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This work aims to demonstrate the extremophilic behavior of the lichen Pleurosticta acetabulum at extreme salinities, while maintaining its metabolic capacity to produce hydrogen. Lichen is a special micro-ecosystem that includes mostly a fungus and a green alga or cyanobacterium, as well as a microbiome. The peculiarity of this symbiotic system is its ability to dry out completely and stay inactive to survive harsh conditions. Lichens that had been dehydrated for six months revived quickly when rehydrated, restoring their photosynthetic efficiency and ability to produce hydrogen. The lichen microbiome was crucial for hydrogen production, especially through dark fermentation. The experiments of this work showed that lichen during its exposure to different salinity conditions (0 %NaCl – control, 3,5 %NaCl – sea salt concentration, 36 %NaCl – saturated salt concentration), but also after exposure to crystalline salt (100 %NaCl) could maintain the structure and the functionality of its photosynthetic apparatus. This was tested using chlorophyll a fluorescence induction measurements. Based on the results from gas chromatography with thermal conductivity detection (GC-TCD) used to determine hydrogen production, it was shown that despite being exposed to extreme salinity conditions, lichens maintained their ability to produce hydrogen. The experimental combination of lichen exposure to extreme salinities (up to 100 % NaCl), with an extreme atmosphere (100 % CO 2) and low atmospheric pressure (<10mbar), simulating Mars conditions, highlighted the functional potential of the lichen for survival in a Mars-like environment. This lichen's ability to withstand extreme conditions and to produce large amounts of hydrogen, makes it a promising candidate for future biotechnological applications, even in challenging environments like Mars, opening new astrobiological and astrobiotechnological perspectives. • Behavior of the lichen Pleurosticta acetabulum under extreme salinity conditions. • Lichens produce H 2 even under extreme salinity and Mars-like conditions. • Astrobiotechnological applications of lichen micro-ecosystems. [ABSTRACT FROM AUTHOR]

Two new species of the lichen genus Lecaimmeria are described and illustrated from Pakistan, namely, Lecaimmeria asiatica and L. crispula. The former taxon is characterized by pale brown to dark brown thallus, up to 2-mm large areoles, flat to strongly convex apothecial disc, taller hymenium 120–150 µm, apically branched, not anastomosing paraphyses, large conidia 5–7 × 1.1–1.4 µm, with respect to ecology, and the absence of secondary metabolites, whereas L. crispula can be characterized by having a light brown to chocolate brown thallus, apothecia having flat to slightly concave discs with wavy margins that curl inward, a tall hymenium150–180 μm, branched and anastomosing paraphyses, large ascospores 25–33 × 12–17 μm, and absence of secondary metabolites. A phylogenetic analysis is provided based on nrITS and nrLSU sequences that support the separation of both novel species. Comparative analyses with related species of Lecaimmeria are provided to confirm the status of these species. [ABSTRACT FROM AUTHOR]

In this study, we describe plant communities along the mesotopographic gradient in the low‐elevation subcontinental mountains of NE Finland (Utsjoki region). We sampled vascular plants, bryophytes and lichens along 18 mesotopographic ridge‐snowbed transects comprising a total of 180 plots. We used non‐metric multidimensional scaling (NMDS) ordination with envfit to explore the differentiation of plant communities in relation to mesotopography, elevation, rock cover, cover of bare ground, snowbed size and snowmelt time. The classification of communities was performed using DIANA clustering. Plant communities were differentiated along the mesotopographic gradient, snowmelt time, elevation and rock cover. The DIANA analysis distinguished seven clusters corresponding to the following communities: Betula nana–Lichenes heath, Empetrum–Myrtillus–Stereocaulon heath, Empetrum–Pleurozium–Lichenes heath, graminoid‐rich snow‐protected heath, Oreojuncus trifidus–Avenella flexuosa snow‐protected heath, Polytrichastrum sexangulare–liverwort snowbed, and Salix herbacea–Kiaeria starkei snowbed. Because of the strong impact of snowmelt time on plant community structure and distribution of communities, it is likely that climate change‐induced changes in snow conditions are affecting tundra vegetation and especially snowbeds are threatened. Snowbed communities in the Utsjoki region roughly align with previously described vegetation associations of mountain areas in NW Europe. The assignment of the graminoid‐rich snow‐protected heath community remains uncertain. [ABSTRACT FROM AUTHOR]

In the Antarctic, Arctic, and Tibetan Plateau—recognized as the Earth's three poles characterized by extremely harsh environments—lichens prevail in the ecosystem and play crucial roles as pioneer species. Despite their importance, studies investigating the spatial distribution patterns of lichen attributes are scarce due to a lack of appropriate datasets. To bridge this gap and enhance our understanding of the growth preferences of lichens in these areas, here we present a geospatial dataset encompassing key attributes of lichens, such as color type and growth form, for over 2800 lichen species and 170,000 in-situ lichen records. The dataset facilitates the creation of the first spatial distribution map illustrating the variation of lichen attributes across different latitudes and longitudes. This can serve as a foundational resource for studies on the relationship between lichen types and their growing environment, which is a vital scientific question in the ecology domain. Additionally, it can contribute to the development of specialized remote sensing technique tailored for lichen monitoring, which is currently lacking. [ABSTRACT FROM AUTHOR]

ABSTRACT The lichen genus Bagliettoa A. Massal. is being reported for the first time from India, represented by B. baldensis (A. Massal.) Vězda, B. calciseda (DC.) Gueidan & Cl. Roux, and B. limborioides A. Massal. Previously, specimens belonging to this genus were erroneously identified as species of Awasthiella and Verrucaria at herbarium LWG. Detailed descriptions, illustrations, notes on distribution and ecology, and a comparison with related species are provided along with a key to facilitate their identification. [ABSTRACT FROM AUTHOR]

In conservation strategies, getting precise and repeatable information on the species’ diet and health without relying on invasive or laborious methods is challenging. Here, we developed an efficient and non-invasive workflow for the sequencing and analysis of four taxonomic markers from fecal DNA to characterize the gut microbiota, parasites, and plants and lichens composing the winter diet of caribou (Rangifer tarandus), Canada’s most iconic endangered species. Sequencing of the 18S rRNA gene of eukaryotes from seven locations in Manitoba and Saskatchewan, Canada, allowed for the detection of five genera of parasites in caribou feces (including Nematodirella and Parelaphostrongylus) with variable frequency of occurrence depending on sampling location and sex. Our workflow also revealed a rich winter plant and lichen diet in caribou, with respectively 29 and 18 genera identified across all samples through plant and fungal ITS2 sequencing. Relationships between the gut microbiota and both the diet and parasite richness were also identified. Of note, the Central Saskatchewan sampling location was characterized by a clearly distinct gut microbiota which could be linked to an epiphytic lichen-rich diet. Overall, our results showed the potential of this multi-marker DNA metabarcoding workflow as an efficient tool to provide insights into the species biology and ecology. [ABSTRACT FROM AUTHOR]

Lichens contain a sufficient amount of plant nutrients for plant growth. Studies have shown that the characteristic secondary metabolites they produce contain significant amounts of organic acids, amino acids, and hormones. This study aims to examine the effects of 10 different lichen species Aspicilia calcarea (A. calcarea), Cetraria islandica (C. islandica), Cladonia furcate (C. furcate), Flavoparmelia caperata (F. caperata), Lobaria pulmonaria (L. pulmonaria), Pseudevernia furfuracea (P. furfuracea), Rhizoplaca chrsoleuca (R. chrsoleuca), Umbilicaria vellea (U. vellaa), Xanthoparmelia somloensis (X. somloensis), Usnea longissima (U. longissima) on metabolic properties and growth parameters of maize plant for possible use as a plant food source in sustainable and organic agriculture. As a result of the research, it was observed that when lichen species were applied as plant nutrients, there were significant increases in plant height, plant weight, dry matter ratio, some nutrient content and amino acid levels of maize compared to the control group. Among the treatments, Lobaria pulmonaria application at 5 g/kg resulted in the highest values for plant height (145.00 cm), plant weight (187.00 g), and dry matter ratio (19.21%). The research shows that different lichen species significantly affect the amino acid content, nutrient content, and growth parameters of the maize plant at various levels. [ABSTRACT FROM AUTHOR]

5α,8α-peroxyergosteryl divaricatinate (1) is isolated for the first time from acetone extract of the thallus of Cladonia cf. didyma together with condidymic (2), isodidymic (3) and barbatic (4) acids. Their UVB/UVA photoprotective and antioxidant activities were determined along with their cyto- and DNA-protecting actions against OH• damage. Compound 1 showed high UVA, cyto- (%cell viability ca. 82 at 15 µM vs 71 for OH•) and DNA (%DNA-integrity ca. 74 at 100 µM vs 22 for OH•) protecting properties. Compounds 2 and 3 exhibited high UVB (SPF ca. 40) and antioxidant activities (free radical scavenging potency EC50 = 0.6694 and 1.700 mol compound/mol DPPH•; ferric reducing power 0.392 and 0.546, at 500 ppm and inhibited lipid peroxidation); protecting cells (%cell viability ca. 76 at 15 µM) and DNA (%DNA-integrity ca. 57 at 100 µM). Compounds 1 to 3 fulfilled some physicochemical properties to act topically on the skin. [ABSTRACT FROM AUTHOR]

Lichen sclerosus is a chronic inflammatory condition of unknown etiology that affects the genital and extragenital skin, which can lead to sexual dysfunction and has been associated with vulvar cancer. The vaginal microbiome has a critical role in gynecologic health, but little is known about the microbiome in lichen sclerosus. This study investigated the vaginal and vulvar microbiomes of 27 post-menopausal women with lichen sclerosus. The most abundant genera detected in the vaginal microbiome were Lactobacillus, Gardnerella, and Anaerococcus, while Lactobacillus, Anaerococcus, and Staphylococcus were the most abundant in the vulvar microbiome. The vaginal samples clustered into two main groups, Lactobacillus dominant (n = 6, > 50% microbiome Lactobacillus) and polymicrobial (n = 21) with no dominant genus. The vulvar samples were mainly polymicrobial (n = 25). Actinomyces, Anaerococcus, and Ezakiella in the vaginal microbiome and Actinomyces and Ezakiella in the vulvar microbiome were significantly associated with lichen sclerosus symptoms (adjusted p < 0.05). In this population of post-menopausal women with lichen sclerosus the majority have diverse, non-Lactobacillus dominant microbiomes, which is considered less optimal for gynecologic health based on studies of pre-menopausal women. Actinomyces, Ezakiella, and Anaerococcus were associated with lichen sclerosus symptoms. Understanding the role of these bacteria in lichen sclerosus pathogenesis will be an essential future investigation. [ABSTRACT FROM AUTHOR]

Cliff ecosystems provide refuge to 35%–66% of the world's endemic plants. However, they face growing threats from sport climbing. Evidence suggests that unclimbed cliffs harbour approximately twice the plant richness compared with climbed cliffs, with increasing impact as climbing intensity increases. Unfortunately, it remains unknown whether the climbing impact on cliff vegetation originates from the development (opening) of climbing routes or from temporal changes resulting from subsequent climbing.We recorded cliff vascular plants and lichens at the protected natural area of El Potrero Chico (Mexico) before and after the development of new climbing routes. Subsequently, we re‐recorded the routes at sequential timepoints after 10, 20, and 30 ascents. Additionally, we examined whether the abundance of cliff vegetation influences the extent of climbing impact and whether the surroundings of the routes were also affected.We found that the opening of climbing routes exerted the strongest negative effects on cliff plants, reducing species richness by 38%, while subsequent ascents generated a minimal impact. Worryingly, route opening affected not only species richness in the route itself but also the surroundings of the routes. After 30 ascents, cliff plant abundance decreased by 60.6% within the bolted routes, whereas it decreased by 42.3% in the surroundings. However, this impact depended on the original cliff vegetation abundance. Lichen cover showed a gradual decrease, indicating that cliff‐dwelling lichens are affected not only by the opening of the route but also by subsequent ascents.Synthesis and applications: Given the almost non‐existent regulation of outdoor climbing activities in most countries, we urge the implementation of a conservation management protocol that defines clear strategies to regulate climbing activities and preserve pristine cliffs. On yet unclimbed cliffs with narrow endemic, rare, or threatened species, we propose banning the establishment of new climbing areas. On climbed cliffs lacking protected species, dynamic management actions should be implemented, such as setting a maximum number of routes that can be established and defining limits of acceptable change as climbing intensity increases. The proposed conservation management should help to halt the loss of unique cliff biodiversity and safeguard pristine cliff ecosystems. [ABSTRACT FROM AUTHOR]

• This project represents the first study of lichens at the Tswalu Kalahari Reserve. • 49 morphospecies occur across four localities. • Crustose growth forms, green algal photobionts, and sexual reproductive structures were the most commonly observed traits. • Diversity and community composition differed across distinct sites and substrates. • Environmental variables did not conclusively explain differences in diversity. The Tswalu Kalahari Reserve in the Northern Cape Province of South Africa has no previously published data on its lichen biota, which reflects the broader status of lichenology in South Africa. It is estimated that nearly half of the country's lichen species remain undescribed. Consequently, this study aimed to gather baseline data on lichen diversity and distribution across the reserve. We quantified morphological and functional diversity, characterized lichen communities, and analyzed relationships between lichen diversity and environmental variables (northness, coverage, elevation, insolation, site, substrate type, and substrate texture) using morphospecies concepts. We documented 49 morphospecies across three habitats in the Tswalu Kalahari Reserve, including at least one species that is new to science (Caloplaca tswaluensis Fryday, S. Svoboda & D. A. Ward; Fryday et al. in press) and another (Trapeliopsis glaucolepidea (Nyl.) Gotth. Schneid.) that had not previously been reported from Africa. Overall, we recorded lower diversity in corticolous (bark dwelling) lichen communities compared to saxicolous (rock dwelling) lichen communities. However, we did not find a significant effect of any measured environmental variable on saxicolous species richness. This preliminary study underscores the need for further investigation of the diverse, unrecorded lichen diversity that likely exists in other areas of the country as well as the differences in lichen communities on bark and rock substrates. This study also shows that morphospecies concepts can be informative and accessible approaches for exploratory lichen studies, particularly in regions with relatively understudied cryptogam communities. [ABSTRACT FROM AUTHOR]

Despite their ecological significance, non‐vascular photoautotrophs (NVPs) are frequently excluded from ecological experimental studies, leading to a limited comprehension of how their communities are affected by the ecosystem dynamics and an underestimation of their role in ecosystem functioning. We studied the impact of vascular plant taxonomic and functional diversity on three groups of ground NVPs (lichens, bryophytes, and cyanobacteria) within one of the longest‐running plant biodiversity experiments (Biodiversity and Ecosystem Function at Cedar Creek Ecosystem Science Reserve). Utilizing the permanent plot framework of this experiment, we analyzed the effects of almost 30 years of treatment across various levels of vascular plant taxonomic and functional diversity on NVPs. For each diversity level we documented NVP cover and richness. Using generalized linear models we evaluated the effect of vascular plant taxonomic and functional diversity, as well as environmental factors affected by vascular diversity (such as vascular plant cover, light penetration, soil nutrient content, and microtopography) on NVP richness and cover. Using these models, we conducted structural equation modeling analyses (SEM) that allowed us to differentiate the direct and indirect impacts of vascular plant taxonomic and functional diversity on NVPs. Our results showed that both lichen and bryophyte richness and cover decreased with higher vascular plant taxonomic and functional diversity, while cyanobacteria cover increased as a function of the same parameters. We also showed that microtopography serves as better predictor for lichens and bryophytes, while nutrient‐related factors perform better as predictors for cyanobacteria. Additionally, our findings indicate that NVP cover ranged from 0.001% to 100% (mean 15%) in the surveyed plots, representing a major, still ignored, component of the experimental plots. This study shows that vascular plant diversity directly and indirectly affects NVP communities, but the consequences of these effects at community and ecosystem levels are still to be explored. [ABSTRACT FROM AUTHOR]

Lichens are symbiotic organisms with unique secondary metabolism. Various metabolites from lichens have shown antimicrobial activity. Nevertheless, very few studies have investigated the antimicrobial potential of the volatile compounds they produce. This study investigates the chemical composition and antimicrobial properties of volatile compounds from Pseudevernia furfuracea collected in two regions of Morocco. Hydrodistillation was used to obtain volatile compounds from samples collected in the High Atlas and Middle Atlas. Gas chromatography–mass spectrometry (GC-MS) analysis identified phenolic cyclic compounds as the primary constituents, with atraric acid and chloroatranol being the most abundant. Additionally, eight compounds were detected in lichens for the first time. The antimicrobial activity of these compounds was assessed using disc diffusion and broth microdilution methods. Both samples demonstrated significant antimicrobial effects against multidrug-resistant human bacteria, reference microorganisms, fish pathogens, and Candida albicans, with minimum inhibitory concentrations (MICs) ranging from 1000 µg/mL to 31.25 µg/mL. This study provides the first report on the volatile compounds from Pseudevernia furfuracea and their antimicrobial effects, particularly against fish pathogens, suggesting their potential as novel antimicrobial agents for human and veterinary use. Further research is warranted to explore these findings in more detail. [ABSTRACT FROM AUTHOR]

Tropical dry forests (TDFs) are unique ecosystems with high biodiversity, including a rich variety of lichen species. Lichens are sensitive to environmental changes and can serve as bioindicators of ecosystem health. This study examined the diversity of lichen communities at four TDF sites in the Atlántico Department of Colombia. More than 700 tree lichen specimens were collected and identified at the four sites. A total of 135 species of lichens were identified, of which 19 are possibly undescribed. The most diverse sites were Usiacurí and Repelón, both protected areas with relatively well-preserved forests. The findings of this study demonstrate that the Atlántico TDFs host a large diversity of lichens, with a significant number of records of new species. The observed differences in species composition between sites highlight the importance of habitat heterogeneity and anthropogenic pressures on lichen communities. The results emphasize the need for conservation strategies to protect these ecologically valuable lichen communities within the Atlántico TDFs. [ABSTRACT FROM AUTHOR]

Restoration efforts to maintain oak-dominated habitats and enhance biodiversity often employ selective thinning, but its long-term effect on multiple taxa remains unclear. This study examines the effects of halo thinning around pedunculate oak on epiphytic and tree-related microhabitat (TreM) diversity in the boreal–nemoral forest zone. We revisited nine sites in Latvia with 150–331-year-old oaks, where thinning was conducted in 2003–2004. Epiphyte species composition and cover were assessed, and TreMs were evaluated using standardised methods. Diversity indices (Hill numbers, q = 0; 1; 2; 3) and statistical models (LMMs, Poisson GLMMs) were used to analyse the effects of thinning on species richness and TreM occurrence. Halo thinning over the past 20 years has not caused significant differences in epiphyte or TreM diversity, though managed trees exhibited a higher occurrence of the most common microhabitats. These findings suggest halo thinning may enhance specific TreM features but do not substantially promote epiphyte and TreM diversity. Future research should implement systematic monitoring, deriving the relationships between the conditions after the thinning and their effects, thus serving as the basis for adaptive habitat management strategies. Expanding the scope of such studies is essential for developing evidence-based forest management strategies. [ABSTRACT FROM AUTHOR]

Phytochemical composition and antimicrobial, antibiofilm, and antioxidant effects of a newly described Himalayan lichen Placidium deosaiense Usman and Khalid growing in Pakistan were investigated. HPLC–DAD methods were used for identification of secondary metabolites in acetone and methanol extracts. The total phenolics content was measured using a spectrophotometric method. The study investigated the antioxidant (DPPH-scavenging activity assay and reducing-power assay), antibacterial (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)), and antibiofilm (inhibition of biofilm formation and reduction in mature biofilm) activities of extracts of the lichen P. deosaiense and isolated parietin. The chemical constituents olivetol, olivetolic acid, haematommic acid, fallacinol, and parietin were identified as major compounds in the tested extracts of the lichen. Parietin was isolated from the acetone extract on a separation column. The methanol extract had higher values of TPC (21.67 mg GAE/g) than the acetone extract. Isolated parietin showed the best antioxidant activity measures, according to the DPPH-scavenging activity assay (IC50 = 51.616 μg/mL) and reducing-power assay. Although the extracts showed the best antibacterial activity (especially against Proteus mirabilis ATCC 12453), parietin demonstrated superior antibiofilm activity (especially against Staphylococcus aureus ATCC 25923). This is the first report on the phytochemical composition of the lichen Placidium deosaiense and the first description of the chemical composition of some of the 45 species of the genus Placidium. This research will pave the way for further exploration of new activities of this lichen and its metabolites, which are important for medicine and pharmacy. [ABSTRACT FROM AUTHOR]

Being poikilohydric, lichens are inherently exposed to alternating desiccation and hydration cycles. They can exhibit extraordinary resistance to extreme temperatures in a dehydrated state but thermal thresholds for hydrated lichens are lower. The ability of the lichen Cetraria aculeata to recovery after high temperature treatment (40°C, 60°C) at different air humidity levels (relative humidity [RH]: <15%, 25%, 50%, 75%, ≅100%) was examined to find a linkage between passive dehydration of the lichen and its physiological resistance to heat stress. The response to heating was determined by measuring parameters related to photosynthesis and respiration after 2‐ and 24‐h recovery. A higher RH level resulted in a slower decline in relative water content (RWC) in hydrated thalli. In turn, the stress resistance of active thalli depended on the ambient humidity and associated RWC reduction. Elevated temperature had a negative impact on bioenergetic processes, but only an unnatural state of permanent full hydration during heat stress resulted in a lethal effect. Hydrated lichen thalli heated at 40°C and 50% relative humidity (RH) tended to be least susceptible to stress‐induced damage. Although atypical climatic conditions may lead lichens to lethal thresholds, the actual likelihood of deadly threat to lichens due to heat events per se is debatable. Summary statement: Passive dehydration of lichens is a property that protects them well against the lethal effects of extreme temperatures. Heat stress takes its toll on viability of Cetraria aculeata but only in the unnatural state of its full hydration leads to fatal inhibition of photosynthesis and respiration. [ABSTRACT FROM AUTHOR]

The fragmentation and degradation of primary forests are serious threats to the long-term persistence not only of the tree species they comprise, but also of many organisms inhabiting them. The Canarian laurel forest, known as monteverde, is a highly threatened endemic forest of the Macaronesian region. Lichens are considered ideal bioindicators for assessing the effects of human disturbances on ecosystems and anticipating the response of other less sensitive organisms. However, no studies have used them as model organisms to analyze the conservation status of this primary forest in the Macaronesian region. In the present study, we analyzed several variables of the lichen biota of the Canarian laurel forest on the islands with the highest representation within this archipelago: La Gomera, La Palma, and Tenerife. We analyzed the species richness (and its relationship to island size with the real and potential vegetation areas of the laurel forest); the lichen diversity value, the number of shared and exclusive species on each of the islands as well as lichen functional traits as they have become important for evaluating the response of epiphytic lichens to environmental changes. The results indicate that there are signs of a potential extinction debt occurring in the diversity of epiphytic lichens in some areas. Furthermore, it has been observed that, despite the presence of some exclusive species on each island, the overall composition does not differ between them. Considering the functional traits of lichens, there are patterns that can provide information about the unique characteristics of the laurel forest of each of the studied islands. [ABSTRACT FROM AUTHOR]

In the present work, the phytotoxic effects of secondary metabolites extracted from lichen Ramalina celastri (usnic acid) and lichen Stereocaulon ramulosum (a naturally occurring mixture of atranorin and perlatolic acid, approx. 3:1) on cultures of the aposymbiotically grown lichen photobiont Asterochloris erici were evaluated. Algae were cultivated on the surface of glass microfiber disks with applied crystals of lichen extracts for 14 days. The toxicity of each extract was tested at the two selected doses in quantities of 0.01 mg/disk and 0.1 mg/disk. Cytotoxicity of lichen extracts was assessed using selected physiological parameters, such as growth (biomass production) of photobiont cultures, content of soluble proteins, chlorophyll a fluorescence, chlorophyll a integrity, contents of chlorophylls and total carotenoids, hydrogen peroxide, superoxide anion, TBARS, ascorbic acid (AsA), reduced (GSH) and oxidized (GSSG) glutathione, and composition of selected organic acids of the Krebs cycle. The application of both tested metabolic extracts decreased the growth of photobiont cells in a dose-dependent manner; however, a mixture of atranorin and perlatolic acid was more effective when compared to usnic acid at the same dose tested. A higher degree of cytotoxicity of extracts from lichen S. ramulosum when compared to identical doses of extracts from lichen R. celastri was also confirmed by a more pronounced decrease in chlorophyll a fluorescence and chlorophyll a integrity, decreased content of chlorophylls and total carotenoids, increased production of hydrogen peroxide and superoxide anion, peroxidation of membrane lipids (assessed as TBARS), and a strong decrease in non-enzymatic antioxidants such as AsA, GSH, and GSSG. The cytotoxicity of lichen compounds was confirmed by a strong alteration in the composition of selected organic acids included in the Krebs cycle. The increased ratio between pyruvic acid and citric acid was a very sensitive parameter of phytotoxicity of lichen secondary metabolites to the algal partner of symbiosis. Secondary metabolites of lichens are potent allelochemicals and play significant roles in maintaining the balance between mycobionts and photobionts, forming lichen thallus. [ABSTRACT FROM AUTHOR]

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Cancer, a complex group of diseases marked by uncontrolled cell growth and invasive behavior, is characterized by distinct hallmarks acquired during tumor development. These hallmarks, first proposed by Douglas Hanahan and Robert Weinberg in 2000, provide a framework for understanding cancer's complexity. Targeting them is a key strategy in cancer therapy. It includes inhibiting abnormal signaling, reactivating growth suppressors, preventing invasion and metastasis, inhibiting angiogenesis, limiting replicative immortality, modulating the immune system, inducing apoptosis, addressing genome instability and regulating cellular energetics. Usnic acid (UA) is a natural compound found in lichens that has been explored as a cytotoxic agent against cancer cells of different origins. Although the exact mechanisms remain incompletely understood, UA presents a promising compound for therapeutic intervention. Understanding its impact on cancer hallmarks provides valuable insights into the potential of UA in developing targeted and multifaceted cancer therapies. This article explores UA activity in the context of disrupting hallmarks in cancer cells of different origins based on recent articles that emphasize the molecular mechanisms of this activity. [ABSTRACT FROM AUTHOR]

Lichens are increasingly recognised as valuable bioindicators for environmental heavy metal pollution due to their sensitivity to spatial and temporal variations in pollution levels and their ability to adapt to diverse and often harsh habitats. This review initially examines the mechanisms of metal absorption in lichens, including particulate entrapment, ion exchange, and intracellular absorption, as well as their physiological responses to abiotic stressors such as heavy metal exposure and desiccation. In the latter part, we compile and synthesise evidence showing that secondary metabolites in lichens are significantly influenced by metal concentrations, with varying impacts across different species. Although extensive research has addressed the broader physiological effects of heavy metal hyperaccumulation in lichens, there remains a significant gap in understanding the direct or indirect influences of heavy metals on the lichen microbiome, possibly mediated by changes in secondary metabolite production. Our review integrates these aspects to propose new research directions aimed at elucidating the mechanisms underlying physiological responses such as resilience and adaptability in lichens. Overall, this review highlights the dynamic interplay between microbiome composition, secondary metabolite variation, and metal accumulation, suggesting that these factors collectively contribute to the physiological responses of lichens in polluted environments. [ABSTRACT FROM AUTHOR]

Abstract In conservation strategies, getting precise and repeatable information on the species’ diet and health without relying on invasive or laborious methods is challenging. Here, we developed an efficient and non-invasive workflow for the sequencing and analysis of four taxonomic markers from fecal DNA to characterize the gut microbiota, parasites, and plants and lichens composing the winter diet of caribou (Rangifer tarandus), Canada’s most iconic endangered species. Sequencing of the 18S rRNA gene of eukaryotes from seven locations in Manitoba and Saskatchewan, Canada, allowed for the detection of five genera of parasites in caribou feces (including Nematodirella and Parelaphostrongylus) with variable frequency of occurrence depending on sampling location and sex. Our workflow also revealed a rich winter plant and lichen diet in caribou, with respectively 29 and 18 genera identified across all samples through plant and fungal ITS2 sequencing. Relationships between the gut microbiota and both the diet and parasite richness were also identified. Of note, the Central Saskatchewan sampling location was characterized by a clearly distinct gut microbiota which could be linked to an epiphytic lichen-rich diet. Overall, our results showed the potential of this multi-marker DNA metabarcoding workflow as an efficient tool to provide insights into the species biology and ecology.

Acarospora socialis, the bright cobblestone lichen, is commonly found in southwestern North America. This charismatic yellow lichen is a species of key ecological significance as it is often a pioneer species in new environments. Despite their ecological importance virtually no research has been conducted on the genomics of A. socialis. To address this, we used long-read sequencing to generate the first high-quality draft genome of A. socialis. Lichen thallus tissue was collected from Pinkham Canyon in Joshua Tree National Park, California and deposited in the UC Riverside herbarium under accession #295874. The de novo assembly of the mycobiont partner of the lichen was generated from Pacific Biosciences HiFi long reads and Dovetail Omni-C chromatin capture data. After removing algal and bacterial contigs, the fungal genome was approximately 31.2 Mb consisting of 38 scaffolds with contig and scaffold N50 of 2.4 Mb. The BUSCO completeness score of the assembled genome was 97.5% using the Ascomycota gene set. Information on the genome of A. socialis is important for California conservation purposes given that this lichen is threatened in some places locally by wildfires due to climate change. This reference genome will be used for understanding the genetic diversity, population genomics, and comparative genomics of A. socialis species. Genomic resources for this species will support population and landscape genomics investigations, exploring the use of A. socialis as a bioindicator species for climate change, and in studies of adaptation by comparing populations that occur across aridity gradients in California.

The paper presents an annotated list of lichens of the eastern slope of Berutarube volcano, one of the most inaccessible and poorly studied active volcanoes on Iturup Island. Samples of lichens were collected in August 2023 from eroded areas in the summit part of the volcano, as well as on the eastern slope along the Andrey Creek, in the upper reaches of which unnamed cold acidic springs discharge. In total, 53 species of lichens were identified from the sampling sites, of which 20 species were new to Iturup Island, 2 species were new to the Kuril Islands, and 1 species was new to the Sakhalin region. In the summit part of the volcano, lichens typical for areas of volcanic activity were identified: Cladonia crispata, Cladonia straminea, Huea confluens, Lecidea plana, Melanelia stygia, Pseudephebe pubescens, Rhizocarpon badioatrum, and Umbilicaria torrefacta. The influence of the solfataric gases of the volcano on the lichen biota of the Andrey Creek valley has not been revealed, which allows us to make the assumption that there is no direct influence of the products of the solfataric activity of Berutarube volcano on the natural environment of its eastern slopes.

Abstract Biocrusts represent associations of lichens, green algae, cyanobacteria, fungi and other microorganisms, colonizing soils in varying proportions of principally arid biomes. The so-called grit crust represents a recently discovered type of biocrust situated in the Coastal Range of the Atacama Desert (Chile) made of microorganisms growing on and in granitoid pebbles, resulting in a checkerboard pattern visible to the naked eye on the landscape scale. This specific microbiome fulfills a broad range of ecosystem services, all probably driven by fog and dew-induced photosynthetic activity of mainly micro-lichens. To understand its biodiversity and impact, we applied a polyphasic approach on the phototrophic microbiome of this biocrust, combining isolation and characterization of the lichen photobionts, multi-gene phylogeny of the photobionts and mycobionts based on a direct sequencing and microphotography approach, metabarcoding and determination of chlorophylla+b contents. Metabarcoding showed that yet undescribed lichens within the Caliciaceae dominated the biocrust together with Trebouxia as the most abundant eukaryote in all plots. Together with high mean chlorophylla+b contents exceeding 410 mg m−2, this distinguished the symbiotic algae Trebouxia as the main driver of the grit crust ecosystem. The trebouxioid photobionts could be assigned to the I (T. impressa/gelatinosa) and A (T. arboricola) clades and represented several lineages containing five potential species candidates, which were identified based on the unique phylogenetic position, morphological features, and developmental cycles of the corresponding isolates. These results designate the grit crust as the only known coherent soil layer with significant landscape covering impact of at least 440 km2, predominantly ruled by a single symbiotic algal genus.

Two isidiate species, Sticta arenosella and S. cellulosa , are reported from South America for the first time and the former species also as new to Southern Hemisphere. Sticta arenosella was found in Chile and S. celulosa in Bolivia. The identification of both species was confirmed by sequencing of the nuITS rDNA marker, a universal barcode of fungi, and the haplotype network analyses. Specimen of S. celulosa possess sparse apothecia, which previously have not been observed in this species.

Structural modifications in lichen phenolic compounds have been one of the tools to potentiate their biological activity. In the present work, seven alkyl derivatives of norstictic acid were prepared and evaluated against eight cell lines. Norstictic acid was isolated from the lichen Ramalina anceps and the alkyl derivatives were obtained through reactions with alcohols. Cytotoxicity was evaluated against the 786-0 (kidney carcinoma), MCF7 (breast carcinoma), HT-29 (colon carcinoma), PC-03 (prostate carcinoma), HEP2 (laryngeal carcinoma), B16-F10 (murine melanoma), UACC-62 (human melanoma), and NIH/3T3 (mouse embryonic fibroblast) cell lines using the sulforhodamine B assay. Norstictic acid exhibited poor activity, while the 8'-O-n-butyl-norstictic acid and 8'-O-sec-butylnorstictic acid derivatives showed potential activity (GI50 values of 6.37-45.0 µM and 6.8-52.40 µM, respectively) and high selectivity (selectivity index (SI) values of 13.88-98.11 and SI 11.30-87.40, respectively) against all tumor cells. The 8'-O-n-hexyl-norstictic acid showed good activity (5.96-9.53 µM) and moderate selectivity (SI 9.2-5.76) against MCF7, HT-29, PC-03, and HEP2 cells, while 8'-O-isopropyl-norstictic acid demonstrated high activity and selectivity against PC-03 cells (GI50 1.28 µM and SI 33.8), and was highly active but moderately selective against UACC, HEP2, and B16-F10 cells (GI50 6.2, 7.78, and 9.65 µM; SI 7.0, 5.5, and 4.5, respectively). Additionally, 8'-O-n-pentyl- and 8'-O-tert-butyl-norstictic acids were active and selective against PC-03 cells (GI50 8.77 and 7.60 µM; SI 6.53 and 5.0, respectively). Chemometric analysis revealed a clear relationship between all compounds and their biological activities. The insertion of a four-carbon alkyl chain (n-butyl and sec-butyl) produced potentially active compounds on all tested tumor cells. [ABSTRACT FROM AUTHOR]

In this study, we aimed to elucidate some of the mechanisms of cell death induced by lobaric acid in A549 (human lung cancer) cells. For this purpose, the effects of cytotoxic concentrations on p53 and caspase-3 gene expressions were investigated. A549 cells were treated with varying concentrations of lobaric acid (12.5, 25, 50, and 100 μg/ml) for 48 hours and then their viability was evaluated and p53 and caspase-3 mRNA expressions were determined at statistically cytotoxic concentrations of 12.5, 50, and 100 μg/ml. According to beta-actin, it was determined that the increase in lobaric acid concentration revealed an upward trend in p53 and caspase-3 mRNA expressions. Furthermore, quantum chemical parameters such as frontier molecular orbitals, band gap energy and ionization potential, electronic affinity, chemical softness, chemical potential, electrophilicity index and chemical hardness were analyzed. Furthermore, molecular docking was performed to identify the binding sites and the binding behavior of lobaric acid to some target proteins (P53, Caspase-3 and Bcl-2). [ABSTRACT FROM AUTHOR]

During the Mars 160 Mission in 2016 and 2017, crews at the Mars Desert Research Station (MDRS) in Utah, USA and the Flashline Mars Arctic Research Station (FMARS) on Tallurutit (Devon Island), Nunavut, Canada, conducted a collections‑based survey of lichen biodiversity at each of these Martian planetary analogs. Here we present the results of these studies as two annotated checklists, including 35 lichen spe‑ cies from MDRS and 13 species from FMARS, alongside details on the distribution of these species, relevant taxonomic notes, and photos of each species as an identification aid. This work adds to our knowledge of the biodiversity of these unique sites and provides an important baseline for future analog research at these stations. [ABSTRACT FROM AUTHOR]

The fruticose lichen Stereocaulon vesuvianum is among the most abundant and widespread lichens in upland Britain. It typically produces cephalodia (nodules) that contain the cyanobacterium Stigonema, which can fix atmospheric nitrogen. However, over much of England, Wales, and southern Scotland S. vesuvianum no longer produces cephalodia and does not fix nitrogen, a morphological change linked to elevated atmospheric nitrogen deposition. This provided a unique opportunity to compare the 15N natural abundance signatures in N2‐fixing and non‐N2‐fixing lichen populations, keeping in mind that fixed nitrogen has a 15N content close to that of atmospheric N2 while, in comparison, several components of atmospheric combined N (e.g. nitrate and ammonium in precipitation) tend to be 15N depleted. We found that in N2‐fixing samples, there was a steep gradient in 15N relative abundance in the terminal 15 mm of thallus branches (pseudopodetia), changing from 15N depleted tissues at 10–15 mm below the tips to values close to that of atmospheric N2 at the apices while in non‐N2‐fixing samples thallus branches were uniformly 15N depleted. The 15N gradient in N2‐fixing material could not be explained by the presence of cephalodia since these are more abundant towards branch bases. The data provide the first evidence in lichens of translocation of recently fixed N to sink regions of active growth and production of asexual reproductive propagules, bringing lichens into line with N source‐sink relationships in N2‐fixing plant symbioses. [ABSTRACT FROM AUTHOR]

Soil salinization is a major environmental threat to the entire terrestrial ecosystem. Lichens arose from the symbiosis of fungi and algae or cyanobacteria. They have a high tolerance to various extreme environments, including adaptation to saline‐alkali habitats. Thus, lichens are pioneer species on saline‐alkali soil. However, the separate resilience of the two symbiotic partners under saline‐alkali conditions remains insufficiently understood. In this study, two representative symbiotic algae, Diplosphaera chodatii and Trebouxia jamesii, were studied for their physiological response to the saline‐alkali stress by adjusting different concentrations of NaHCO3, together with their respective symbiotic fungi Endocarpon pusillum (terricolous lichen) and Umbilicaria muhlenbergii (saxicolous lichen). The results indicate that cell growth rate and biomass in all four cultures decreased in alkali‐alkaline substrate, while cellular activities and ultrastructure were affected to a distinct extent. Compared with the symbiotic fungi, the algae were found to be more active in coordinating oxidative stress and lipid peroxidation damage under the saline‐alkali stress. The antioxidant system of the alga was especially shown as a key adaptive trait and it provides an important strategy for species survival and persistence in arid saline‐alkali desert. The specific survival ability of the lichen symbiosis relies on the stress resilience advantages of the symbiotic partners in combination. Our study provided new insights into understanding the adaptation of lichen symbiosis to desert saline‐alkali soil, and the potential of lichen symbiotic algae in the future desert ecological restoration. [ABSTRACT FROM AUTHOR]

Spotting thin-layer chromatography (TLC) plates can be sped up dramatically by using micropipette tips for simultaneous extraction and delivery of lichen substances. High quality results can be obtained in half the time or less for the most time-consuming step in TLC of lichens, spotting the plates. [ABSTRACT FROM AUTHOR]

Lichens are symbiotic associations between fungi (the mycobiont) and algae or cyanobacteria (the photobionts). They synthesize a large number of secondary metabolites, many of which are potential sources of novel molecules with pharmacological and industrial applications. The advancement of in vitro culture methods of lichen-forming fungi would allow the comprehensive application of these compounds at large scales, enable improvements in the synthesis, facilitate understanding of the role of the partners in the synthesis of these compounds and increase our knowledge about the genes associated with secondary metabolites production. The aim of this work is to summarize the nutritional and physicochemical requirements that have been used to date to culture different lichen-forming fungi species. In total, the requirements for the cultivation of 110 species are presented. This review can provide a starting point for future experiments and help advance the methods of culturing lichenized fungi. The type of diaspore selected to isolate the mycobiont, the composition of the isolation and culture media and the corresponding physicochemical parameters are essential in designing an efficient lichen culture system, allowing the achievement of a suitable growth of lichen-forming fungi and the subsequent production of secondary metabolites. [ABSTRACT FROM AUTHOR]

The genus Xanthoparmelia includes several subcrustose, squamulose, small foliose, and small subfruticose species, primarily in the Southern Hemisphere. Here, we report on the first small foliose species lacking usnic acid in the genus occurring in the Holarctic. The species has been previously known as Lecanora olivascens Nyl., but subsequent studies of the morphology, secondary chemistry, and molecular data of the nuITS rDNA indicate that this species instead belongs to Xanthoparmelia. Consequently, the new combination Xanthoparmelia olivascens (Nyl.) V.J. Rico and G. Amo is proposed, and an epitype is designated here. We discuss the unique presence of a subcrustose Xanthoparmelia species lacking cortical usnic acid in the Northern Hemisphere. This species fits phylogenetically into a clade that was previously only known from the Southern Hemisphere, and hence represents another example of N-S disjunction in lichenized fungi. [ABSTRACT FROM AUTHOR]

There are a number of rather anecdotal reports of plant growth on power cables in the Americas, but until now there has been no systematic attempt to gauge the geographical extension of this phenomenon nor a documentation of the diversity of species found there. Using observations from the participatory science data platform iNaturalist and the scientific literature, we document almost 700 occurrences of more than 40 species of vascular plants and three lichen species on power cables with a geographical distribution over 7000 km from the southern United States to northern Argentina. Based on these observations we discuss the ecological conditions of plant growth on power cables in terms of climate; elevational distribution; and the morphological, physiological, and life history traits that allow the observed set of species to thrive on this anthropic structure. [ABSTRACT FROM AUTHOR]

Tangshan is known as a typical heavy industrial city with serious atmospheric pollution. It suffers the most serious atmospheric pollution during the winter heating period. This study aims to explore the level and spatial distribution of atmospheric element deposition in the study area and validate the suitability of Ramalina sinensis (RSI) as an active biomonitor in North China cities. RSI was transplanted to Tangshan in winter (Dec. 2016- Mar. 2017) and exposed for 17 weeks. The concentration of 51 elements was tested using an ICP-MS (inductively coupled plasma mass spectrometer). The results showed that the exposure concentration of all elements but Ag was significantly higher than the background value. Principal component analysis (PCA) showed that K, P, and Rb were separated into the group G5, and these nutrients have a lower level of bioaccumulation than other groups. The remaining 47 elements were classified into groups G1 (Al, Be, Co, Cr, Cs, Ge, Li, Nb, Ni, Si, Th, Ti, U, V, and 16 rare earth elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc) of crustal origin, G2 (Ca, Cd, Cu, Mg, Mn, Mo, S, Sb, Sr, and Zn) and G3 (Bi, Pb, and Sn) of atmospheric origin, and G4 (As, Fe, Se, and Tl) of crustal-atmospheric origin. The overall bioaccumulation in Tangshan is moderate (PLIzone = 2.010 for the combined groups G1-4), with the highest bioaccumulation level (high to severe) for the atmospheric group G2. The most concerned elements are Ca and S, which are of high bioaccumulation at the regional scale. All element groups show a similar spatial pattern characterized by decreasing atmospheric deposition from east to west and from rural to urban areas. These results indicate that RSI is a good active biomonitor for most elements, barring some nutrients. The importance of G2 elements should be emphasized as an indicator of anthropogenic emissions in lichen-active biomonitoring techniques in North China cities. The study area experienced a certain degree of atmospheric pollution, contributed mainly by the frequent industrial and agricultural activities and coal combustion for heating in the east of the city and the rural areas around. This study is the first to monitor atmospheric deposition in industrial cities in North China using the active lichen biomonitoring method. [ABSTRACT FROM AUTHOR]

Peltula shalae Kumar S. is described as a new species of lichens from the Chenab Valley of Jammu and Kashmir, India. It is characterised by peltate-umbilicate thallus comprising of overlapping squamules forming rosettes, with diameter 2–3.5 cm. The absence of soredia is notable. This lichen is observed to grow on 'shale rock', a type of sedimentary rock, and is distinguished from closely related species, including P. daurica, P. sonorensis, P. anthracina , and P. obscurans by its distinct morphological features. Furthermore, a comprehensive comparison with closely related peltate-umbilicate species is presented. [ABSTRACT FROM AUTHOR]

The dry forests of southern Ecuador are characterized by a great floristic variety and high endemism rates in different taxonomic groups; however, these forests are disappearing at an alarming rate due to anthropogenic disturbances. Epiphytic cryptogams (bryophytes and lichens) are important in seasonally dry tropical forests (SDTFs) and, due to their physiology (poikilohydric species), are sensitive to the changes associated with specific human disturbances. We examined the response of epiphytic cryptogams to habitat disturbance in SDTFs (natural and semi-natural forests) by registering the frequency and coverage of epiphytic cryptogams on 182 trees. We recorded a total of 53 epiphytic cryptogams (47 lichens and 6 bryophytes). A greater number of species was found in the natural forest, with 51 species, than the semi-natural forests (DFs), which had 45 species. We found that total richness tended to decrease with increased intensity of disturbance. The impoverishment was particularly related to the reduction in tree density and diversity (e.g., selective logging) in semi-natural compared to natural forests. However, the epiphytic composition showed little relationship with forests disturbance. We conclude that anthropic disturbance, particularly selective logging, are the main factors affecting the diversity of epiphytic cryptogams in the SDTFs from southern Ecuador. [ABSTRACT FROM AUTHOR]

The analysis of the interaction between main bionts (mycobiont and photobiont) in the lichen symbiosis delivers substantial information about their preferences in the selection of symbiotic partners, and their ecological preferences. The selectivity in the Parmelia genus has been defined as strong so far. However, data on this lichen genus, which includes several widely distributed species, are biogeographically limited. Therefore, using specialization indicators and extended sampling, in this study, we estimated the interactions between the main bionts of selected Parmelia spp., using two levels of estimation (species/OTU and haplotype). A comparison of mycobiont-photobiont interactions at different levels showed that considering only mycobiont species and Trebouxia OTUs, greater specialization is found, while Parmelia species studied in this work present a more generalistic strategy in photobiont choice when haplotypes are considered. Despite the uneven sampling of Parmelia species, the interpretation of specialization within species and individuals of the genus leads to a more precise and accurate interpretation of their adaptation strategies. Furthermore, the data from P. sulcata indicate the existence of a different pool of compatible haplotypes in some geographical regions compared to neighboring areas. This observation suggests the potential influence of climatic factors. [ABSTRACT FROM AUTHOR]

A significant part of our stone heritage is made of limestone. Researchers are increasingly concerned about the risk of biodeterioration of these important objects. In this article, we present an up-to-date review of the microbial diversity of biodeteriorated limestone cultural heritage (CHL). This is based on an extensive bibliographic search of the literature investigating biodiversity using culture-dependent (CD) and culture-independent (CI) techniques. In the case of the former, only articles in which microorganisms were identified using molecular tools that generate DNA sequences were selected, with the aim of providing traceable identification based on the sequences submitted to public databases. The literature search resulted in the selection of 50 articles published between 2004 and 2023. The biodiversity data obtained from the CHL were organized into the following groups: fungi (626 records), bacteria and cyanobacteria (786 and 103 records, respectively), algae (51 records), and archaea (27 records). Within each group, the microbial diversity studied was compared according to results obtained using CD and CI techniques. Of all the articles selected, 12 used both approaches, demonstrating the growing effort to discover the total microbiome of biodeteriorated cultural heritage assets. [ABSTRACT FROM AUTHOR]

A new spiroterpenoid, namely tinctorin (1), along with one known compound, norreticulatin (2), were isolated from the lichen Parmotrema tinctorum (Despr. ex Nyl.) Hale. Their structures were elucidated by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. The absolute configuration of 2 was established for the first time. Compound 1 was evaluated for its inhibitory activity against α-glucosidase and found to be inactive. [ABSTRACT FROM AUTHOR]

Biocrusts represent associations of lichens, green algae, cyanobacteria, fungi and other microorganisms, colonizing soils in varying proportions of principally arid biomes. The so-called grit crust represents a recently discovered type of biocrust situated in the Coastal Range of the Atacama Desert (Chile) made of microorganisms growing on and in granitoid pebbles, resulting in a checkerboard pattern visible to the naked eye on the landscape scale. This specific microbiome fulfills a broad range of ecosystem services, all probably driven by fog and dew-induced photosynthetic activity of mainly micro-lichens. To understand its biodiversity and impact, we applied a polyphasic approach on the phototrophic microbiome of this biocrust, combining isolation and characterization of the lichen photobionts, multi-gene phylogeny of the photobionts and mycobionts based on a direct sequencing and microphotography approach, metabarcoding and determination of chlorophylla+b contents. Metabarcoding showed that yet undescribed lichens within the Caliciaceae dominated the biocrust together with Trebouxia as the most abundant eukaryote in all plots. Together with high mean chlorophylla+b contents exceeding 410 mg m−2, this distinguished the symbiotic algae Trebouxia as the main driver of the grit crust ecosystem. The trebouxioid photobionts could be assigned to the I (T. impressa/gelatinosa) and A (T. arboricola) clades and represented several lineages containing five potential species candidates, which were identified based on the unique phylogenetic position, morphological features, and developmental cycles of the corresponding isolates. These results designate the grit crust as the only known coherent soil layer with significant landscape covering impact of at least 440 km2, predominantly ruled by a single symbiotic algal genus. [ABSTRACT FROM AUTHOR]

Background: Lichens are micro-ecosystems relying on diverse microorganisms for nutrient cycling, environmental adaptation, and structural support. We investigated the spatial-scale dependency of factors shaping the ecological processes that govern lichen-associated bacteria. We hypothesize that lichens function as island-like habitats hosting divergent microbiomes and promoting landscape gamma-diversity. Three microenvironments —thalli, substrates, and neighboring soils— were sampled from four geographically overlapping species of Peltigera cyanolichens, spanning three bioclimatic zones in the Chilean Patagonia, to determine how bacterial diversity, assembly processes, ecological drivers, interaction patterns, and niche breadth vary among Peltigera microenvironments on a broad geographical scale. Results: The hosts' phylogeny, especially that of the cyanobiont, alongside climate as a secondary factor, impose a strong ecological filtering of bacterial communities within Peltigera thalli. This results in deterministically assembled, low diverse, and phylogenetically convergent yet structurally divergent bacterial communities. Host evolutionary and geographic distances accentuate the divergence in bacterial community composition of Peltigera thalli. Compared to soil and substrate, Peltigera thalli harbor specialized and locally adapted bacterial taxa, conforming sparse and weak ecological networks. Conclusions: The findings suggest that Petigera thalli create fragmented habitats that foster landscape bacterial gamma-diversity. This underscores the importance of preserving lichens for maintaining a potential reservoir of specialized bacteria. [ABSTRACT FROM AUTHOR]

Simple Summary: This paper reports on three new species and a new record of the lichen genus Peltula Nyl., highlighting research progress on lichen diversity in Helan Mountain. In this study, species were identified through a combination of morpho-anatomy, molecular systematics, and chemical substance detection. The results of the study enrich the data of Peltula and the study of lichens in Helan Mountain. In this study, a systematic taxonomic analysis was carried out on the lichen genus Peltula, collected from Helan Mountain in China; three new species (Peltula helanense, P. overlappine, and P. reticulata) and a new record (P. crispatula (Nyl.) Egea) for China were identified. Four species were identified by morph-anatomical, chemical, and phylogenetic analyses by combining two gene loci (ITS and LSU). Peltula helanense is with tiny individual thalli up to 1mm, attached by creamy-white cylindrical rhizoids and apothecia filling the whole squamule. Peltula overlappine is characterized by thallus squamulose forming rosette-shaped patches and squamules with distinctive thickened margins. Peltula reticulata is characterized by brownish brown thallus and squamules with densely reticulate upper surface. P. crispatula is characterized by irregular squamules attached to a tuft of hyphae. The four species are described in detail, compared, and discussed with similar species, and images of morpho-anatomical structures of the four species are also provided. Moreover, a key to the species of Peltula from Helan Mountain is provided. The results enrich the data of the genus Peltula and also indicate that the rich diversity of lichen species in Helan Mountain is worthy of in-depth study. [ABSTRACT FROM AUTHOR]

The effect of dust pollution on the photosynthesis and respiration parameters of foliose lichens Hypogimnia physodes (L.) Nyl, Lobaria pulmonaria (L.) Hoffm. and Peltigera aphthosa (L.) Willd., collected near the bauxite mine (Komi Republic, Russia) was investigated. Microscopic analysis showed that fine dust particles were mainly on the thalli surface, with a few mineral inclusions in the thalli medulla. The deposition of dust particles caused significant changes in the optical properties of the lichen surface in the visible and infrared spectral regions. A number of spectral indices (BRI, REP, RES, WI) sensitive to lichen pollution by dust emissions from the bauxite mine were identified due changes in the reflectance spectra of the thalli. Shading of the algal layer by mineral particles deposited on the thalli surface did not affect the content of photosynthetic pigments and PS II photochemical activity parameters. At the same time, lichen CO2-exchange parameters were observed to change. Lichen thalli from the polluted area were characterized by lower values of net CO2 uptake in the moderate light conditions (150 µmol PAR/m2 s), and the proportion of dark respiration in the gas exchange was 1.5 to 2 times higher than the values for thalli from background site. A 2-fold decrease in cytochrome respiration capacity was observed in thalli from the affected area. In thalli of L. pulmonaria and P. aphthosa, the energetically inefficient alternative respiratory pathway capacity increased 1.5‑fold and in H. physodes the activity of residual respiration increased more than 3.5-fold. The results obtained allowed an assessment of the chronic dust pollution effects on the foliose lichens symbionts functioning. The data may be useful for environmental biomonitoring. [ABSTRACT FROM AUTHOR]

The paper presents the first-ever report of lichens from Sholayar 10 ha permanent plot, with a total of 38 species under 23 genera and 14 families. Of these, one species, Allographa cinerea (Fée) Lücking and Kalb reported as new to India, and nine species namely Coenogonium dilucidum (Kremp.) Kalb and Lücking, Crypthonia albida (Fée) Frisch, Enterographa divergens (Müll. Arg.) Redinger, Graphis indica J. Kalb and Kalb, Malmidea fuscella (Müll. Arg.) Kalb and Lücking, Malmidea piae (Kalb) Kalb, Malmidea subgranifera (Kalb and Elix) Kalb and Elix, and Porina subinterstes (Nyl.) Müll. Arg. as new distributional records to Kerala. The genus Crypthonia is reported for the first time in Kerala. [ABSTRACT FROM AUTHOR]

Three species of the genus Psora are recognized in India including Psora crenata (Taylor) Reinke, P. decipiens (Hedw.) Hoffm. and P. himalayana (C. Bab.) Timdal. Among them, P. crenata is described as a new record to the lichen biota of India. Descriptions, illustrations and distributions are provided for each species together with a key to all species of Psora known from India. [ABSTRACT FROM AUTHOR]

Sterols play important structural and regulatory roles in numerous intracellular processes. Unlike animals, plants contain a distinctive and diverse variety of sterols. Recently, information has emerged showing that stigmasterol is a "stress sterol". Stigmasterol is synthesized via the mevalonate biosynthesis pathway and has structural similarity to β-sitosterol but differs in the presence of a trans-oriented double bond in the side chain. In plants, the accumulation of stigmasterol has been observed in response to various stresses. However, the precise ways that stigmasterol is involved in the stress responses of plants remain unclear. This comprehensive review provides an update on the biology of stigmasterol, particularly the physicochemical properties of this ethylsterol, its biosynthesis, and its occurrence in higher plants and extremophilic organisms, e.g., mosses and lichens. Special emphasis is given to the evolutionary aspects of stigmasterol biosynthesis, particularly the variations in the gene structure of C22-sterol desaturase, which catalyzes the formation of stigmasterol from β-sitosterol, in a diversity of evolutionarily distant organisms. The roles of stigmasterol in the tolerance of plants to hostile environments and the prospects for its biomedical applications are also discussed. Taken together, the available data suggest that stigmasterol plays important roles in plant metabolism, although in some aspects, it remains an enigmatic compound. [ABSTRACT FROM AUTHOR]

Biological soil crusts (biocrusts) can thrive under environmental conditions that are stressful for vascular plants such as high temperatures and/or extremely low moisture availability. In these settings, and in the absence of disturbance, cover of biocrusts commonly exceeds cover of vascular plants. Arid landscapes are also typically slow to recover from disturbance and prone to altered vegetation and invasion by exotic species. In the sagebrush ecosystems, cover of annual, exotic, invasive grasses are lower where cover of biocrusts and vascular plants are greater, suggesting that biocrusts play a role in helping arid sites avoid conversion to dominance by invasive grasses. The conceptual framework for assessing ecological resistance and resilience (R&R) is used across the region to estimate the risk of invasion by annual grasses and the likelihood of recovery of native plants following disturbance. However, this framework does not currently account for biocrusts. We used data collected by the Bureau of Land Management Assessment, Inventory, and Monitoring program to relate biocrusts, specifically the presence of lichens and mosses, to the R&R framework. Lichens frequently occur on warm, dry sites, classified as lower R&R. Mosses frequently occur on sites classified as moderate or moderately low R&R. Without management practices that favor biocrusts in low‐moderate R&R, these areas may be more vulnerable to transitioning from being dominated by shrubs to annual grasses. Under climate change scenarios, the area occupied by lower R&R sites is likely to increase, suggesting that the role of biocrusts in maintaining site resistance to invasion may also increase. [ABSTRACT FROM AUTHOR]