The Microbiome Structure of the Symbiosis between the Desert Truffle Terfezia boudieri and Its Host Plant Helianthemum sessiliflorum

Abstract

The desert truffle Terfezia boudieri is an ascomycete fungus that forms ect-endomycorrhiza in the roots of plants belonging to Cistaceae. The fungus forms hypogeous edible fruit bodies, appreciated as gourmet food. Truffles and host plants are colonized by various microbes, which may contribute to their development. However, the diversity and composition of the bacterial community under field conditions in the Negev desert are still unknown. The overall goal of this research was to identify the rhizosphere microbial community supporting the establishment of a symbiotic association between T. boudieri and Helianthemum sessiliflorum. The bacterial community was characterized by fruiting bodies, mycorrhized roots, and rhizosphere soil. Based on next-generation sequencing meta-analyses of the 16S rRNA gene, we discovered diverse bacterial communities of fruit bodies that differed from those found in the roots and rhizosphere. Families of Proteobacteria, Planctomycetes, and Actinobacteria were present in all four samples. Alpha diversity analysis revealed that the rhizosphere and roots contain significantly higher bacterial species numbers compared to the fruit. Additionally, ANOSIM and PCoA provided a comparative analysis of the bacterial taxa associated with fruiting bodies, roots, and rhizosphere. The core microbiome described consists of groups whose biological role triggers important traits supporting plant growth and fruit body development.

Root-secreted nucleosides: signaling chemoattractants of rhizosphere bacteria

“…Nucleosides are considered poor nutritional source for some Bacilli (Schuch et al, 1999), implying that, in the rhizosphere, they may function as signaling chemoattractant molecules rather than a carbon source. Bacilli comprises a substantial portion of the rhizosphere bacterial community (Satish et al, 2022); therefore, it was important to determine whether 2DA serves as nutrient or signaling molecule. Growing B. pumilus and E. coli in M9 medium with glucose or 2DA as the carbon source revealed that the growth rate of both bacteria was inhibited (Figure 5).…”

First Report on Truffle-Inhabiting Fungi and Metagenomic Communities of Tuber Aestivum Collected in Russia

“…Another similar species, Trichothecium roseum, has been isolated from rotten pink Chinese truffles and observed on stored desert truffles, Terfeziapinoyi Maire and Terfeziaclaveryi Chatin. This mushroom is a truffle symbiont and, presumably, can be useful for combating soil parasites (Satish et al 2022).…”