Metabarcoding analysis of the rhizosphere microbiome of Saxifraga berica (Bég.) D.A. Webb, an endemic chasmophyte of the Colli Berici

Saxifraga berica (Bég.) D.A. Webb is an endemic plant of Colli Berici, Vicenza province, N-E Italy. It grows in small crags and crevices of the mudstone rocks, including coves, caves, temporary streams and cliffs, showing a certain degree of variability in light tolerance. According to the IUCN Council, it is considered a vulnerable species and is protected according to Habitat Directive (92/43/CEE). The aim of this study is to characterise the soil rhizosphere microbiome of S. berica, understanding peculiar microbiome association connected with this conservation-valuable species and this habitat. Sampling was carried out between late May and early June, with at least two ecological niches selected: one in a light-exposed area and one in an unexposed area. Metabarcoding analyses were then conducted on 52 samples, selecting 16S primers (V3 and V4) for bacteria and ITS for fungi. The results of the analyses show significant diversity in the bacterial and fungal compositions of the soil based on habitat type, light exposure, collection core and the presence or absence of the plant. The output of this research will enhance the understanding of the species ecological niche, facilitating more targeted conservation management strategies.