Bacterial communities show distinctive spatial diversity patterns in productive truffle orchards amended with...

Area of Science:

• Agricultural Science
• Microbiology
• Mycology

Background:

• Truffle cultivation is expanding, with growers using practices like "truffle nests" to enhance growth.
• Truffle nests are localized peat amendments with truffle spore inoculum.
• Previous studies suggested nests have lower fungal diversity, potentially favoring pioneer truffle species.

Purpose of the Study:

• To investigate the bacterial community dynamics within truffle nests.
• To test the hypothesis that bacterial colonization precedes fungal colonization and that bacterial and fungal diversity are inversely related in truffle nests.
• To explore the relationship between bacterial communities and truffle mycelium abundance in cultivation settings.

Main Methods:

• Characterization of bacterial communities in truffle nests using 16S rRNA gene amplicon sequencing.
• Sampling conducted in two orchards over two years post-nest establishment.
• Comparison of bacterial diversity in nests versus bulk soil and commercial substrate.

Main Results:

• No drastic differences in bacterial diversity were observed between nests and bulk soil or initial substrate.
• Proteobacteria richness in nests showed a positive correlation with truffle mycelium abundance.
• A higher relative abundance of Proteobacteria was found in nests compared to bulk soil.
• Contrary to the hypothesis, fungal and bacterial richness were positively correlated within the nests.

Conclusions:

• The bacterial community composition, particularly Proteobacteria, may play a role in the success of truffle nests in plantations.
• The initial hypothesis regarding inverse fungal-bacterial diversity was not supported; richness was positively correlated.
• Further research is needed to fully elucidate the interactions between bacteria, fungi, and truffle growth in managed ecosystems.