1994-Biodiversity in arbuscular mycorrhizal fungi
- 格式:pdf
- 大小:2.17 MB
- 文档页数:11
Mycol.Res.
98(7):705-715(1994)PrintedinGreatBntain
REVIEW
Biodiversityinarbuscularmycorrhizalfungi
M.GIOVANNETTPANDV.GIANINAZZI-PEARSOW705
llstitutodiMicrobiologiaAgraria,CentrodiStudioperlaMicrobiologiadelSuolo,ViadelBorghetto80,
56124Pisa,Italy
2LaboratoiredePhytoparasitologie,INRA/CNRS,StationdeGinitiqueetd'AmiliorationdePlantes,INRA,BV1540,21034DijonCedex,France
Knowledgeandconservationofdiversityinsymbioticarbuscularmycorrhizalfungiisofcrucialimportancefortheirefficientusein
environmentalconservationandsustainableplantproductionsystems.Therecalcitranceofthesemicroorganismstopureculture,and
theabsenceofinformationaboutplasmogamy,karyogamyormeiosis,meansthatinformationaboutthegeneticalbasesofany
variationsintheirpopulationbiology,ecologicalspecificityorsymbioticactivityisgenerallylacking.Amultidisciplinaryapproachis
necessarytoidentifysignificantdifferencesbetweenpopulations,species
orisolates.Anoverviewispresentedofsomeofthe
morphological,biologicalandmolecularaspects
ofarbuscularmycorrhizalfungithatmaycontributetodefiningandunderstanding
biodiversityinthisgroupofsymbioticmicroorganisms.
Table
1.SomesourcesofbiodiversityinarbuscularmycorrhizalfungiBiodiversity,atermtodescribevariabilitybetweenorganisms
orpopulationsoforganisms,hasdifferentfacetsdependingon
thelevelofdiversityconsidered(species,population,eco-
system)ortheorganismsconcerned(Barbault,
1992).
Biodiversitycanbeexploitedinmanywaysatscientificlevels,
themostwellknownandthemostancientnodoubtbeingin
taxonomyandsystematics,andmorerecentlyforstudiesof
populationbiology,ofevolutionandconservationof
ecosystems,orforselectionofmaterialsforbiotechnology.
Theroleoffungiinthefunctioningandbiodiversityof
terrestrialecosystemshasreceivedlittleattention(Hawks-
worth,
1991).Amongstthoseinteractingwithlandflora,
arbuscularmycorrhizalfungi(Glomales,Zygomycotina)rep-
resentanimportantcomponentbytheirubiquityinthesoil
microbialbiomassandtheirdirectinvolvementinessential
processesattheplant-soilinterface(Harley
&:Smith,
1983;
McGee,Smith
&:Smith,
1989).Mycorrhizalassociationsare
potentialfactorsdeterminingdiversityinecosystems:they
canprobablymodifythestructureandfunctioningofaplant
community,inacomplexandunpredictableway(Grime
efal.,
Morphological
characters
Spores
Wallultrastructure
andcytochemistry
Infectionpatterns
4SBiological
characters
Ontogenyofspores
Sporegermination
Symbioticefficiency
Biogeography
Edaphicrequirements
EnvironmentaltoleranceMolecular
characters
Protein/polypeptides
profiles
Isozymepolymorphism
DNAanalysis1987;Read,
1990).Anyshift
inthemycorrhizalfungal
populationcouldhaveconsequencesforthecompositionof
plantcommunities(survivorship,competition,floristicdi-
versity),causingchangesinthebiologyofnaturalecosystems
(Miller
&Allen,
1992;Molina,Massicotte
&Trappe,
1992).
Ontheotherhand,thecompositionoftheplantcommunity
mayaffectthatofthefungalcommunity:anyfactor(e.g.
host-symbiontcombinations)causingdifferentialreproduc-
tionandsurvivalofarbuscularmycorrhizalfungi(e.g.
sporulationrates)willoperateasaselectiveforceonthe
compositionofthesoilpopulation(Giovannetti
efal.,1988;
Sanders
&Fitter,
1992).Furthermore,differentabioticfactors
(C0
2,pollutants)mayprovokemodificationsinnativeplant
communities,consequentlymodifyingthemycorrhizalstatus
oftheecosystems,andhumanactivities(chemicalinputs,crop
rotation,soilmanagement)mayhaveconsequencesforthe
dynamicsanddiversityofthefungalcommunity.Therefore,
knowledgeofthedifferentfactorsinfluencingthepopulation
biologyofarbuscularmycorrhizalfungiisessentialinany
attempttousetheminenvironmentalconservation(Allen,
1991),biotechnology(Mulongoy
efal.,1992),orinsustainable
agriculture(Bethlenfalvay
&:Linderman,
1992).
Uptonow,some
130specieshavebeendescribedinthe
Glornales,butnotallareactuallyknowntobemycorrhizal
(Walker,
1992;Walker
&:Trappe,
1993).Althoughthesefungi
shownospecificvariationsintheirrangeofhostplants,a
largevariabilitycanbefoundintheirpopulationbiology,
ecologicalspecificityandsymbioticactivity.Aputative
zygosporicstagehasbeenreportedforthelifecycleofone
fungus(GigasporadecipiensHall
&L.K.Abbott)(Tommerup
&
Sivasithamparam,
1990),butthereisnoinformationcon-
cerningtheplasmogamy,karyogamyormeiosisofthese
fungi.This,withthefactthattheyareunculturableorganisms,
MYC98