Host-, Geographic-, and Ecological Specificity of Endophytic and Endolichenic Fungal Communities

Persistent Link:
http://hdl.handle.net/10150/202977
Title:
Host-, Geographic-, and Ecological Specificity of Endophytic and Endolichenic Fungal Communities
Author:
U'Ren, Jana M.
Issue Date:
2011
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
As one of the most diverse and ecologically important clades of life, fungi are best known as pathogens, saprotrophs, mycorrhizae, and lichens. Yet an enormous amount of previously unknown diversity occurs among endophytic and endolichenic fungi--species-rich, horizontally transmitted fungi that live within asymptomatic photosynthetic structures such as leaves and lichens. Here, I explore the biodiversity of these understudied symbiotrophs and the ecological and biogeographic factors influencing their communities.To evaluate methods currently used in ecological studies of environmental samples of fungi, I assessed inter- and intraspecific divergence of a fast-evolving locus for four genera commonly found as endophytes, and compared analytical methods for identifying and delimiting OTUs. Then I used the most robust methods to show that after soil contact, seeds of a focal tree species contain diverse fungi that are closely related to endophytes and pathogens.To explore the ecological specificity of symbiotrophic fungi, I examined endophytic, endolichenic, and saprotrophic communities inhabiting physically proximate hosts in a biotically rich area of southeastern Arizona. I found that endolichenic fungi are largely distinct from plant-associated fungi, with the exception of a group of ecologically flexible symbionts that occur in lichens and mosses. Although numerous endophytes were found in non-living leaves, fungi that were highly abundant in leaf litter were seldom found as endophytes.To assess symbiotroph biodiversity and ecological specificity at a broad geographic and phylogenetic scale, I isolated>4100 endophytic and endolichenic fungi from diverse communities of plants and lichens across five climatic regions in North America. I found that the abundance, diversity, and composition of these nearly ubiquitous fungi differ as a function of climate, locality, and host. Differences among communities reflect environmental characteristics more strongly than geographic distance.Last, I addressed a series of hypotheses regarding the ecological specificity of fungi inhabiting living and non-living leaves. I show that like endophytes, saprotrophic communities are structured by environmental characteristics, and at small spatial scales by host and leaf status. Yet, differences in communities between living leaves and leaf litter suggest that most endophytes either rapidly complete their life-cycle or are out-competed by robust saprotrophs once leaves senesce.
Type:
text; Electronic Dissertation
Keywords:
endolichenic fungi; endophytic fungi; evolution; plant-fungal symbiosis; Plant Science; Ascomycota; biogeography
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Plant Science
Degree Grantor:
University of Arizona
Advisor:
Arnold, Anne Elizabeth

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHost-, Geographic-, and Ecological Specificity of Endophytic and Endolichenic Fungal Communitiesen_US
dc.creatorU'Ren, Jana M.en_US
dc.contributor.authorU'Ren, Jana M.en_US
dc.date.issued2011-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAs one of the most diverse and ecologically important clades of life, fungi are best known as pathogens, saprotrophs, mycorrhizae, and lichens. Yet an enormous amount of previously unknown diversity occurs among endophytic and endolichenic fungi--species-rich, horizontally transmitted fungi that live within asymptomatic photosynthetic structures such as leaves and lichens. Here, I explore the biodiversity of these understudied symbiotrophs and the ecological and biogeographic factors influencing their communities.To evaluate methods currently used in ecological studies of environmental samples of fungi, I assessed inter- and intraspecific divergence of a fast-evolving locus for four genera commonly found as endophytes, and compared analytical methods for identifying and delimiting OTUs. Then I used the most robust methods to show that after soil contact, seeds of a focal tree species contain diverse fungi that are closely related to endophytes and pathogens.To explore the ecological specificity of symbiotrophic fungi, I examined endophytic, endolichenic, and saprotrophic communities inhabiting physically proximate hosts in a biotically rich area of southeastern Arizona. I found that endolichenic fungi are largely distinct from plant-associated fungi, with the exception of a group of ecologically flexible symbionts that occur in lichens and mosses. Although numerous endophytes were found in non-living leaves, fungi that were highly abundant in leaf litter were seldom found as endophytes.To assess symbiotroph biodiversity and ecological specificity at a broad geographic and phylogenetic scale, I isolated>4100 endophytic and endolichenic fungi from diverse communities of plants and lichens across five climatic regions in North America. I found that the abundance, diversity, and composition of these nearly ubiquitous fungi differ as a function of climate, locality, and host. Differences among communities reflect environmental characteristics more strongly than geographic distance.Last, I addressed a series of hypotheses regarding the ecological specificity of fungi inhabiting living and non-living leaves. I show that like endophytes, saprotrophic communities are structured by environmental characteristics, and at small spatial scales by host and leaf status. Yet, differences in communities between living leaves and leaf litter suggest that most endophytes either rapidly complete their life-cycle or are out-competed by robust saprotrophs once leaves senesce.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectendolichenic fungien_US
dc.subjectendophytic fungien_US
dc.subjectevolutionen_US
dc.subjectplant-fungal symbiosisen_US
dc.subjectPlant Scienceen_US
dc.subjectAscomycotaen_US
dc.subjectbiogeographyen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePlant Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorArnold, Anne Elizabethen_US
dc.contributor.committeememberVanEtten, Hansen_US
dc.contributor.committeememberOrbach, Marcen_US
dc.contributor.committeememberBronstein, Judith L.en_US
dc.contributor.committeememberSullivan, Matthewen_US
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