Effect of fungal community and diversity on Norway spruce decomposition

Transkriptio

1 Effect of fungl community nd diversity on Norwy spruce decomposition Lr Vlentín 1 Tiin Rjl 1, Mikko Peltoniemi 1, Jussi Heinonslo 2, Tin Pennnen 1, Ris Mäkipää 1 1 Metl, Vnt Unit 2 Dpt Food nd Environmentl Sciences, University of Helsinki Seminr on Forest ecology nd chllenges in the forest modelling 15 th December 11, Metl

2 "Succession nd diversity of wood inhbiting fungi during decomposition of ded wood " Does fungl diversity dilution ffect the wood decomposition? Does fungl community composition of different decy stge ffect wood decomposition? How enzyme ctivities chnge in reltion to fungl diversity nd community composition? Wht bout in reltion to decomposition?

3 Wood smples: 46 fllen logs from unmnged Norwy spruce forest from Lpinjärvi

4 Effect of fungl diversity dilution on spruce decomposition Experimentl set up Decy clss of swdust I = erly decy II = medium decy III = lte decy Non sterile Inocul I II III Sterile substrte I II III Microcosm 1 Dilution of swdust I Microcosm 2 Dilution of swdust II Microcosm 3 Dilution of swdust III ND = non diluted inoculum 1 1 = dilution of 1-1 g of inoculum/g of substrte (dm) 1 2 = dilution of 1-2 g of inoculum/g of substrte (dm) Ctrl = sterile substrte (2 times 121 C for min, 3-dy intervl)

5 Fungl functionlity ssessed by mesuring the respirtion ctivity nd wood degrding enzyme ctivities. Erly decy Medium decy Lte decy Anlysis Respirtion ctivity Incubtion t 21 ºC for 17 weeks wood degrding enzymes Incubtion t 21 ºC for 13 weeks 3 microcosms x 4 tretments x 3 replictes = 36 bottles 3 microcosms x 4 tretment x 3 replictes = 36 bottles CO 2 production DNA extrction nd 17 weeks Enzyme nlysis 17 weeks DNA Extrction, 9 nd 13 weeks Enzyme nlysis 4, 6, 9, 11 nd 13 weeks

6 Wood decomposition: Weekly produced CO 2 mesured by gs chromtogrphy. Replcement of ir by evcution system with moist ir to prevent O 2 depletion nd drought. % C loss = (Cumulted CO 2 /Mx CO 2 ) x 1 Mx CO 2 = mss swdust (g) x %C x M CO2 /M C

7 Activities of lignocellulose modifying enzymes: Two cellulose degrding enzymes: glucosidse, cellobiohydrolse. Two hemicellulose degrding enzymes: glucuronidse, xylosidse. Lignin modifying enzyme: lccse. Extrction by filter centrifugtion method. Hydrolytic enzymes mesured by fluorimetric ssy using methylumbelliferone substrtes. Lccse mesured by colorimetric ssy following the oxidtion of ABTS. 5 μl tube filter 2 ml micro centrifuge tube

8 DNA nlysis of fungl community: Totl DNA extrction using commercil kit NucleoSpin 96 Soil Kit. Fungl DNA mplifiction by Polymerse Chin Rection (PCR) with primers pir GC ITS1F nd ITS2. DNA seprtion by denturing grdient gel electrophoresis (DGGE). Bnds in the gel were nlyzed by GelCompr II softwre. A bnd in the gel represents n Opertionl Txonomic Unit (OTU). Source: Mcherey Ngel

9 Results Influence of fungl diversity

10 Fungl diversity decresed by diluting the inoculum with the substrte. Non diluted inocul Control 1 1 diluted inocul 1 2 diluted inocul L LIII II I III II I III L II I III II I

11 OTUs number increses in reltion with decy stge. Grdul reduction of OTUs due to dilution of inoculum. After incubtion fungl diversity increses. C loss nd OTUs increse in reltion with wood decy stge. Diversity t beginning Diversity t end (16 weeks) 4 Crbon loss (16 weeks) OTUs OTUs Crbon loss % ND 1/1 1/1 Ctrl ND 1/1 1/1 Ctrl ND 1/1 1/1 Ctrl Erly decyed swdust Middle decyed swdust Lte decyed swdust Microcosms

12 Influence of decy stge nd inoculum dilution on CO 2 production: No cler dilution effect on decomposition for erly nd lte decyed swdust. Dilution of medium decyed swdust ffects spruce decomposition. Cum CO 2 mg/g Erly decy b b b Medium decy Time (dys) b b c Lte decy b ND = non diluted inoculum 1 1 = dilution of 1 1 of inoculum 1 2 = dilution of 1 2 of inoculum Ctrl = control: sterile substrte CO 2 levels mrked with the sme letter re not different ccording to Tukey s test (P <.5).

13 Totl hydrolytic ctivity in medium decyed swdust: Activities lower thn 3 pkt/g. β glucuronidse ctivity levels were the highest (dt not shown). Downwrd trend towrds the end of incubtion. 25 Medium decy Activity (pkt/g) ND = non diluted inoculum 1 1 = dilution of 1 1 of inoculum 1 2 = dilution of 1 2 of inoculum Ctrl = control: sterile substrte Time (weeks)

14 Reltionship of crbohydrte degrding ctivity nd wood decomposition: Role of hydrolytic enzymes on the initil phse of decomposition Hydrolytic ct/cum CO erly decy middle decy lte decy Time (weeks)

15 Chnges of of fungl community structure long the incubtion

16 Conclusions Decomposition incresed long with number of fungl tx (OTUs) nd decy clss of the wood. Dilution decresed fungl diversity, but number of OTUs recovered long with the incubtion. The effect of fungl diversity reduction on wood decomposition ws only cler for middle decyed swdust. Fungl diversity reduction did not reflect chnges in enzyme production, only lccse ctivity incresed in reltion with decy.

17 Prt 2 Does fungl community composition of different decy stge ffect wood decomposition?

18 Experimentl set up Effect of species composition Microcosm 1 Erly decyed substrte+ different inocul Erly decyed inoculum (I) hs less effect on substrtes decomposition thn medium (II), lte (III) or mix inocul (M) hve. Microcosm 2 Medium decyed substrte + different inocul Microcosm 3 Lte decyed substrte + different inocul Lte decyed substrte Medium decyed substrte Erly decyed substrte

19 Spruce decomposition depending on the community composition Cum CO 2 mg/g Erly decyed subsrte + different inoculum Medium decyed substrte + different inoculum Time (dys) b Lte decyed substrte + different inoculum b Erly decyed inoculum Lte decyed inoculum Medium decyed inoculum Mixture of inocul

20 Contributing to the study: Lbortorimestri Stu Repo (Experimentl set up, CO 2, evcution, enzymes, chemicl nlysis), Krin Pynnönen (preprtion of swdust smples). Trinees: Riikk Mäkelä (Enzymes, CO 2, DNA nlysis), Mtis Häyrynen (DNA nlysis), Srit Nukkrinen (upcoming DNA nlysis). Funding by Acdemy of Finlnd.

21 Kiitos

22 Totl hydrolytic ctivity in diversity dilution experiment: Activities lower thn 3 pkt/g. Similr levels mong swdust clss nd mong dilutions. Exceptions: Inoculum dilution 1 2 of swdust I nd III. Slight downwrd trend towrds the end of incubtion Activity (pkt/g) Time (weeks) Microcosms 1 Dilution of swdust I Time (weeks) Microcosms 2 Dilution of swdust II Time (weeks) Microcosms 3 Dilution of swdust III

23 After 17 weeks of incubtion, number of species nd CO2 production re relted

24 Experiment of funglcommunitycomposition OTUs hd low vrition. OTUs number slightly incresed towrds the end of incubtion in some microcosms. Inoculum from swdust I hd less effect on decomposition si + ii si + iii si + iiii si + im sii + ii sii + iii sii + iiii sii + im siii + ii siii + iii siii + iiii siii + im OTUs C loss % Microcoms