Combined pre-seed treatment with microbial inoculants and Mo nanoparticles changes composition of root exudates and rhizosphere microbiome structure of chickpea (<Emphasis Type="Italic">Cicer arietinum L.</Emphasis>) plants

Lichenicolous (lichen-dwelling) fungi have been extensively researched taxonomically over many years, and phylogenetically in recent years, but the biology of the relationship between the invading fungus and the lichen host has received limited attention, as has the effects on the chemistry of the host, being difficult to examine in situ. Raman spectroscopy is an established method for the characterization of chemicals in situ, and this technique is applied to a lichenicolous fungus here for the first time. Xanthoriicola physciae occurs in the apothecia of Xanthoria parietina, producing conidia at the hymenium surface. Raman spectroscopy of apothecial sections revealed that parietin and carotenoids were destroyed in infected apothecia. Those compounds protect healthy tissues of the lichen from extreme insolation and their removal may contribute to the deterioration of the apothecia. Scytonemin was also detected, but was most probably derived from associated cyanobacteria. This work shows that Raman spectroscopy has potential for investigating changes in the chemistry of a lichen by an invading lichenicolous fungus.     

Do lichen secondary compounds play a role in highly specific fungal parasitism?

Chemical interactions between highly host-specific lichenicolous fungi and their lichen hosts have been little studied. In an allometric study, we quantified carbon-based secondary compounds (CBSCs) in a mixed natural Lobarina scrobiculata population (N = 147) of the normal and the stictic acid-deficient chemotypes, both with and without galls of Plectocarpon scrobiculatae. We assessed the correlation between the presence/abundance of parasite galls and the lichen CBSCs contents, and quantified size-dependent contents of CBSCs. The parasite produced galls similarly in both chemotypes, indicating that the stictic acid complex does not deter Plectocarpon. Within both chemotypes, thalli with Plectocarpon had half the contents of all individual CBSCs than those without galls. There was a significant size-dependent increase in CBSC contents in thalli without galls, but not in those with. This study shows that lichen chemistry is involved in highly host-specific fungal parasitism, and widens our knowledge of specialized biotrophic fungal interactions.     

Lichenicolous fungi show population subdivision by host species but do not share population history with their hosts

Lichenicolous fungi are a species-rich biological group growing on lichen thalli. Here, we analyze the genetic structure of the lichenicolous basidiomycete Tremella lobariacearum and three host species (Lobaria pulmonaria, Lobaria macaronesica, and Lobaria immixta) in Macaronesia. We used ordination and analysis of molecular variance to investigate the structuring of genetic variation, and a simulation test to investigate whether rDNA haplotypes of T. lobariacearum were significantly associated with host species. To investigate the evolutionary and demographic history of the lichenicolous fungus and its hosts, we used coalescent samplers to generate trees, and Bayesian skyline plots. We found that the hosts were most important in structuring populations of the lichenicolous species. Despite their wide geographic distribution, the same haplotypes of T. lobariacearum consistently associated with a given host species. Our results suggest that the Lobaria hosts create a selective environment for the lichenicolous fungus. Both the pathogen and the host populations exhibited substantial genetic structure. However, evolutionary and demographic histories differed between the parasite and its hosts, as evidenced by different divergence times and tree topologies.     

Chemical ecology of Hobsonia christiansenii,a lichenicolous hyphomycete

Hobsonia christiansenii B. L. Brady & D. Hawksw. is a helicosporous hyphomycete reported to parasitize a number of lichen species. Quantitative study of a lichen community in Montgomery County, Maryland, revealed that H. christiansenii colonized one lichen species, Flavoparmelia baltimorensis, almost exclusively. This pattern of attack was unexpected because F. baltimorensis produces an array of phenolic secondary metabolites known to inhibit generalist herbivores and microorganisms. The chemical ecology of the pathogen was investigated further in a series of experiments designed to determine if acetone-soluble compounds from various lichens (including F. baltimorensis) inhibited growth of H. christiansenii under controlled laboratory conditions. Results demonstrated that acetone extracts of lichens other than F. baltimorensis were frequently quite inhibitory to the growth of H. christiansenii in culture, but that those of F. baltimorensis had no significant effect on the growth of the pathogen. Indeed, acetone extracts of F. baltimorensis stimulated the growth of Hobsonia on artificial media. These observations suggest H. christiansenii is a relatively specialized lichen pathogen that has been able to overcome the chemical defenses of F. baltimorensis.     

EVIDENCE FOR COMPETITIVE RELEASE IN SIMPLIFIED SAXICOLOUS LICHEN COMMUNITIES

Saxicolous cryptogam communities were sampled quantitatively on two Potomac River island habitats in June of 1980. As a result of air pollution stress, the community on one island was found to be much simpler than that found on the other island. Two relatively pollution-tolerant foliose lichen species, Xanthoparmelia conspersa and Pseudoparmelia baltimorensis, were found to dominate the communities on both islands. An examination of niche breadth and position along a light intensity gradient demonstrated that P. baltimorensis was most frequent at low light intensities and X. conspersa was most frequent at high light intensities. However, X. conspersa exhibited a niche shift toward intermediate light intensities in the species-poor community, likely the result of reduced competitor diversity in this community since the intermediate light intensities supported the greatest number of species in the species-rich community. Niche overlap between the two species was found to occur at lower light intensities in the species-poor community, suggesting that X. conspersa is more likely to appropriate intermediate light intensities in this community. The significance of competition as a regulatory factor in lichen communities has not been fully appreciated. Since lichens and other cryptogams are frequently used as indicators of environmental quality, competitive processes in naturally occurring lichen communities must be thoroughly understood before changes in species distribution that apparently result from disturbance can be properly interpreted.     

Destruction of lichen chemical defenses by a fungal

Lichen secondary metabolites are known to inhibit various animal consumers and pathogenic microorganisms. Nevertheless, many obligate fungal pathogens have evolved a tolerance to these inhibitory lichen compounds. We recently discovered a new lichen pathogen in the fungal genus Fusarium that is not only tolerant of lichen compounds but also able to degrade many of these compounds. This organism was discovered in field investigations of a different lichenicolous fungus, Marchandiomyces corallinus, which was found growing on lichens (Lasallia papulosa and L. pensylvanica) that normally inhibit its growth. Subsequent experiments established that M. corallinus is found on Lasallia species only when Fusarium is also present. We hypothesized that Fusarium altered the inhibitory chemistry of Lasallia spp. and permitted colonization by M. corallinus. A laboratory experiment to test this hypothesis demonstrated that sterilized tissues of Lasallia papulosa exposed to Fusarium for 30 d are readily degraded by M. corallinus; control tissues left in sterile water for 30 d continue to inhibit growth of M. corallinus. High performance liquid chromatography (HPLC) established that the lichen compound lecanoric acid, one of several lichen compounds that inhibit growth of M. corallinus, is degraded by extracellular enzymes produced by this newly discovered Fusarium. Taken together, our results demonstrate that enzymatic degradation of lichen compounds permits colonization of lichens by fungi that would otherwise be chemically excluded.     

Halogenated anthraquinones from the rare southern Illinois lichen Lasallia papulosa

Abstract:Four anthraquinones were isolated from the foliose lichen, Lasallia papulosa (Ach.) Llano. Two of the anthraquinones are known compounds, previously isolated from Lasallia papulosa, while the other two were reported previously as secondary metabolites from laboratory-cultured Nephroma laevigatum, and are isolated here for the first time from lichens in their natural habitat. All compounds were characterized by UV spectrophotometry, mass spectrometry, ¹H NMR and ¹³C NMR. The products were identified as 7-chloroemodin, valsarin (7-chloro-5-hydroxyemodin), 5-chloro-1- O -methylemodin and 5-chloro-1- O -methyl-ω-hydroxyemodin.     

Die parasitische FlechteLecidea insidiosa und ihre Biologie

Lecidea insidiosa, up to now regarded as a lichenicolous fungus without thallus, is a parasitic lichen, growing exclusively onLecanora varia. It kills the plectenchyma of the host, but presumably takes over part of the host-algae to build its own thallus, first inside, then outside of the host thallus. Host and parasite thallus are chemically different.Lecidea insidiosa is not related toLecidea vitellinaria, even though the two were thought to be synonymous for a long time. The species is reported for the first time from the Alps (Steiermark). It is the first known parasitic lichen to occur on a normally wood inhabiting host.

     

Lichenicolous fungi are more specialized than their lichen hosts in primeval forest ecosystems,Białowieża Forest,northeast Poland

Taxonomy and diversity of symptomatic lichenicolous fungi (visible as fruitbodies on lichen thalli, their discoloration, and/or deformation) and their specificity to lichen hosts is becoming more and more studied. However, information on their ecology is still scarce. We assess how large the specialization of these fungi towards their hosts and microhabitat is. Epiphytic, epixylic and epigeic lichens and associated lichenicolous fungi were studied on 144 permanent plots in Białowieża Forest in relation to forest communities, species of tree phorophyte and substrates. On all these three studied levels lichenicolous fungi were more specialized than their lichen hosts. Our study provides the first estimation of ecological dependences between associations of lichenicolous fungi and their hosts, microhabitats and forest communities in a primeval forest ecosystem representative of lowland Europe.     

Notes on some lichens and lichenicolous fungi from Greenland

Acarospora isortoqensis Alstrup sp. n. is described. Cornicularia mirabilis Lynge is shown to be synonymous with Endpcarpon pulvinatum Th. Fr. The spores of Muel–lerella frustulosae Vouaux are elliptical rather than spherical. Six lichens and seven lichenicolous fungi are reported as new to Greenland, and new localities are given for two lichens and one lichen parasite rarely collected in Greenland.     

<Emphasis Type="Italic">Lasiosphaeriopsis pilophori</Emphasis> sp. nov. (Sordariales) and other lichenicolous fungi on <Emphasis Type="Italic">Pilophorus</Emphasis>

Seven representatives of the Arthoniales, Dothideales, Lecanorales and Sordariales are known to occur on the lichen genus Pilophorus. Lasiosphaeriopsis pilophori sp. nov. is described from the north of the Holarctic. Cercidospora cephalodiorum is reported as new to North America. Cercidospora punctillata and Dactylospora deminuta are reported on Pilophorus for the first time. The host specificity, niche specialization and distribution of the taxa are discussed. A key to the lichenicolous fungi on Pilophorus is provided.     

The impact of polyphenolic compounds on the in vitro growth of oak-associated foliar endophytic and saprotrophic fungi

Foliar fungal endophytes are horizontally transmitted symbionts that inhabit healthy, photosynthetic tissues of all lineages of land plants where they influence plant health and productivity. Endophyte communities often are more similar among closely related hosts, potentially as a result of a preference for particular morphological, ecophysiological, or chemical host traits. However, the various ecological and evolutionary factors that drive community assembly often are difficult to disentangle. Here, we examined the impact of six polyphenolic compounds on the growth of 15 phylogenetically diverse Quercus (oak)-associated fungal species and assessed whether tolerance to phenolics is associated with their degree of specialization to oaks in nature. Despite frequently reported antifungal properties of phenolics, we found that oak-associated fungi grew the same or better than positive controls in 78% of trials with all compounds, although fungal sensitivity differed as a function of compound type and concentration. Overall, species with high specificity to Quercus had the greatest tolerance to phenolics, whereas generalists were more sensitive. Differences between generalists and specialists suggest that variation in phenolic abundance and composition among oaks may act as a selective filter that influences endophyte host associations in nature.     

Lichen-associated fungi of the Letharietum vulpinae

In the present study, a well-defined lichen community was screened for associated fungi for the first time. The photophilous lichen community Letharietum vulpinae was chosen because its character species, Letharia vulpina, was expected to host rather specialized fungi due to the presence of antimycotic secondary compounds. A considerable number of the associated fungi that were isolated were probably selective for lichens, because they appeared to be distantly related to fungi known from other substrates. The majority of these obligatory, lichen-associated fungi were only isolated in the course of the present study and represent hitherto unknown phylogenetic lineages. Parts of the lichen-associated fungi overlapped those colonizing rock surfaces or were closely related to endophytic fungi, but the lichen-associated and endophytic fungi still represented separate lineages.     

LICHEN HERBIVORE PREFERENCE: A TEST OF TWO HYPOTHESES

Field data from a saxicolous lichen community in Shenandoah National Park, Virginia, suggested that the slug Pallifera varia grazed more frequently on certain lichen species than would be expected if it fed randomly. Two hypotheses might explain this grazing pattern. The preference hypothesis, that slugs select lichens of highest quality, was tested by measuring the concentration of essential elements in lichens eliciting high and low preference by slugs. Lichens with the highest element contents were assumed to be of the highest quality to herbivores. The avoidance hypothesis, that preference by slugs actually results from the rejection of unpalatable species, was tested by offering slugs choices of baited filter-paper disks impregnated with secondary products of the lichen species in question. Results suggested that preferred lichens had significantly lower concentrations of N, P, and Ca, and that avoided lichens produced secondary products that effectively inhibited Pallifera grazing activity. These results suggested that the avoidance hypothesis was the better explanation for nonrandom Pallifera grazing patterns. Furthermore, they suggested that lichens with the highest concentrations of essential elements are most likely to produce defense compounds, an observation that supports predictions to explain patterns of chemical defense in vascular plants.     

TWO NEW SPECIES OF THE LICHEN GENUSIMMERSARIA(PORPIDIACEAE)

Immersaria olivacea, its lichenicolous fungusPolycoccum decolorans, andImmersaria mehadianaare described as new species from Spain and Romania, respectively. A new combination,Immersaria cupreoatrais proposed, and a revised concept of the generaBellemereaandImmersariais supplied.     

PROTOPARMELIA HYPOTREMELLA,A NEW STERILE CORTICOLOUS SPECIES FROM EUROPE,AND ITS LICHENICOLOUS FUNGI

Protoparmelia hypotremellavan Herk, Spier & Wirth, a sterile corticolous lichen, is described as a species new to science, so far known from Austria, SW Germany and the Netherlands. It is rapidly spreading in Germany and the Netherlands. It is apparently close toP. oleagina, and is often found growing together with that species on oak trees along roads in the Netherlands. Both species are host to the lichenicolous fungiSphinctrina anglicaandTremella wirthii.     

Epiphytic and epixylic lichen species diversity in Estonian natural forests

The epiphytic and epixylic lichen flora of natural forests was recorded in different parts of Estonia. Altogether 232 taxa of lichens, lichenicolous fungi, or non-lichenized fungi were recorded, 10 of them listed in the Estonian Red Data Book. We found regional differences in lichen species composition and diversity caused by differences in the forest types. The tree-species-rich boreo-nemoral forests had the most diverse lichen flora, while the boreal forest dominated by coniferous trees or birch had the lowest diversity. The stand age proved to be significant in regard to the number of lichen species in a forest. The most remarkable effect on the diversity of forest lichen species was caused by the presence of Populus tremula. Aspen had the highest number of lichen species on the basal trunk and twigs, and also the highest number of host-specific lichen species.     

Fungal associates of the tree-killing bark beetle,Ips typographus,vary in virulence,ability to degrade conifer phenolics and influence bark beetle tunneling behavior

The bark beetle Ips typographus carries numerous fungi that could be assisting the beetle in colonizing live Norway spruce (Picea abies) trees. Phenolic defenses in spruce phloem are degraded by the beetle's major tree-killing fungus Endoconidiophora polonica, but it is unknown if other beetle associates can also catabolize these compounds. We compared the ability of five fungi commonly associated with I. typographus to degrade phenolic compounds in Norway spruce phloem. Grosmannia penicillata and Grosmannia europhioides were able to degrade stilbenes and flavonoids faster than E. polonica and grow on minimal growth medium with spruce bark constituents as the only nutrients. Furthermore, beetles avoided medium amended with phenolics but marginally preferred medium colonized by fungi. Taken together our results show that different bark beetle-associated fungi have complementary roles in degrading host metabolites and thus might improve this insect's persistence in well defended host tissues.     

Lecanora schistina (nyl.) Arnold,a lichen with dimorphic conidia

Abstract: The lichen Lecanora schistina (Nyl.) Arnold has two kinds of conidia: filiform microconidia and obpyriform macroconidia. Both appear mixed in the same conidioma, the former being much more abundant. Sometimes these conidiomata contain a third type of conidia (microconidia) belonging most probably to a lichenicolous coelomycete living in the conidiomata of the lichen.