Serpentine soils promote ectomycorrhizal fungal diversity

Our plain-English summary of Serpentine soils promote ectomycorrhizal fungal diversity, by S. Branco (Molecular Ecology, 2010).

The study

• Author: S. Branco
• Journal: Molecular Ecology
• Published: 2010;19(24):5566-76
• Cited by: 17 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Serpentine soils impose physiological stresses that limit plant establishment and diversity. The degree to which serpentine soils entail constraints on other organisms is, however, poorly understood. Here, I investigate the effect of serpentine soils on ectomycorrhizal (ECM) fungi by conducting a reciprocal transplant experiment, where serpentine and nonserpentine ECM fungal communities were cultured in both their native and non-native soils. Contrary to expectation, serpentine soils hosted higher fungal richness compared to nonserpentine, and most species were recovered from serpentine soil, suggesting ECM fungi are not overall specialized or strongly affected by serpentine edaphic constraints.

© 2010 Blackwell Publishing Ltd.

In plain English

This article is not about asbestos or human health. It is a soil ecology experiment on serpentine soils, and asbestos is not mentioned. The author tested whether serpentine soil, which here had much higher nickel than nonserpentine soil, limits ectomycorrhizal fungi, which live on plant roots. Oak seedlings (Quercus ilex subsp. ballota) were grown in a greenhouse in forest soil from serpentine and nonserpentine sites in the Bragança region of Portugal for 5 months in 2007. They were then moved into serpentine or nonserpentine soil, some of it sterilized, for 10 more months. DNA from root tips identified 26 fungal species. The serpentine-to-serpentine treatment had higher species richness than the nonserpentine-to-nonserpentine treatment, and pots that started in serpentine soil averaged the most species per pot. The author concluded that serpentine soils were not a strong barrier for these fungi. The author noted that the greenhouse results differed from field surveys, and that low DNA sequencing success may have left the community descriptions incomplete.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Greenhouse reciprocal transplant experiment with fungal communities from field soil, grown on oak seedlings
• Who was studied: Quercus ilex subsp. ballota oak seedlings, used as bait for ectomycorrhizal fungi. The fungi came from soils collected in serpentine and nonserpentine oak forests in the Bragança region, Portugal. Seedlings were grown from May to September 2007, then transplanted and harvested in July 2008. 985 root tips were collected, and 569 gave clean DNA sequences.
• Exposure: Serpentine soil versus nonserpentine soil, with some transplants into sterilized soil. Serpentine soil averaged 29.8 ppm nickel, compared with 1.0 ppm in nonserpentine soil. No asbestos or asbestos fiber types were studied.
• Main results:
  • 26 ectomycorrhizal fungal species were recovered across all treatments.
  • The serpentine-to-serpentine (SS) treatment had higher species richness than the nonserpentine-to-nonserpentine (NSNS) treatment. Serpentine-to-nonserpentine (SNS) had the highest richness.
  • Only two of the ten species of serpentine origin were not recovered from treatments involving nonserpentine soil.
  • Mean species per pot were: NSNS 1.28 (sd 0.84), NSS 1.37 (sd 0.56), SNS 2.08 (sd 0.82), and SS 1.83 (sd 0.69). SNS differed significantly from NSNS and from NSS.
  • Tomentella sp. 24 was absent from the SS treatment and made up 84% of root tips in the NSNS treatment, which had only four species. Laccaria sp. dominated the SS and SNS treatments.
  • Analyses of how closely related the fungi in each community were did not support serpentine soil acting as an environmental filter.
  • There were no significant differences in species per pot between transplants into sterile and nonsterile soil. The author interpreted this as native fungal communities not blocking foreign fungi.
• The authors' conclusion: The author concluded that serpentine soils are not a strong physiological barrier requiring specialization for ectomycorrhizal fungi, and that under greenhouse conditions they promoted fungal diversity.
• Limitations the authors state:
  • Greenhouse conditions virtually eliminated the arrival of fungal spores from outside, and the results differed from those observed in the field.
  • The soil used as the fungal source may not have reflected the fungal diversity present in the field.
  • Low sequencing success may have contributed to incomplete descriptions of the fungal communities.
  • The control seedlings showed a low level of fungal contamination. The author corrected the data for this.
  • The finding about sterile versus nonsterile soil applies at least to a short-term greenhouse setting.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Serpentine Group.

Related studies

• Serpentine soils do not limit mycorrhizal fungal diversity — S. Branco, R.H. Ree (2010)
• Serpentine and non-serpentine ecotypes of Collinsia sparsiflora associate with distinct arbuscular mycorrhizal fungal assemblages — S.P. Schechter, T.D. Bruns (2008)
• Fungal diversity is not determined by mineral and chemical differences in serpentine substrates — S. Daghino, C. Murat, et al. (2012)
• Serpentine soils affect heavy metal tolerance but not genetic diversity in a common Mediterranean ant — F. Frizzi, A. Masoni, et al. (2017)
• Microbial diversity and mineral composition of weathered serpentine rock of the Khalilovsky massif — I.V. Khilyas, A.V. Sorokina, et al. (2019)
• Soil fungal hyphae bind and attack asbestos fibers — E. Martino, L. Prandi, et al. (2003)

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