/4/1/5372hour exposure period, andexposedeither seeds oryoung vegetative plants to 1 ppm of chemical standards ofthe 23 fungal VOCs in a contained chamber.Seedgerminationassays withlettuce, cucumber andothereconomicallyimportant specieshavebeenwidelyemployedaslow-cost, ethicallyacceptabletoxicityteststoscreenfor dangerous levels of industrial contamin-ationinwaterandsoils(BanksandSchultz2005; Wanget al. 2001). Almost all of theseassaystudies havein-volvedaqueousphasecompounds, althoughtherehavebeenafewscatteredreportsdescribinginhibitoryeffectofplantvolatilesonthegerminationofseedsfromcropand weed species (Holm1972; Bradowand Connick1990). Thephysiological basisforthisinhibitoryactionhas not been elucidated. A. thaliana, though not agricul-turallyimportant, offers anumber of experimental ad-vantages for studying basic aspects of plant biology,includingseedgermination, becauseofitsmanygeneticresources(Koornneef et al. 2002). Our development ofan A. thaliana exposure system for studying VOC effectsundercontrolledconditionsoffersthepromiseof beingable to use this species to dissect the germination inhib-ition response at the molecular level.Incontrasttoseedgerminationstudies, whichall re-port inhibitionof germinationby VOCs (Holm1972;Frenchet al. 1975; BradowandConnick1990). Todate,publishedstudies of theeffects of VOCs onvegetativeplants report VOCassociated growth stimulation bymixturesofVOCsemittedbygrowingbacteriaorfungi(Ryuet al. 2003; Minerdi etal. 2011; Hunget al. 2013;Paul andPark2013). Manysoil dwellingmicrobesemitVOCs that mediate various chemicalconversations be-tweenthe rhizosphere andplants (Wenke et al. 2010,2012). For example, plant growthpromotingrhizobac-teria (PGPR) producemixtures of VOCs that enhancegrowthinawidevarietyof species (Faraget al. 2006;Vespermann et al. 2007; Lugtenberg and Kamilova2009). Insomecases, microbial VOCsinducesystemicresistance (Van Loon et al. 1998; Ryu et al. 2003) or inhibitthe growth of plant pathogens (Minerdi et al. 2009, 2011).Volatiles of Cladosporium cladosporioides enhance growthof tobacco plants (Paul and Park 2013) and our laboratoryhasshownthat vegetativeplantsofA. thalianaseedlingsgrowninasharedatmospherewithvolatilesemittedbyliving cultures of the biocontrol fungus Trichodermaviride, displayedincreasedsizeandvigor (Hunget al.ab*****0510152025303540C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23Fresh Weight (mg)Volatile Organic CompoundsFresh Weight* ** ** ***00.511.522.53C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23Chlorophyll Concentration (mg/g)Volatile Organic CompoundsChlorophyll ConcentrationLegendC Control 6 octan-1-ol 12 2-methylpropanal 18 pentan-2-one1 ()2-methyl-1-butanol 7 octan-3-ol 13 3-methylbutanal 19 isothiocyanatocyclohexane2 -2-methyl-1-butanol 8 dec-1-ene 14 nonanal 20 octanoic acid3 geosmin 9 oct-1-ene 15 heptan-2-one 21 +limonene4 2-methylpropan-1-ol 10 butanal 16 octan-2-one 22 -limonene5 1-octen-3-ol 11 2-ethylhexanal 17 oct-1-en-3-one 23 2-heptylfuranFigure 3 Fresh weight and chlorophyll concentration of two week old plants of A. thaliana exposed for 72 hrs to chemical standardsof 23 different fungal volatile organic compounds. a. Fresh weight in mg. b. Chlorophyll concentration in mg/g. Significant values comparedto control are marked with an asterisk p < 0.04. Standard error indicated in error bars.Hung et al. AMB Express 2014, 4:53 Page 5 of 7http://www.amb-express.com/content/4/1/532013). Fungal VOCs may contribute to the ability of certainspecies to outcompete neighboring plants. For example, theVOCs produced by Muscodoryucantanensis were toxic totheroots, andinhibitedseedgermination, ofamaranth,tomato and barnyard grass (Macias-Rubalcava et al.2010). In all of these cases, the growth-enhancing effectsweremediatedbymixturesof naturallyemittedVOCsthat change with both growth phase and extrinsic envir-onmental parameters.In our studies, we used a controlled system and exposedplantstolowconcentrationsof individual VOCs. Inthiscontrolledhabitat, theVOCstestedeitherhadneutral ornegative effects on vegetative plant growth, suggesting thatthe known growth enhancing effects of bacterial and fungalVOCs maybe by synergistic mixtures working in concert. Aparallel example is provided by the antibiotic effects of vo-latiles produced by Muscodor albus. This species producesamixtureof VOCsthat inhibit andkill awiderangeofplant pathogenicfungi andbacteria(Strobel et al. 2001).Nevertheless, when Muscodor VOCs were tested individu-ally, the inhibitory effects were not observed, suggestingthat theantifungal activityrequiredasuiteof VOCsworking in concert (Strobel et al. 2001).ItshouldberecognizedthatstudiesontranskingdomsignallingmediatedbyfungalVOCsaretechnicallydif-ficult to conduct. Biogenic VOCs exhibit enormous het-erogeneity chemically, spatially, and temporally; arefoundinlowconcentrations; andbydefinitionhavein-nateevaporativepropertiesthatmakeitdifficulttoin-vestigate their impact on plant growth and developmentin natural settings. Our exploratory research shows thatby using controlled concentrations of pure syntheticcompoundsinmodel habitats, individual VOCscanbestudied one by one, thereby isolating their distinctgrowth-promoting, growth-inhibitingandother physio-logical effects. The genetic and genomic resources avail-ableforA. thalianamakethisorganismwellsuitedforfuture research on the mechanistic basis of VOC medi-ated interactions and for analysis of the consequent bio-logical responses. Insummary, thestudyof gasphasefungal metabolites offers many interesting prospects forenlarging our understanding of the way inwhichfungiinteractwithplantsinnatureandmayhavepotential forcommercial application of VOCs in greenhouse agriculture.Additional filesAdditional file 1: Diagrams of exposure chambers for a. seeds inPetri dishes and b. plants in test tubes.Additional file 2: Representative images of stages of seedlingformation A) No germination B) Germination, radical protrusion C)Seedling formation.Competing interestsThe authors declare that they have no competing interests.Authors contributionsRH designed the volatile exposure studies. In addition, he participated in thevolatile exposure experiments and the drafting of the paper. SL participatedin the exposure experiments and the drafting of the paper. CR-S collectedand analyzed the volatile organic compounds. JWB conceived the study andparticipated in the drafting of the paper. All authors read and approved thefinal manuscript.AcknowledgementsWe thank Barbra Zilinskas, Chee-kok Chin, and Prakash Masurekar for theirguidance and perspective. We also thank Elvira de Lange for helpfulcomments on an earlier draft of the manuscript. This research was supportedby funds from Rutgers, The State University of New Jersey and National ScienceFoundation Graduate Research Fellowship under Grant No. 0937373 to SL.Author details1Department of Plant Biology and Pathology, Rutgers, The State University ofNew Jersey, 59 Dudley Rd., New Brunswick, NJ 08901, USA.2Department ofEntomology, Rutgers, The State University of New Jersey, 96 Lipman Drive,New Brunswick, NJ 08901, USA.Received: 21 May 2014 Accepted: 5 June 2014ReferencesBanks MK, Schultz KE (2005) Comparison of plants for germination toxicity testsin petroleum-contaminated soils. Water Air Soil Pollut 167:211219Beattie SE, Torrey GS (1986) Toxicity of methanethiol produced by Brevibacteriumlinens toward Penicillium expansum. J Agr Food Sci 34:102104Bitas V, Kim H-S, Bennett J, Kang S (2013) Sniffing on microbes: diverse roles ofmicrobial volatile organic compounds in plant health. Mol Plant MicrobeInteract 26:835843Borjesson T, Stollman U, Schnurer J (1992) Volatile metabolites produced by sixfungal species compared with other indicators of fungal growth on storedcereals. Appl Environ Microbiol 58:25992605Bradow JM, Connick WJ (1990) Volatile seed germination inhibitors from plantresidues. J Chem Ecol 16:645666Chiron N, Michelot D (2005) Odeurs de champignons: chimie et rle dans lesinteractions biotiques- une revue. Cryptogam Mycol 26:299364Cho IH, Namgung H-J, Choi H-K, Kim YS (2008) Volatiles and key odorants in thepileus and stipe of pine-mushroom (Tricholoma matsutake Sing). Food Chem106:7176Claeson AS, Levin JO, Blomquist G, Sunesson AL (2002) Volatile metabolites frommicroorganisms grown on humid building materials and synthetic media.J Environ Monit 4:667672Davis TS, Crippen TL, Hofstetter RW, Tomberlin JK (2013) Microbial volatileemissions as insect semiochemicals. J Chem Ecol 39:840859Farag MA, Ryu CM, Sumner LW, Par PA (2006) GC-MS SPME profiling or rhizobacterialvolatiles reveals prospective inducers of growth promotion and induced systemicresistance in plants. Phytochemistry 67:22622268Fraatz MA, Zorn H (2010) Fungal Flavours. In: Hofrichter M (ed) The Mycota X:Industial Applications, 2nd edition. Springer-Verlag, Berlin, pp 249264French RC, Gale AW, Graham CL, Latterell FM, Schmitt CG, Marchetti MA, RinesHW (1975) Differences in germination response of spores of several speciesof rust and smut fungi to nonanal, 6-methyl-5-hepten-2-one, and relatedcompounds. J Agric Food Chem 23:766770Herrmann A (2010) The chemistry and biology of volatiles. Wiley, ChichesterHolm RE (1972) Volatile metabolites controlling germination in buried weedseeds. Plant Physiol 30:293297Hung R, Lee S, Bennett JW (2013) The effect of low concentrations of thesemiochemical 1-octen-3-ol on Arabidopsis thaliana. Fungal Ecol 6:1926Hung R, Lee S, Bennett JW (2014) The effects of low concentrations of theenantiomers of mushroom alcohol (1-octen-3-ol) on Arabidopsis thaliana.Mycology: Int J Fungal Biol 5:7380Jelen HH, Wasowicz E (1998) Volatile fungal metabolites and their relation to thespoilage of agricultural commodities. Food Rev Int 14:391426Jing H, Sturre MJG, Hille J, Dijkwel PP (2002) Arabidopsis onset of leaf deathmutants identify a regulatory pathway controlling leaf senescence. Plant J32:5163Kinderlerer J (1989) Volatile metabolites of filamentous fungi and their role infood flavor. J Appl Bacteriol Symp Suppl. 67:133S144SHung et al. AMB Express 2014, 4:53 Page 6 of 7http://www.amb-express.com/content/4/1/53Kishimoto K, Matsui K, Ozawa R, Takabayashi J (2007) Volatile 1-octen-3-ol inducesa defensive response in Arabidopsis thaliana. J Gen Plant Pathol 73:3537Koornneef M, Bentsink L, Hilhorst H (2002) Seed dormancy and germination. CurrOpin Plant Biol 5:3336Korpi A, Jarnberg J, Pasanen A-L (2009) Microbial volatile organic compounds.Crit Rev Toxicol 39:139193Kuske M, Romain A-C, Nicolas J (2005) Microbial volatile organic compounds asindicators of fungi. Can an electronic nose detect fungi in indoor environments?Build Environ 40:824831Lee S, Hung R, Schink A, Mauro J, Bennett JW (2014) Phytotoxicity of volatileorganic compound. Plant Grow Reg. doi:10.1007/s10725-014-9909-9Lugtenberg B, Kamilova F (2009) Plant-growth-promoting rhizobacteria. AnnuRev Microbiol 63:541556Macias-Rubalcava ML, Hernandez-Bautista BE, Oropeza F, Duarte G, Gonzalez MC,Glenn AE, Hanlin RT, Anaya AL (2010) Allelochemical effects of volatilecompounds and organic extracts from Muscodor yucatanensis, a tropicalendophytic fungus from Bursera simaruba. J Chem Ecol 36:11221131Matysik S, Herbarth O, Mueller A (2008) Determination of volatile metabolitesoriginating from mould growth on wall paper and synthetic media.J Microbiol Methods 75:182187Mburu DM, Ndungu MW, Maniania NK, Hassanali A (2011) Comparison of volatileblends and gene sequences of two isolates of Metarhizium anisopliae ofdifferent virulence and repellency toward the termite Macrotermesmichaelseni. J Exp Biol 214:956962Minerdi D, Bossi S, Gullino ML, Garibaldi A (2009) Volatile organic compounds: apotential direct long-distance mechanism for antagonistic action of Fusariumoxysporum strain MSA 35. Environ Microbiol 11:844854Minerdi D, Bossi S, Maffei ME, Gullino ML, Garibaldi A (2011) Fusarium oxysporumand its bacterial consortium promote lettuce growth and expansin A5 geneexpression through microbial volatile organic compound (MVOC) emission.FEMS Microbiol Ecol 76:342351Morath SU, Hung R, Bennett JW (2012) Fungal volatile organic compounds: areview with emphasis on their biotechnological potential. Fungal Biol Rev26:7383Ogura T, Sunairi M, Nakajima M (2000) 2-Methylisoborneol and geosmin, themain sources of soil odor, inhibit the germination of Brassicaceae seeds.Soil Sci 46:217227Palta JP (1990) Leaf chlorophyll content. Remote Sens Rev 5:207213Paul D, Park KS (2013) Identification of volatiles produced by Cladosporiumcladosporioides CL-1, a fungal biocontrol agent that promotes plant growth.Sensors 13:1396913977Rohlfs M, Obmann BR, Petersen R (2005) Competition with filamentous fungi andits implication for a gregarious lifestyle in insects living on ephemeralresources. Ecol Entomol 30:556563Ryu C-M, Farag MA, Hu C-H, Reddy MS, Wei H-X, Par PW, Kloepper JW (2003)Bacterial volatiles promote growth in Arabidopsis. Proc Natl Acad Sci U S A100:49274932Sahlberg B, Gunnbjrnsdottir M, Soonc A, Jogi R, Gislason T, Wieslander G,Janson C, Norback D (2013) Airborne molds and bacteria, microbial volatileorganic compounds (MVOC), plasticizers and formaldehyde in dwellings inthree North European cities in relation to sick building syndrome (SBS).Sci Total Environ 444:433440Schnrer J, Olsson J, Borjesson T (1999) Fungal volatiles as indicators of food andfeeds spoilage. Fungal Genet Biol 27:209217Splivallo R, Novero M, Bertea CM, Bossi S, Bonfante P (2007) Truffle volatilesinhibit growth and induce an oxidative burst in Arabidopsis thaliana. NewPhytol 175:1724Steinkraus KH (1983) Industrial Applications of Oriental Fungal Fermentations. In:Smith JE, Berry DR, Kristiansesn B (ed) The Filamentous Fungi Vol. 4 FungalTechnology. Edward Arnold, London, pp 171189Strobel GA, Dirkse E, Sears J, Markworth C (2001) Volatile antimicrobials fromMuscodor albus, a novel endophytic fungus. Microbiology 147:29432950Sunesson A-L, Vaes WHJ, Nilsson C-A, Blomquist GR, Andersson B, Carlson R(1995) Identification of volatile metabolites from five fungal species cultivatedon two media. Appl Environ Microbiol 61:29112918Takken W, Knols BG (1999) Odor-mediated behavior of Afrotropical malariamosquitoes. Annu Rev Entomol 44:131157Thakeow P, Angeli S, Weibecker B, Schtz S (2008) Antennal and behavioralresponses of Cis boleti to fungal odor of Trametes gibbosa. Chem Senses33:379387Turner WB, Aldridge DC (1983) Fungal Metabolites II. Academic Press, LondonVan Loon LC, Bakker PAHM, Pieterse CMJ (1998) Systemic resistance induced byrhizosphere bacteria. Annu Rev Phytopathol 36:453483Vespermann A, Kai M, Piechulla B (2007) Rhizobacterial volatiles affect the growthof fungi and Arabidopsis thaliana. Appl Environ Microbiol 73:56395641Wang X, Sun C, Gao S, Wang L, Shuokui H (2001) Validation of germination rateand root elongation as indicator to assess phytotoxicity with Cucumis sativus.Chemosphere 44:17111721Wenke K, Kai M, Piechulla B (2010) Belowground volatiles facilitate interactionsbetween plant roots and soil organisms. Planta 231:499506Wenke K, Weise T, Warnke R, Valverde C, Wanke D, Kai M, Piechulla B (2012)Bacterial Volatiles Mediating Information Between Bacteria and Plants. In:Witzany G, Baluska F (ed) Biocommunication of Plants. Springer-Verlag, Berlin,pp 327347doi:10.1186/s13568-014-0053-8Cite this article as: Hung et al.: Common gas phase molecules fromfungi affect seed germination and plant health in Arabidopsis thaliana.AMB Express 2014 4:53.Submit your manuscript to a journal and benet from:7 Convenient online submission7 Rigorous peer review7 Immediate publication on acceptance7 Open access: articles freely available online7 High visibility within the eld7 Retaining the copyright to your articleSubmit your next manuscript at 7 springeropen.comHung et al. AMB Express 2014, 4:53 Page 7 of 7http://www.amb-express.com/content/4/1/53