Community composition of arbuscular mycorrhizal fungi associated with native plants growing in a petroleum-polluted soil of the Amazon region of Ecuador.

Mónica Garcés‐Ruiz,Stéphane Declerck,Carolina Senés‐Guerrero,Sylvie Cranenbrouck

doi:10.1002/mbo3.703

Abstract

Arbuscular mycorrhizal fungi (AMF) are worldwide distributed plant symbionts. However, their occurrence in hydrocarbon‐polluted environments is less investigated, although specific communities may be present with possible interest for remediation strategies. Here, we investigated the AMF community composition associated with the roots of diverse plant species naturally recolonizing a weathered crude oil pond in the Amazon region of Ecuador. Next generation 454 GS‐Junior sequencing of an 800 bp LSU rRNA gene PCR amplicon was used. PCR amplicons were affiliated to a maximum‐likelihood phylogenetic tree computed from 1.5 kb AMF reference sequences. A high throughput phylogenetic annotation approach, using an evolutionary placement algorithm (EPA) allowed the characterization of sequences to the species level. Fifteen species were detected. Acaulospora species were identified as dominant colonizers, with 73% of relative read abundance, Archaeospora (19.6%) and several genera from the Glomeraceae (Rhizophagus, Glomus macrocarpum‐like, Sclerocystis, Dominikia and Kamienskia) were also detected. Although, a diverse community belonging to Glomeraceae was revealed, they represented <10% of the relative abundance in the Pond. Seventy five % of the species could not be identified, suggesting possible new species associated with roots of plants under highly hydrocarbon‐polluted conditions.

Highlights

Oil pollution is a current problem whose effects on fauna and flora are perceptible in natural as well as anthropogenic environments (Atlas & Philp, 2005; Labana, Kapur, Malik, Prakash, & Jain, 2007).It is often reported that contamination by hydrocarbons changes the microbial community structure and decreases the microbial diversity (Satyanarayana, Johri, & Prakash, 2012)
Arbuscular mycorrhizal fungi are obligate roots symbionts associated with an approximate of 72% of vascular plants (Brundrett & Tedersoo, 2018) and are occurring in almost every ecosystem (Cabello, 2001)
Their presence in hydrocarbon-polluted soils is poorly reported, though they may be of interest for remediation strategies (De la Providencia, Stefani, Labridy, St-Arnaud, & Hijri, 2015; Lenoir, Fontaine, & Lounès-Hadj Sahraoui, 2016; Lenoir, Lounes-Hadj Sahraoui, Fontaine, 2016; Rajtor & Piotrowska-Seget, 2016)

Summary

| INTRODUCTION

Oil pollution is a current problem whose effects on fauna and flora are perceptible in natural as well as anthropogenic environments (Atlas & Philp, 2005; Labana, Kapur, Malik, Prakash, & Jain, 2007). In hydrocarbon-polluted sites of the Charapa field in the Amazonian region, a natural recolonization of the abandoned weathered oil ponds was observed through the years (Garcés-Ruiz, Senés-Guerrero, Declerck, & Cranenbrouck, 2017). This suggested that plant roots and microbial communities associated with the rhizosphere were able to establish, probably enhancing the degradation of petroleum compounds, and representing a potentially important approach for the in situ treatment of hydrocarbon-polluted soils (Öztürk et al, 2015). A recent study, conducted in a hydrocarbon- polluted soil from a natural environment in the Amazonian region of Ecuador (i.e., the Charapa field, Garcés-Ruiz et al (2017)) recorded the presence of a relatively diverse community of AMF associated with various herbaceous plants. The AMF community composition in plant roots was evaluated according to the site of collection within the Pond by comparing the relative read abundance (RA) of AMF species (Loján et al, 2017; Senés-Guerrero & Schüßler, 2016a)

| MATERIALS AND METHODS

| DISCUSSION

Findings

CONFLICT OF INTEREST