Interactions between Biotite and the Mineral-Weathering Bacterium Pseudomonas azotoformans F77

Abstract

In this study, the mineral-weathering bacterium Pseudomonas azotoformans F77, which was isolated from the soil of a debris flow area, was evaluated for its weathering activity under direct contact with biotite or without contact. Then, biotite-weathering behaviors of strain F77, mutants that had been created by deleting the gcd and adh genes (which are involved in gluconic acid metabolism and pilus formation, respectively), and the double mutant F77ΔgcdΔadh were compared. The relative gene expression levels of F77 and its mutants F77Δgcd and F77Δadh were also analyzed in the presence of biotite. Direct contact with biotite increased Fe and Al release from the mineral in the presence of F77. All strains had similar abilities to release Fe and Al from the mineral except for F77Δgcd and F77Δadh. Mobilized Fe and Al concentrations were decreased by up to 72, 26, and 87% in the presence of F77Δgcd, F77Δadh, and F77ΔgcdΔadh, respectively, compared to levels observed in the presence of F77 during the mineral-weathering process. Gluconic acid production was decreased for F77Δgcd and F77ΔgcdΔadh, while decreased cell attachment on the mineral surface was observed for F77Δadh, compared to findings for F77. The F77 genes involved in pilus formation and gluconic acid metabolism showed increased expression levels in the presence of biotite. The results of this study showed important roles for the genes involved in gluconic acid metabolism and pilus formation in mineral weathering by F77 and demonstrated the distinctive effect of these genes on mineral weathering by F77. IMPORTANCE Bacteria play important roles in mineral weathering and soil formation, although the molecular mechanisms underlying the interactions between bacteria and silicate minerals are poorly understood. In this study, the interactions between biotite and the highly effective mineral-weathering bacterium P. azotoformans F77 were characterized. Our results showed that the genes involved in gluconic acid metabolism and pilus formation play important roles in mineral weathering by F77. The presence of biotite could promote the expression of these genes in F77, and a distinctive effect of these genes on mineral weathering by F77 was observed in this study. Our results provide new knowledge and promote better understanding regarding the interaction between silicate minerals and mineral-weathering bacteria, as well as the molecular mechanisms involved in these processes.

Dual transcriptomics and proteomics analyses of the early stage of interaction between Caballeronia mineralivoransPML1(12) and mineral

“…All these genes (excepted pqqA) showed a significant upregulation in GB than in GBwB but supported by a low expression level. The potential regulation of the PQQ system was reported for some bacterial strains (An and Moe, 2016; Wang et al ., 2020), but other studies suggested that it may be a constitutive mechanism (Zeng et al ., 2017). Concerning the PQQ‐independent enzymes, a total of four GMC oxidoreductases were detected in this study in the genome of strain PML1(12).…”

“…Glucose is usually oxidized in the periplasm to gluconate and partially further oxidized to 2‐ketogluconate (Hanke et al ., 2013). The PQQ‐dependent GDHs are suspected to be key enzymes involved in mineral weathering (Babu‐Khan et al ., 1995; Golstein, 1995; Wang et al ., 2020). The genome of strain PML1(12) contains several enzymes related to GDH, some pyrroloquinoline quinone (PQQ)‐dependent and some other non‐PQQ dependent.…”

“…Cell attachment is known to be determined by several factors such as solution chemistry, pH and quorum sensing communications (Banfield and Nealson, 2018; Yee et al ., 2000). In addition bacteria may use molecular mechanisms requiring contact or not with mineral to allow mineral weathering (Olsson‐Francis et al ., 2010; Wang et al ., 2020). However, while the cells are able to migrate to the mineral, our microscopic observations have not evidenced the formation of a PML1(12) biofilm on the biotite particles.…”

Bacterial communities in habitats of Dongchuan, China: Their role in slate weathering in triggering and flowing areas of debris flow

“…For details, see Supplementary Methods. In addition, functions associated with siderophore biosynthesis, carbonic anhydrase (CA) [15], agellar assembly [13], and organic acid production [34] were selected as indicators of rock or mineral weathering potentials. Potential differences in the relative abundance of each rockweathering related functional category were also tested with Tukey's HSD post-hoc test.…”

Revisiting the intrageneric structure of the genusPseudomonaswith complete whole genome sequence information: Insights into Diversity and Host-related Genetic Determinants

“…Membrane-bound metaldependent hydrolase and AAA+-type ATPase are involved in the regulation of metabolism, and have been reported to contribute to metabolic adaptation to physiological host conditions and pathogenicity (Mougous et al, 2006;Parisien et al, 2008;Vermassen et al, 2019;Wyckoff et al, 2012). Furthermore, it has been reported that small RNA binding protein might contribute to virulence controlling (Djapgne et al, 2018;Law et al, 2019;Wang et al, 2020). Interestingly, it has been recently reported that P.…”