Effect of forest fire prevention treatments on bacterial communities associated with productive Boletus edulis sites

Abstract

Summary Cistus ladanifer scrublands, traditionally considered as unproductive, have nonetheless been observed to produce large quantities of king bolete (Boletus edulis) fruitbodies. These pyrophytic scrublands are prone to wildfires, which severely affect fungi, hence the need for fire prevention in producing C. ladanifer scrublands. In addition, B. edulis productions have severely decreased in the last years. A deeper understanding of the B. edulis life cycle and of biotic and abiotic factors influencing sporocarp formation is needed to implement management practices that facilitate B. edulis production. For example, some bacteria likely are involved in sporocarp production, representing a key part in the triple symbiosis (plant–fungus–bacteria). In this study, we used soil DNA metabarcoding in C. ladanifer scrublands to (i) assess the effect of site history and fire prevention treatment on bacterial richness and community composition; (ii) test if there was any correlation between various taxonomic groups of bacteria and mycelial biomass and sporocarp production of B. edulis; and to (iii) identify indicator bacteria associated with the most productive B. edulis sites. Our results show that site history drives bacterial richness and community composition, while fire prevention treatments have a weaker, but still detectable effect, particularly in the senescent plots. Sporocarp production correlated positively with genera in Verrucomicrobia. Several genera, e.g. Azospirillum and Gemmatimonas, were identified as indicators of the most productive sites, suggesting a potential biological role in B. edulis fructification. This study provides a better understanding of the triple symbiosis (plant–fungus–bacteria) involved in C. ladanifer–B. edulis systems.

Insights into Thermophilic Plant Biomass Hydrolysis from Caldicellulosiruptor Systems Biology

“…Finally, other studies on fermenters inoculated with soil from Germany [66], and a hydrogen-generating bioreactor in the Netherlands with unknown inoculum [67] also identified different Caldicellulosiruptor species than those used in the inoculum, C. saccharolyticus. Further lines of evidence supporting the existence of "Mesocellulosiruptor" include a recent survey of soil microorganisms in Spain that identified Caldicellulosiruptor species as minor members of the soil community [68]. Of all the reports of Caldicellulosiruptor species, the most unusual may be of the identification of a C. lactoaceticus 16S rRNA gene clone from drilling fluid sampled roughly 2.5 km below the Earth's surface [69].…”

Bacterial Community Selection of Russula griseocarnosa Mycosphere Soil

“…Sorangium has rich xylan-degrading enzymes that can degrade biological macromolecules, cellulose, hemicellulose, and xylan (Tamaru et al, 2010), which is beneficial for increased mushroom productivity (Zhou et al, 2017). Singulisphaera, as an acidophilus, is also found in the rhizosphere soil of Boletus edulis (Mediavilla et al, 2019). Acidobacterium was significantly higher in plant rhizosphere soil (Oh et al, 2012;Yang et al, 2012), but their role remains to be proven in the rhizospheric process.…”

“…Soil microbes can participate in crucial processes such as biogeochemical cycles and play a role in different environmental conditions (Cao et al, 2016). Soil bacteria play an influential role in the nitrogen cycle, such as N fixation (Lladó et al, 2017), which is associated with the richness of ectomycorrhizal fungi (Allison et al, 2007;Mediavilla et al, 2019). Soil bacteria, especially mycorrhiza helper bacteria (MHB), can improve the ability of plant roots to form mycorrhiza (Aspray et al, 2006), promote the growth of fungi on soil or root surface, and trigger the germination of fungi in soil (Frey-Klett et al, 2007.…”

Leeia speluncae sp. nov., isolated from Stegodon Sea Cave in Thailand

“…Currently, there are only two species of the genus Leeia with validly published names (www.bacterio.net/leeia.html) [7]. However, members of the genus Leeia have been obtained from various environmental sources [8][9][10][11]. Some of these strains were dominant in sludge fermentation systems [12][13][14].…”