Shifts in soil fungal communities in Tuber melanosporum plantations over a 20-year transition from agriculture fields to oak woodlands

Liu Bing,Carles Castaño,Christine R Fischer,Carlos Colinas,José-Antonio Bonet

doi:10.5424/fs/2016251-08353

Abstract

Aim of study: To explore the diversity of soil fungi found in black truffle (Tuber melanosporum) plantations following the introduction of the mycorrhizal-colonized host tree, (Quercus ilex), through the development of the brûlé and production of mature sporocarps.Area of study: This research was carried out province of Teruel, Aragon (central eastern Spain).Material and Methods: Soil samples from 6 plantations were collected beneath Q. ilex trees inoculated with T. melanosporum, of 3, 5, 7, 10, 14 and 20 years after out planting in truffle plantations. Soil DNA was extracted, PCR-amplified and sequenced to compare soil fungi present at different ages.Main results: As tree age increased, we observed an increased frequency of T. melanosporum (from 8% to 71% of sequenced colonies) and concomitant decrease in the combined frequency of Fusarium spp. and Phoma spp. (from 64% to 3%).Research highlights: There are important shifts in species richness and in functional groups in the soil fungal communities in maturing black truffle-oak woodland plantations. The observed inverse relationship between the frequency of soil endophytic and/or pathogenic fungi and that of the mycorrhizal mutualist T. melanosporum provides support to continue a deeper analysis of shifts in fungal communities and functional groups where there is a transition from agriculture fields to woodlands.Abbreviations used: Ectomycorrhiza (ECM) fungus; Vesicular arbuscular mycorrhiza (VAM); Operational taxonomic unit (OTU).

Highlights

The black truffle is the fruit body of the hypogeous ascomycete Tuber melanosporum Vitt., an obligate ectomycorrhizal (ECM) fungus, native to Mediterranean calcareous regions
Aim of study: To explore the diversity of soil fungi found in black truffle (Tuber melanosporum) plantations following the introduction of the mycorrhizal-colonized host tree, (Quercus ilex), through the development of the brûlé and production of mature sporocarps
This study of the community of soil fungi in black truffle plantations established on abandoned cereal fields allows us to observe an important shift over 20 years as truffle-inoculated oak trees mature and produce truffles

Summary

Introduction

The black truffle is the fruit body of the hypogeous ascomycete Tuber melanosporum Vitt., an obligate ectomycorrhizal (ECM) fungus, native to Mediterranean calcareous regions. Due to its gastronomic and economic importance, this fungus has attracted longstanding scientific attention in the interest of understanding its life cycle and for cultivation (Kües & Martin, 2011). Cultivation of black truffles can be economically profitable in marginal farmlands, promoting increased land-use stability, firebreaks and restoration of open oak woods in Mediterranean landscapes (Reyna & Garcia-Barreda, 2014). Inconsistent harvests of black truffles from plantations established with T. melanosporum-inoculated seedlings continue to challenge both scientists and farmers to look for management solutions and insight into belowground processes (Olivera et al, 2011; Zampieri et al, 2012).

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