New mutualistic fungal endophytes isolated from poplar roots display high metal tolerance.
This study aimed to isolate, identify, and characterise metal-tolerant fungi colonising poplar roots at a metal-contaminated phytoremediation site. Poplar roots were colonised by arbuscular mycorrhizal, ectomycorrhizal, and endophytic fungi, and the species were determined by ITS molecular analyses. Eight different isolates were successfully isolated into pure culture. Three isolates belonging to the Helotiales (P02, P06) and the Serendipita vermifera species (P04) were highly tolerant to metals (Cd, Zn, Pb, and Cu) compared to the mycorrhizal Hebeloma isolates. The three isolates degraded complex carbohydrates, such as xylan and cellulose, indicating that they could partially degrade root cell walls and penetrate into cells. This hypothesis was confirmed by further in vitro re-synthesis experiments, which showed that the three isolates colonised root tissues of poplar plantlets whereas two of them formed microsclerotia-like structures. Taken together, these results suggest an endophytic lifestyle of these isolates. This is the first evidence of S. vermifera as a root endophyte of poplar. A new endophytic putative species belonging to the Helotiales and closely related to Leohumicola is also reported. Interestingly, and when compared to mock-inoculated plants, both P06 and P04 isolates increased the number of root tips of inoculated poplar plantlets in vitro. Moreover, the S. vermifera P04 isolate also increased the shoot biomass. The results are discussed in relation to the potential use of endophytic strains for tree-based phytoremediation of metal-contaminated sites.
Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 CNRS/Université de Lorraine, Faculté des Sciences et Technologies, BP 70239, F-54506, Vandoeuvre-les-Nancy, France.
Laurence
L
Lacercat-Didier
Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 CNRS/Université de Lorraine, Faculté des Sciences et Technologies, BP 70239, F-54506, Vandoeuvre-les-Nancy, France.
Charlotte
C
Berthelot
Laboratoire Chrono-Environnement, UMR 6249 CNRS/Université de Bourgogne Franche-Comté, Pôle Universitaire du Pays de Montbéliard, 4 place Tharradin, BP 71427, F-25211, Montbéliard, France.
Julie
J
Foulon
Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 CNRS/Université de Lorraine, Faculté des Sciences et Technologies, BP 70239, F-54506, Vandoeuvre-les-Nancy, France.
Audrey
A
Errard
Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Turin, Italy.
Elena
E
Martino
Laboratoire Chrono-Environnement, UMR 6249 CNRS/Université de Bourgogne Franche-Comté, Pôle Universitaire du Pays de Montbéliard, 4 place Tharradin, BP 71427, F-25211, Montbéliard, France.|Faculté des Sciences et Technologies, Université de Lorraine, BP 70239, F-54506, Vandoeuvre-les-Nancy, France.
Michel
M
Chalot
Laboratoire Interdisciplinaire des Environnements Continentaux, UMR 7360 CNRS/Université de Lorraine, Faculté des Sciences et Technologies, BP 70239, F-54506, Vandoeuvre-les-Nancy, France. Damien.Blaudez@univ-lorraine.fr.
Damien
D
Blaudez
D001673:Biodegradation, Environmental; D004271:DNA, Fungal / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D008670:Metals / Q000633:toxicity*; D038821:Mycorrhizae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology*; D032107:Populus / Q000382:microbiology*; D012989:Soil Pollutants / Q000633:toxicity; D013559:Symbiosis / Q000502:physiology*
D004271:DNA, Fungal; D021901:DNA, Intergenic; D008670:Metals; D012989:Soil Pollutants
Endophytic fungi; Helotiales; Metals; Mycorrhizal fungi; Poplar; Serendipita vermifera