Carbon Consumption Patterns of Microbial Communities Associated with Peltigera Lichens from a Chilean Temperate Forest

Abstract

Lichens are a symbiotic association between a fungus and a green alga or a cyanobacterium, or both. They can grow in practically any terrestrial environment and play crucial roles in ecosystems, such as assisting in soil formation and degrading soil organic matter. In their thalli, they can host a wide diversity of non-photoautotrophic microorganisms, including bacteria, which play important functions and are considered key components of the lichens. In this work, using the BioLog® EcoPlate system, we studied the consumption kinetics of different carbon-sources by microbial communities associated with the thallus and the substrate of Peltigera lichens growing in a Chilean temperate rain forest dominated by Nothofagus pumilio. Based on the similarity of the consumption of 31 carbon-sources, three groups were formed. Among them, one group clustered the microbial metabolic profiles of almost all the substrates from one of the sampling sites, which exhibited the highest levels of consumption of the carbon-sources, and another group gathered the microbial metabolic profiles from the lichen thalli with the most abundant mycobiont haplotypes. These results suggest that the lichen thallus has a higher impact on the metabolism of its microbiome than on the microbial community of its substrate, with the latter being more diverse in terms of the metabolized sources and whose activity level is probably related to the availability of soil nutrients. However, although significant differences were detected in the microbial consumption of several carbon-sources when comparing the lichen thallus and the underlying substrate, d-mannitol, l-asparagine, and l-serine were intensively metabolized by both communities, suggesting that they share some microbial groups. Likewise, some communities showed high consumption of 2-hydroxybenzoic acid, d-galacturonic acid, and itaconic acid; these could serve as suitable sources of microorganisms as bioresources of novel bioactive compounds with biotechnological applications.

Nitrogen-Fixing Bacteria Associated with Peltigera Cyanolichens and Cladonia Chlorolichens

“…Through phylogenetic analyses, we were able to distinguish six haplotypes of mycobionts for Peltigera and 11 for Cladonia , all related to bipartite species. There are few studies on the lichen diversity of the Peltigera genus in the Aysén region (Chile) [17,19,23,29], but all Peltigera species identified in this work were previously reported for the Coyhaique National Reserve [17,19,23]. On the other hand, some of our Cladonia haplotypes were highly related to species of this genus, including C. stipitata (CM5) and C. chlorophaea (CM6).…”

“…According to this, PM1 was related to P. ponojensis , PM2 to P. extenuata , PM4 to P. rufescens , PM5 to the P. canina lineage ( P. evansiana , P. canina , P. “fuscopraetextata” , P. “pallidorufescens” , P. praetextata , and P. “boreorufescens” ), PM6 to P. frigida and PM8 to the P. hymenina lineage ( P. polydactylon , P. occidentalis , P. scabrosella , P. pacifica , P. hymenina, P. truculenta , and P. pulverulenta ). PM5 and PM8, according to recent phylogeny analyses and distribution patterns most-likely correspond to P. “fuscopraetextata” and P. truculenta , respectively [19,24,25].…”

“…On the other hand, little is known about how lichens acquire, structure, and transmit their associated bacterial communities. Lichens may carry part of their bacterial community with them when they reproduce vegetatively and propagate to a new site [15,16] although it cannot be ruled out that part of these bacteria could also be recruited from the substrate where lichens grow [17,18,19]. In fact, the communities of the lichen thalli are different from those of the substrates where they grow.…”

“…Although, they share certain bacteria in common [17,20]. Moreover, the lichen substrate has been proposed as one of the sources of cyanobionts [21], reinforcing the proposal that there could be a selection of members of the symbiosis from this underlying environment [17,19,20].…”

Relative genetic diversity of the rare and endangered Agave shawii ssp. shawii and associated soil microbes within a southern California ecological preserve

“…Agave‐associated soil microbes displaying little to no enzymatic activity may be indicative of more recent agave transplants. The most commonly used carbon sources (d‐galacturonic acid, n‐acetyl‐d‐glucosamine, d‐mannitol, d‐cellobiose, and γ‐amino butyric acid) are typical for soil microbiome (Almendras et al., 2018; Gomez et al., 2006; Teng et al., 2010). Base saturation, the percentage of base cations (Ca, Mg, K, etc.)…”