The bacterial communities of Tuber aestivum: preliminary investigations in Molise region, Southern Italy

Pamela Monaco,Gino Naclerio,Antonio Bucci,Gabriella Sferra,Marwene Toumi,Erika Tóth

doi:10.1186/s13213-020-01586-5

Pamela Monaco, Gino Naclerio + Show 4 more

Open Access

https://doi.org/10.1186/s13213-020-01586-5

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Abstract

PurposeTruffles are colonized by a complex microbial community of bacteria, yeasts, and filamentous fungi, whose role has not yet been fully understood. The main purpose of the research was to characterize the bacterial communities associated with Tuber aestivum Vittad. fruiting bodies collected from natural truffle grounds in the Molise region (Southern Italy). Despite it is one of the Italian richest areas of truffles, little is known about truffles in Molise.MethodsSix ripe fruiting bodies of Tuber aestivum Vittad. and six soil samples were collected in July 2018 at Villa San Michele in the municipality of Vastogirardi, Molise region. Then, soil and truffle microbial communities were analyzed through 16S rRNA gene sequencing on the Illumina MiSeq platform and bioinformatics analyses.ResultsConsistently with previous studies, the main phyla retrieved in the investigated ascocarps were Proteobacteria and Actinobacteria, with the genus Bradyrhizobium particularly represented. Nevertheless, significant differences between soil and truffle microbiota and an unexpected heterogeneity across truffles were observed. It is likely that a specific recruitment of bacteria from soil to ascocarps occurs during the truffle formation and that local-scale factors play an important role in determining the structure of the investigated truffle microbial communities.ConclusionAlthough further analyses (based on a larger soil and truffle sample size and aimed at defining in more detail microbial diversity, soil physical and chemical properties, microclimatic conditions, and vegetation) are required to better understand which are these factors and how they could influence the composition of truffle bacterial communities, this study represents the starting point for a deepened characterization of this economically important product.

Highlights

Most of terrestrial plant roots are colonized by mycorrhizal fungi which play a key role in soils by improving plant water and mineral nutrient uptake and receiving carbon compounds in return (Mello and Balestrini 2018)
The main purpose of this research was to characterize the bacterial communities associated with Tuber aestivum fruiting bodies collected from truffle grounds in Molise region (Southern Italy), by using generation sequencing techniques (NGS)
next generation sequencing techniques (NGS) results allowed to obtain detailed information about the composition of microbial communities in soil samples and associated with summer black truffle (Tuber aestivum) ascocarps collected from six different truffle grounds in the Molise region (Fig. 1)

Summary

Introduction

Most of terrestrial plant roots are colonized by mycorrhizal fungi which play a key role in soils by improving plant water and mineral nutrient uptake and receiving carbon compounds in return (Mello and Balestrini 2018). Bacteria can be found in inner and outer parts of truffle with densities ranging from a million to a billion cells per gram of fruiting bodies (dry weight) (Vahdatzadeh et al 2015) They seem to be selected from the soil microbial communities during the early stage of truffle formation and could play an important role in the development, growth, and nutrition of fruiting bodies (Splivallo et al 2015). Recent studies highlighted that the genus Bradyrhizobium is abundant in several Tuber species (Benucci and Bonito 2016)

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