143Taiwan J For Sci 17(2): 143-53, 2002

Research paper

Survival of Four Ganoderma Species and Several Wood-

inhabiting Fungi in Different Soil Matrix Potentials

Tun-Tschu Chang,1,3) Meing-Ling Wu,1) Chuen-Hsu Fu,1) Chao-Hsien Fu2)

Summary

The survival of Ganoderma australe, G. boninense, G. lucidum and G. weberianummycelia, and of Ganoderma-colonized wood was measured in soils with different soil matrixpotentials. G. australe and G. boninense producd no chlamydospores, while G. lucidum andG. weberianum did. Mycelia of G. australe and G. boninense buried in the -0.025 MPa soilmoisture treatment declined rapidly and could not be recovered at 9 and 12 wk, respectively.Mycelia buried in the -0.50 MPa soil moisture treatment had relatively higher recovery ratesat the same incubation times compared with those in the higher soil moisture treatments.However, mycelia were not recovered at 15 wk in any treatment. Survival of G. lucidum and G.weberianum mycelia in all soil moisture treatments rapidly declined from 0 to 15 wk afterincubation. However, survival of mycelia consistently ranged from 35% to 50% at 15 to 52 wkafter incubation. These results indicate that chlamydospores in soil play an important role inthe long-term survival of Ganoderma species when mycelia are not harbored in woody debris.G. australe and G. boninense were not recovered from pieces of artificially infested woodsubjected to 1 and 3 mo of flooding, respectively. In treatments with the lower soil moisture,the survival of these 2 fungi ranged from 80% to 90% over 2 yr. In all soil moisture treatments,G. lucidum and G. weberianum ranged from 80% to more than 90% over 2 yr. These resultsindicate that, regardless of chlamydospore formation, woody debris in soils harboringGanoderma species plays an important role in the long-term survival of the fungi, andchlamydospores of Ganoderma in woody debris enhance the resistance of the fungi toenvironmental stress such as flooding. Seven species of other wood-inhabiting fungi which donot produce chlamydospores were not recovered from pieces of artificially infested woodsubjected to 1 or 5 mo of flooding. In a treatment with a lower soil moisture (-0.50 MPa), thesurvival of these 7 fungi ranged from 70% to more than 90% over 2 yr. However, the survivalof others that produced chlamydospores ranged from 70% to more than 90% in soils with-0.50 MPa and flooding. These results are similar to those for Ganoderma species and indicatethat chlamydospores of wood-inhabiting fungi and woody debris play an important role in theirlong-term survival and in their resistance to environmental stresses such as flooding. Flood-ing infested fields may help control wood-inhabiting fungi which do not produce

1) Division of Forest Protection, Taiwan Forestry Research Institute. 53 Nanhai Rd., Taipei 100, Taiwan.

100 532) Lienhuachih Station of the Taiwan Forestry Research Institute. PO Box 5, Yuchi 555, Nantao County, Taiwan.

555 53) Corresponding author.

Received January 2002, Accepted March 2002. 2002 1 2002 3

144 Chang et al. Survival of Ganoderma and wood inhabiting fungi in soil

chlamydospores, but may have little effect on those which produce chlamydospores in thefield.Key words: Ganoderma, wood-inhabiting fungi, survival, disease management.Chang TT, Wu ML, Fu CH, Fu CH. 2002. Survival of four Ganoderma species and several

wood-inhabiting fungi in different soil matrix potentials. Taiwan J For Sci:17(2)143-53.

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INTRODUCTIONG a n o d e r m a ( B a s i d i o m y c o t a :

Ganodermatales) is a genus of wood-inhab-iting fungi distributed around the world fromtropical to temperate habitats on monocots,

dicots, and gymnosperms (Sinclair et al.1987). Some species are only saprophytic,but several are pathogens that cause decayin roots, butts, and trunks of living trees and

145Taiwan J For Sci 17(2): 143-53, 2002

the slow decline of host species. Four spe-cies of Ganoderma, i.e., G. australe, G.boninense, G. lucidum, and G. weberianum,are common pathogens in Taiwan that causedecay and slow decline of numerous orchardand forest tree species (Chang et al. 1999).Several slowly expanding, circular diseasepatches extending from infection centerswere observed in the field indicating that thedisease caused by Ganoderma is spreadfrom diseased to healthy trees by root con-tact (Bakshi et al. 1976, Adaskaveg andGilbertson 1987). Infested root debris mayplay an important role as primary inoculumand for the long-term survival of the fungi.Airborne basidiospores can also initiate newinfections on freshly cut stumps and caninfest logging debris with subsequent spread

to live trees by root contact (Turner 1965,Darus et al. 1996, Sanderson and Pilotti1997).

In culture studies, abundant chlamy-dospores have been produced in pure cul-ture and woody debris for some species ofGanoderma such as G. lucidum and G.weberianum, while others such as G.australe and G. boninense, produced nochlamydospores (Chang et al. 1996). Therole of chlamydospores in the propogationof Ganoderma is unknown, and the long-term survival of chlamydospores and myce-lia in the soil has not been previouslydocumented. In this study, the survival ofGanoderma chlamydospores and myceliaand Ganoderma in artificially infestedwoody debris was assessed in soils with

Table 1. List of isolates of the test fungi

Fungus and culture no.1) Chlamydospores2) Arthroconidia3)

Ganoderma australe TFRI 545Ganoderma boninense TFRI 129Ganoderma lucidum TFRI 870Ganoderma weberianum TFRI 869Abortiporus biennis TFRI 274Bjerkandera adusta TFRI 180Coriolus brevis TFRI 552Daedalea dickinsii TFRI 305Favolus spatulatus TFRI 326Fomitopsis cajanderi TFRI 102Inonotus rickii TFRI 712Perenniporia formosana TFRI 375Perenniporia latissima TFRI 281Phaeolus schweinitzii TFRI 434Polyporus arcularis TFRI 597Rigidoporus ulmarius TFRI 763Phellinus longisetulosus TFRI 201Schizopora flavipora TFRI 401Trametes hirsuta TFRI 211Trametes versicolor TFRI 311) Isolates of the test fungi were isolated and identified by the 1st author.2) : Presence of chlamydospores in the culture; : absence of chlamydospores from the culture.3) : Presence of arthroconidia in the culture; : absence of arthroconia from the culture.

146 Chang et al. Survival of Ganoderma and wood inhabiting fungi in soil

varying moisture levels. In addition, thesurvival of some other wood-inhabitingfungi in artificially infested woody debriswas studied.

MATERIALS AND METHODS

Fungal isolates, soils, and selective mediaDetails of fungal isolates used in this

study are given in Table 1. All fungal iso-lates were collected from fruiting bodiesand identified by the 1st author. For obser-vation of chlamydospores in fungal cultures,the fungi were grown on malt-extract agar(MEA) medium (2% malt extract, 2% agar)at 25 for 4 wk before microscopicexamination. The silt loam soil used for thisstudy was collected from a natural forest inTaipei. Initially, it consisted of 36.7% sand,52.6% silt, and 10.7% clay, and had about a10% moisture content (-0.42 MPa). Fortreatments requiring less than 10% soilmoisture, the soil was dried at 40 untilthe desired moisture content was reached.For treatments requiring more than 10%soil moisture, distilled water was added tothe soil until the desired moisture contentwas reached. The soil matrix potential wasadjusted gravimetrically by comparison witha soil moisture retention curve. In a prelimi-nary test, the selective medium (Chang1995) developed for Phellinus noxius wasdetermined to be suitable for the fungi usedin this study. The selective medium con-sisted of 20 g of malt extract, 20 g of agar,10 mg of benomyl, 10 mg of dicloran, 100mg of ampicillin, and 500 mg of gallic acidper liter. The temperature range was between15 and 33 during the experimental periodin the greenhouse.

Survival of Ganoderma mycelia andchlamydospores in soil

Soil matrix potentials were adjusted to-0.50, -0.20, and -0.025 MPa, respectively,and soils were placed in separate plasticco nta ine rs (1 5 cm high 15 cm indiameter). Pieces of cellophane (2 2 cm)colonized by Ganoderma lucidum , G.boninense, G. weberianum, and G. australemycelia were placed on MEA medium for 3wk at 25 . In addition to mycelia, chlamy-dospores were present on pieces of cello-phane for G. weberianum and G. lucidum.Well-colonized cellophane was buried 5 cmbelow the soil surface and each plastic con-tainer was covered with aluminum foil. Totest mycelial and chlamydospore survival,pieces of cellophane were carefully re-moved from the soil, placed on the selec-tive medium, and incubated at 25 . Threereplicate containers were used for each soilmoisture level. Thirty pieces of cellophanewere used for each replicate. Survival ofmycelia and chlamydospores was calculatedas the percentage of colonized pieces ofcellophane from which the tested fungiemerged after 2 wk of incubation. This ex-periment was performed twice.

Survival of Ganoderma in infested woodin soil

Wood sections (about 3 to 5 cm ind i a m e t e r a n d 1 0 c m i n l e n g t h ) o fCinnamomum camphora (L.) Nees etEberm. were artificially infested with the 4tested Ganoderma species 2 mo before thes ta r t o f the exper iment . Ganod ermalucidum, G. boninense, G. weberianum andG. australe completely colonized the woodsections in 2 mo at 25oC. The soil matrixpotential was adjusted to -0.50, -0.30, or-0.10 MPa, or the soil was flooded withwater. Eighty-centimeter-high columns ofeach soil type were placed in separate plas-tic containers (100 cm high 40 cm in

147Taiwan J For Sci 17(2): 143-53, 2002

diameter) and wood sections were buried 15cm below the soil surface. The cap wassealed with plastic tape to maintain constantsoil moisture. One container for each soilmoisture treatment was used. Three woodsections (replicates) were used in the iso-lation for each treatment. When wood sec-tions were used to test for fungi survival,they were washed with tap water and blotteddry. Fifty wood fragments (about 3 6 mm)were cut from each wood section and placedon selective medium at 25 . Survival ininfested wood was calculated as the percent-age of wood fragments from which thet es t ed fungi emerged a f te r 2 wk ofincubation. This experiment was conductedtwice.

Survival of other fungi in infested woodin soil

Wood sections (about 3 to 5 cm indiameter and 10 cm in length) of C.camphora were artificially infested with 16tested fungi, in addition to those Ganodermaspecies listed in Table 1, 2 mo before thestart of the experiment. These 16 wood-in-habiting polypore fungi completely colo-nized the wood sections in 2 mo at 25oC.The soil matrix potential was adjustedto -0.50 MPa, or the soil was flooded withwater. Eighty-centimeter-high columns ofeach soil type were placed in separate plas-tic containers (100 cm high 40 cm indiameter), and wood sections were buried15 cm below the soil surface. Each cap wassealed with plastic tape to maintain a con-stant soil moisture. One container for eachsoil moisture treatment was used. Threewood sections (replicates) were used in theisolation for each treatment. When woodsections were used to test fungal survival,they were washed with tap water and blotteddry. Fifty wood fragments (about 3 6

mm) were cut from each wood section andplaced on the selective medium at 25oC.Survival in infested wood was calculated asthe percentage of wood fragments fromwhich the test fungi emerged after 2 wk ofincubation. This experiment was conductedtwice.

Statistical analysesSince variances between 2 repeated tri-

als in all experiments were not significant(p = 0.05) by SAS analysis of variance(ANOVA) (SAS Institute, Cary, NC), datafrom each of the 2 repeated trials werepooled. SAS repeated-measures analysis(SAS Institute) Cary was used for statisti-cal analyses. Survival (%) of mycelia andinfested wood was transformed to arcsin[square root (survival/100)] before ANOVA.The significance of the response of the soilmatrix potential at each incubation time wasanalyzed by the least significant difference(LSD) test if the ANOVA F test wassignificant. The mult ivar iate ANOVA(Wilks, lambda F test) was used to analyzesignificant trends for soil matrix potentialresponses.

RESULTS

Survival of Ganoderma mycelia in soilTrends for mycelial survival of G.

australe and G. boninense with time weresignificant among soil matrix potentialtreatments (p = 0.01), and there were sig-nificant differences (p = 0.01) among soilmatrix potential treatments at 6 individualincubation times (Fig. 1A,B). Mycelia bur-ied in the -0.025MPa soil moisture treat-ment decline most rapidly and could not berecovered at 9 and 12 wk for G. australeand G. boninense, respectively. Myceliaburied in the -0.50MPa soil moisture treat-

148 Chang et al. Survival of Ganoderma and wood inhabiting fungi in soil

ment had relatively higher recovery rates atthe same incubation times compared withthose in the -0.20MPa and -0.025MPa soilmoisture treatments. However, myceliawere not recovered at 15 wk in any of thesetreatments. The LSD test among all treat-ments at different incubation times differed

significantly (p = 0.01) for G. australe andG. boninense.

The soil matrix potential had signifi-cant effects (p = 0.05) on mycelia survivalof G. lucidum and G. weberianum with timeamong soil matrix potential treatments (Fig.1C,D). There were significant differences

Fig. 1. Survival of mycelia of 4 Ganoderma species buried in soils with various soil moisturetreatments for different incubation times. Each point is the mean of 6 replicates. Survival of myce-lia was calculated as the percentage of colonized cellophane pieces from which the fungi emergedafter 2 wk of incubation. Means for each incubation time followed by the same letter do not sig-nificantly differ according to the least significant difference test (p� 0.01). The multivariateanalysis of variance showed that trends among soil matrix potential treatments with time signifi-cantly differed p� 0.01 for G. australe and G. boninense. The multivariate analysis of varianceshowed that trends among soil matrix potential treatments with time significantly differed at p�0.05 from 0 to 15 weeks after incubation and did not significantly differ at p� 0.05 from 18 to 52wk for G. lucidum and G. weberianum. A: G. australe, B: G. boninense, C: G. lucidum , D: G.weberianum.

149Taiwan J For Sci 17(2): 143-53, 2002

(p = 0.01) among soil matrix potential treat-ments from 0 to 15 wk after incubation, butthere were no significant differences (p =0.05) among soil matrix potential treatmentsfrom 18 to 52 wk after incubation. Survivalof mycelia in all soil moisture treatmentsrapidly declined from 0 to 15 wk after

incubation. However, survival of myceliaconsistently ranged from 35% to 50% after18 wk of incubation. The LSD test amongall treatments at different incubation timesdid not significantly differ (p = 0.05) for G.lucidum and G. weberianum except for G.lucidum at 3 wk.

Fig. 2. Survival of 4 Ganoderma species in artificially infested wood sections buried in soils withvarious soil moisture treatments for different incubation times. Each point is the mean of 6replicates. Survival in infested wood was calculated as the percentage of wood fragments fromwhich the fungi emerged after 2 wk of incubation. Trends among all treatments with time did notsignificantly differ (p = 0.05) when flooding treatment was excluded, but significantly differed (p= 0.01) when flooding treatment was included by the multivariate analysis of variance for G. australeand G. boninense. Trends among all treatments with time did not significantly differ (p = 0.05) bythe multivariate analysis of variance for G. lucidum and G. weberianum . A: G. australe, B: G.boninense, C: G. lucidum, D: G. weberianum.

150 Chang et al. Survival of Ganoderma and wood inhabiting fungi in soil

Survival of Ganoderma in infested woodG. australe and G. boninense were not

recovered from pieces of artifically in-fested wood subjected to 1 and 3 mo offlooding, respectively. However, in treat-ments with lower soil moisture, G. australeand G. boninense survival ranged from 80%to more than 90% over 2 yr (Fig. 2A,B).Trends for survival of infested wood withtime did not significantly differ (p = 0.05)among all treatments when flooding treat-ment was excluded, but significantly differ(p = 0.01) when flooding treatment wasincluded. The LSD test among all treatmentsat different incubation times when the flood-ing treatment was excluded did not signifi-cantly differ (p = 0.05) for G. australe andG. boninense.

Trends for survival of infested woodwith time did not significantly differ amongal l t reatments for G. lucidum and G.

weberianum. In all soil moisture treatmentsincluding flooding, G. lucidum and G.weberianum survival ranged from 80% tomore than 90% over 2 yr (Fig. 2C,D). TheLSD test among all treatments at differentincubation times did not significantly dif-fer (p = 0.05).

Survival of other fungi in infested woodin soil

Survival of 16 wood-inhabiting fungi insoils with -0.50MPa soil matrix ranged from70% to 100% over 2 yr (Table 2). For eachspecies, the LSD test at different incubationt imes was not significant (p = 0.05).However, when these fungi in infested woodwere placed in soils with flooding, 4 ofthem, i.e., Bjerkandera adusta, Favolusspatulatus, Phellinus longisetulosus, andTrametes versicolor, and 3 of them, i.e.,Abortiporus biennis, Schizopora flavipora,

Table 2. Survival (%) of some wood-inhabiting fungi in artificially infested wood sectionsburied in soils with -0.50MPa soil matrix potential for different incubation times

Time after incubation (mo)Fungus and culture no.

1 5 12 24

Aboriporus biennis TFRI 274 90 85 80 85

Bjerkandera adusta TFRI 180 80 85 85 75

Coriolus brevis TFRI 552 95 85 90 80

Daedalea dickinsii TFRI 305 85 85 90 75

Favolus spatulatus TFRI 326 85 100 80 80

Fomitopsis cajanderi TFRI 102 100 90 90 85

Inonotus rickii TFRI 712 90 80 85 75

Perenniporia formosana TFRI 375 85 90 80 80

Perenniporia latissima TFRI 281 100 85 80 80

Phaeolus schweintzii TFRI 434 95 100 80 75

Polyporus arcularis TFRI 597 95 85 70 85

Rigidoporus ulmarius TFRI 763 80 75 70 70

Phellinus longisetulosus TFRI 201 90 95 80 70

Schizopora flavipora TFRI 401 85 80 75 90

Trametes hirsuta TFRI 211 95 85 90 70

Trametes versicolor TFRI 31 95 90 70 80

151Taiwan J For Sci 17(2): 143-53, 2002

and Trametes hirsuta, were not recoveredfrom pieces of artificially infested woodsubjected to 1 and 5 mo of treatment, re-spectively (Table 3). The survival of theremaining fungi which produced chlamy-dospores ranged from 70% to 100% over 2yr. For these fungi, the LSD test at differ-ent incubation times did not significantlydiffer (p = 0.05) for each species.

DISCUSSIONWoody debris infested with Gan-

oderma australe, G. boninense, G. lucidum,and G. weberianum in soil played an impor-tant role in the long-term survival of thesefungi. In addition, woody debris-infestingG. lucidum and G. weberianum which pro-duced chlamydospores were able to survivewith an environmental stress such as

flooding. Mycelia-producing chlamy-dospores of G. lucidum and G. weberianumin soils with different soil matrix potentialssurvived over 52 wk after incubation, butmycelia of G. australe and G. boninensewhich did not produce chlamydospores sur-vived only up to 12 wk after incubation.These results led to the conclusion thatwoody debris infested with Ganodermaspecies, regardless of chlamydosporeproduction, plays an important role in thelong-term survival of these fungi in the soil.However, for those species which are ableto produce chlamydospores, mycelia alsoplay an important role in the long-term sur-vival in soil. In addition, Ganoderma spe-cies which produce chlamydospores in in-fested woody debris have the ability to re-sist environmental stress such as flooding.

Table 3. Survival (%) of some wood-inhabiting fungi in artificially infested wood sections

buried in soils with flooding for different incubation times

Time after incubation (mo)Fungus and culture no. Chlamydospores1)

1 5 12 24

Aboriporus biennis TFRI 274 – 20 0 0 0

Bjerkandera adusta TFRI 180 – 0 0 0 0

Coriolus brevis TFRI 552 + 90 85 80 85

Daedalea dickinsii TFRI 305 + 85 90 85 90

Favolus spatulatus TFRI 326 – 0 0 0 0

Fomitopsis cajanderi TFRI 102 + 100 85 75 80

Inonotus rickii TFRI 712 + 85 90 70 85

Perenniporia formosana TFRI 375 + 100 100 85 90

Perenniporia latissima TFRI 281 + 100 95 100 85

Phaeolus schweintzii TFRI 434 + 100 85 95 90

Polyporus arcularis TFRI 597 + 95 85 85 80

Rigidoporus ulmarius TFRI 763 + 80 80 75 70

Phellinus longisetulosus TFRI 201 – 0 0 0 0

Schizopora flavipora TFRI 401 – 25 0 0 0

Trametes hirsuta TFRI 211 – 20 0 0 0

Trametes versicolor TFRI 31 – 0 0 0 01) +: Presence of chlamydospores in the culture; –: absence of chlamydospores from the culture.

152 Chang et al. Survival of Ganoderma and wood inhabiting fungi in soil

In this study, survival of the 16 other wood-inhabiting fungi showed similar results tothose of the 4 Ganoderma species. Theseresults demonstrate that chlamydospores ofwood-inhabiting fungi play an important rolein the long-term survival and in the resis-tance to environmental stress such as flood-ing in soil. Similar results were reported forwoody debris infested with Phell inusnoxius, but not mycelia, which did not pro-duce chlamydospores in which the debrisplayed an important role in the long-termsurvival of the fungus in soil; furthermorethe fungus was not recovered from infestedwood subjected to 1 mo of flooding (Chang1996). Arthroconidia are usually producedin some basidiomycete wood-inhabitingfungi (Stalpers 1978). Arthroconidia of P.noxius were not the surviving structure(Chang 1996). In this study, 4 species ofwood-inhabiting fungi produced arth-roconidia which were also not the survivingstructure.

Submerging wood in water has beenused to prevent postharvest colonization bywood-decay fungi (Rayner and Boddy 1988).This might have proved helpful because ofthe activities of anaerobic microorganisms.In this study, when the test fungi-colonizedwood sections which produced chlamy-dospores were submerged in water, the fungisurvived for over 2 yr. However, when thetest fungi-colonized wood sections whichdid not produce chlamydospores were sub-merged in water, the fungi died within 3 mo.When P. noxius-colonized wood sectionswhich did not produce chlamydospores weresubmerged in water, the fungus died within1 mo (Chang 1996). These results indicatethat submerging wood for prevention ofpostharvest colonization and woody debrisinfected with the root/butt rot fungi mightnot be effective for those fungi which pro-

duce chlamydospores. However, for dis-ease management of root/butt rot caused bywood-inhabiting fungi which do not producechlamydospores, flooding infested fields fora certain period of time might eliminate theinoculum source in infected wood and roots.However, field studies are required to testthis hypothesis.

LITERATURE CITEDAdaskaveg JE, Gilbertson RL. 1987. Infec-tion and colonization of grapevines byGanoderma lucidum. Plant Dis 71:251-3.Bakshi BK, Reddy MAR, Singh S. 1976.Ganoderma root rot mortality in khair (Acaciacatechu Willd.) in reforested stands. Eur J ForPathol 6:30-8.Chang TT. 1995. A selective medium forPhellinus noxius. Eur J For Pathol 25:185-90.Chang TT. 1996. Survival of Phellinusnoxius in soil and in the roots of dead hostplants. Phytopathology 86:272-6.Chang TT, Chiu WH, Hua J. 1996. Thecultural atlas of wood-inhabiting Aphy-llophorales in Taiwan (vol. 1). Taipei: FoodIndustry Research and Development Institute(Taiwan) Mycological Monograph 10. 248 p.Chang TT, Hsieh HJ, Chang RJ, Fu CS.1999. Common tree diseases in Taiwan. Taipei:Taiwan Forestry Research Institute TechnicalReport 98. 202 p. [in Chinese].Darus A, Seman IA, Azahari M. 1996. Spreadof Ganoderma boninense and vegetativecompatibility studies of a single field palmisolates. Proceedings of the PORIM Interna-tional Palm Oil Congress; Selangor, Malaysia.Kuala Lumpur: Palm Oil Research Institute ofMalaysia. P 317-29.Rayner ADM, Boddy L. 1988. Fungal decom-position of wood--its biology and ecology.New York: Wiley. 583 p.Sanderson FR, Pilotti CA. 1997. Ganoderma

153Taiwan J For Sci 17(2): 143-53, 2002

basal stem rot: an enigma, or just time torethink an old problem? Planter (KualaLumpur) 73:489-93.Sinclair WA, Lyon HH, Johnson WT. 1987.Diseases of trees and shrubs. Ithaca, NY andLondon: Cornell University Press. 575 p.

Stalpers JA. 1978. Identification of wood-inhabiting Aphyllophorales in pure culture.Studies in Mycology 16.Baarn: Cent-raalbureau voor Schimmelcultures. 248 p.Turner PD. 1965. Infection of oil palms byGanoderma. Phytopathology 55: 937.