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Abstract Nearly all plants are colonized by fungal endophytes, and a growing body of work shows that both environment and host species shape plant-associated fungal communities. However, few studies place their work in a phylogenetic context to understand endophyte community assembly through an evolutionary lens. Here, we investigated environmental and host effects on root endophyte assemblages in coastal Louisiana marshes. We isolated and sequenced culturable fungal endophytes from roots of three to four dominant plant species from each of three sites of varying salinity. We assessed taxonomic diversity and composition as well as phylogenetic diversity (mean phylogenetic distance, MPD) and phylogenetic composition (based on MPD). When we analyzed plant hosts present across the entire gradient, we found that the effect of the environment on phylogenetic diversity (as measured by MPD) was host dependent and suggested phylogenetic clustering in some circumstances. We found that both environment and host plant affected taxonomic composition of fungal endophytes, but only host plant affected phylogenetic composition, suggesting different host plants selected for fungal taxa drawn from distinct phylogenetic clades, whereas environmental assemblages were drawn from similar clades. Our study demonstrates that including phylogenetic, as well as taxonomic, community metrics can provide a deeper understanding of community assembly in endophytes.
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Phylogenetic Distance Metrics for Studies of Focal Species in Communities: Quantiles and Cumulative Curves
The phylogenetic distance between species often predicts differences in ecologically important traits. The phylogenetic diversity and structure of biological communities can inform our understanding of the processes that shape those communities, and there is a well-developed framework for comparing phylogenetic structures of communities. However, particularly in studies of phylogenetic distances from one focal species to other members of its assemblage (a one-to-many framework), the standard metrics of community-wide studies encounter significant limitations due to the left-skewed distribution of pairwise phylogenetic distances in most biological communities. For studies that require estimating the degree of phylogenetic isolation of a focal taxon, the mean phylogenetic distance (MPD) usually provides little power to distinguish among taxa because it is heavily weighted by the many ways to be distantly related, whereas the nearest taxon distance (NTD) is highly idiosyncratic and ignores cases where multiple close relatives may contribute equally strongly to influence the focal species. Here we highlight the value of examining the cumulative distribution of phylogenetic distances in studies that take a focal-species approach. We describe and discuss the benefits of two new metrics. An integrated metric of phylogenetic distances (AUPhyDC) uses information from the whole cumulative distribution, whereas the tenth quantile (PD10) is an extremely simple metric that improves on NTD by capturing the influence of multiple close relatives on ecological interactions. Several recent examples found that PD10 did a better job of revealing ecological patterns than NTD or MPD. We provide R code to facilitate the use of these approaches and advocate for the inclusion of PD10 along with NTD and MPD in statistical packages for phylogenetic ecology.
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- Award ID(s):
- 1655896
- PAR ID:
- 10385028
- Date Published:
- Journal Name:
- Diversity
- Volume:
- 14
- Issue:
- 7
- ISSN:
- 1424-2818
- Page Range / eLocation ID:
- 521
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Nearly all plants are colonized by fungal endophytes, and a growing body of work shows that both environment and host species shape plant-associated fungal communities. However, few studies place their work in a phylogenetic context to understand endophyte community assembly through an evolutionary lens. Here we collected data to investigate environmental and host effects on root endophyte assemblages in coastal Louisiana marshes. We isolated and sequenced culturable fungal endophytes from roots of three-four dominant plant species from each of three sites of varying salinity. We provide data on abundance and taxonomy of the isolated fungal taxa as well as phylogenetic diversity (mean phylogenetic distance, MPD) and phylogenetic composition (based on MPD).more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/d14070521
