Abstract
Members of the verrucomicrobial clade ‘
Candidatus
Udaeobacter’ rank among the most dominant bacterial phylotypes in soil. Nevertheless, despite this global prevalence, in‐depth analyses with respect to pH preferences of ‘
Ca
. Udaeobacter’ representatives are still lacking. Here, we utilized a recently designed primer pair, specifically targeting ‘
Ca
. Udaeobacter’, to investigate links between soil pH and the abundance as well as phylotype composition of this largely unexplored verrucomicrobial clade. Based on 150 forest and 150 grassland soils, comprising a broad pH range, we determined the highest total abundance of ‘
Ca
. Udaeobacter’ in strongly acidic soil (pH, ~5.1) and, noteworthy, in ultra‐acidic soil (pH < 3.5) and at a pH ≥ 7, its abundance drastically declined. When we analysed the six most dominant amplicon sequence variants affiliated with ‘
Ca
. Udaeobacter’ separately, their abundances peaked within a pH range of approximately 4.7–5.2, and only in one case at slightly acidic soil pH (pH, 6.1). Our study benefits from a combination of quantitative real‐time PCR and high‐throughput amplicon sequencing, enabling for the first time a highly specific abundance analysis of representatives affiliated with ‘
Ca
. Udaeobacter’, which revealed that this globally abundant verrucomicrobial clade shows preferences for acidic soil.