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Title: Role of plant relatedness in plant–soil feedback dynamics of sympatric Asclepias species
Abstract

Plants affect associated biotic and abiotic edaphic factors, with reciprocal feedbacks from soil characteristics affecting plants. These two‐way interactions between plants and soils are collectively known as plant–soil feedbacks (PSFs). The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of PSFs, although the strength and direction of feedbacks among sympatric congeners are not well‐understood. We examined plant–soil feedback responses ofAsclepias syriaca, a common clonal milkweed species, with several sympatric congeners across a gradient of increasing phylogenetic distances (A. tuberosa,A. viridis,A. sullivantii, andA. verticillata, respectively). Plant–soil feedbacks were measured through productivity and colonization by arbuscular mycorrhizal (AM) fungi.Asclepias syriacaproduced less biomass in soils conditioned by the most phylogenetically distant species (A. verticillata), relative to conspecific‐conditioned soils. Similarly, arbuscular mycorrhizal (AM) fungal colonization ofA. syriacaroots was reduced when grown in soils conditioned byA. verticillata, compared with colonization in plants grown in soil conditioned by any of the other threeAsclepiasspecies, indicating mycorrhizal associations are a potential mechanism of observed positive PSFs. This display of differences between the most phylogenetically distant, but not close or intermediate, paring(s) suggests a potential phylogenetic threshold, although other exogenous factors cannot be ruled out. Overall, these results highlight the potential role of phylogenetic distance in influencing positive PSFs through mutualists. The role of phylogenetic relatedness and evolutionary histories have recently emerged as a potential driver of plant–soil feedbacks (PSFs), although the strength and direction of feedbacks among sympatric congeners are not well‐understood. Congeneric, sympatric milkweeds typically generated positive PSFs in terms of productivity and AM fungal colonization, suggesting the low likelihood of coexistence among tested pairs, with a strength of feedback increasing as the phylogenetic distance increases.

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Award ID(s):
1946093
NSF-PAR ID:
10495358
Author(s) / Creator(s):
; ;
Publisher / Repository:
RESEARCH ARTICLE
Date Published:
Journal Name:
Ecology and Evolution
Volume:
13
Issue:
1
ISSN:
2045-7758
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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