Publications des agents du Cirad

Cirad

How deep can ectomycorrhizas go? A case study on Pisolithus down to 4 meters in a Brazilian eucalypt plantation

Robin A., Pradier C., Sanguin H., Mahe F., Lambais G.R., de Araujo Pereira A.P., Germon A., Cintra Santana M., Tisseyre P., Pablo A.L., Heuillard P., Sauvadet M., Bouillet J.P., Dini Andreote F., Plassard C., De Moraes Gonçalves J.L., Bran Nogueira Cardoso E.J., Laclau J.P., Hinsinger P., Jourdan C.. 2019. Mycorrhiza, 29 (6) : p. 637-648.

Despite the strong ecological importance of ectomycorrhizal (ECM) fungi, their vertical distribution remains poorly understood. To our knowledge, ECM structures associated with trees have never been reported in depths below 2 meters. In this study, fine roots and ECM root tips were sampled down to 4-m depth during the digging of two independent pits differing by their water availability. A meta-barcoding approach based on Illumina sequencing of internal transcribed spacers (ITS1 and ITS2) was carried out on DNA extracted from root samples (fine roots and ECM root tips separately). ECM fungi dominated the root-associated fungal community, with more than 90% of sequences assigned to the genus Pisolithus. The morphological and barcoding results demonstrated, for the first time, the presence of ECM symbiosis down to 4-m. The molecular diversity of Pisolithus spp. was strongly dependent on depth, with soil pH and soil water content as primary drivers of the Pisolithus spp. structure. Altogether, our results highlight the importance to consider the ECM symbiosis in deep soil layers to improve our understanding of fine roots functioning in tropical soils.

Mots-clés : profondeur; enracinement; pisolithus; ectomycorhize; eucalyptus grandis; plantation forestière; brésil

Thématique : Production forestière; Biologie du sol; Physiologie végétale : croissance et développement

Documents associés

Article de revue

Agents Cirad, auteurs de cette publication :