Urban biogeography of fungal endophytes across San Francisco

In natural and agricultural systems, the plant microbiome–the microbial organisms associated with plant tissues and rhizosphere soils–has been shown to have important effects on host physiology and ecology, yet we know little about how these plant-microbe relationships play out in urban environments...

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Main Authors: Emma Gibson, Naupaka B. Zimmerman
Format: Article
Language:English
Published: PeerJ Inc. 2023-07-01
Series:PeerJ
Subjects:
Online Access:https://peerj.com/articles/15454.pdf
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author Emma Gibson
Naupaka B. Zimmerman
author_facet Emma Gibson
Naupaka B. Zimmerman
author_sort Emma Gibson
collection DOAJ
description In natural and agricultural systems, the plant microbiome–the microbial organisms associated with plant tissues and rhizosphere soils–has been shown to have important effects on host physiology and ecology, yet we know little about how these plant-microbe relationships play out in urban environments. Here we characterize the composition of fungal communities associated with living leaves of one of the most common sidewalk trees in the city of San Francisco, California. We focus our efforts on endophytic fungi (asymptomatic microfungi that live inside healthy leaves), which have been shown in other systems to have large ecological effects on the health of their plant hosts. Specifically, we characterized the foliar fungal microbiome of Metrosideros excelsa (Myrtaceae) trees growing in a variety of urban environmental conditions. We used high-throughput culturing, PCR, and Sanger sequencing of the internal transcribed spacer nuclear ribosomal DNA (ITS nrDNA) region to quantify the composition and structure of fungal communities growing within healthy leaves of 30 M. excelsa trees from six distinct sites, which were selected to capture the range of environmental conditions found within city limits. Sequencing resulted in 854 high-quality ITS sequences. These sequences clustered into 85 Operational Taxonomic Units (97% OTUs). We found that these communities encompass relatively high alpha (within) and beta (between-site) diversity. Because the communities are all from the same host tree species, and located in relatively close geographical proximity to one another, these analyses suggest that urban environmental factors such as heat islands or differences in vegetation or traffic density (and associated air quality) may potentially be influencing the composition of these fungal communities. These biogeographic patterns provide evidence that plant microbiomes in urban environments can be as dynamic and complex as their natural counterparts. As human populations continue to transition out of rural areas and into cities, understanding the factors that shape environmental microbial communities in urban ecosystems stands to become increasingly important.
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spelling doaj.art-55d6c55edaff40b9956c7ad10fc779e72023-12-03T00:43:35ZengPeerJ Inc.PeerJ2167-83592023-07-0111e1545410.7717/peerj.15454Urban biogeography of fungal endophytes across San FranciscoEmma Gibson0Naupaka B. Zimmerman1Department of Biology, University of San Francisco, San Francisco, CA, United States of AmericaDepartment of Biology, University of San Francisco, San Francisco, CA, United States of AmericaIn natural and agricultural systems, the plant microbiome–the microbial organisms associated with plant tissues and rhizosphere soils–has been shown to have important effects on host physiology and ecology, yet we know little about how these plant-microbe relationships play out in urban environments. Here we characterize the composition of fungal communities associated with living leaves of one of the most common sidewalk trees in the city of San Francisco, California. We focus our efforts on endophytic fungi (asymptomatic microfungi that live inside healthy leaves), which have been shown in other systems to have large ecological effects on the health of their plant hosts. Specifically, we characterized the foliar fungal microbiome of Metrosideros excelsa (Myrtaceae) trees growing in a variety of urban environmental conditions. We used high-throughput culturing, PCR, and Sanger sequencing of the internal transcribed spacer nuclear ribosomal DNA (ITS nrDNA) region to quantify the composition and structure of fungal communities growing within healthy leaves of 30 M. excelsa trees from six distinct sites, which were selected to capture the range of environmental conditions found within city limits. Sequencing resulted in 854 high-quality ITS sequences. These sequences clustered into 85 Operational Taxonomic Units (97% OTUs). We found that these communities encompass relatively high alpha (within) and beta (between-site) diversity. Because the communities are all from the same host tree species, and located in relatively close geographical proximity to one another, these analyses suggest that urban environmental factors such as heat islands or differences in vegetation or traffic density (and associated air quality) may potentially be influencing the composition of these fungal communities. These biogeographic patterns provide evidence that plant microbiomes in urban environments can be as dynamic and complex as their natural counterparts. As human populations continue to transition out of rural areas and into cities, understanding the factors that shape environmental microbial communities in urban ecosystems stands to become increasingly important.https://peerj.com/articles/15454.pdfFungal endophytesBiogeographyMicrobial ecologyUrban ecologyMetrosiderosITS sequencing
spellingShingle Emma Gibson
Naupaka B. Zimmerman
Urban biogeography of fungal endophytes across San Francisco
PeerJ
Fungal endophytes
Biogeography
Microbial ecology
Urban ecology
Metrosideros
ITS sequencing
title Urban biogeography of fungal endophytes across San Francisco
title_full Urban biogeography of fungal endophytes across San Francisco
title_fullStr Urban biogeography of fungal endophytes across San Francisco
title_full_unstemmed Urban biogeography of fungal endophytes across San Francisco
title_short Urban biogeography of fungal endophytes across San Francisco
title_sort urban biogeography of fungal endophytes across san francisco
topic Fungal endophytes
Biogeography
Microbial ecology
Urban ecology
Metrosideros
ITS sequencing
url https://peerj.com/articles/15454.pdf
work_keys_str_mv AT emmagibson urbanbiogeographyoffungalendophytesacrosssanfrancisco
AT naupakabzimmerman urbanbiogeographyoffungalendophytesacrosssanfrancisco